Hydrophobins are small amphiphilic proteins that are conserved in filamentous fungi. They localized on the conidial surface to make it hydrophobic, which contributes to conidial dispersal in air, and help fungi to infect plants and mammals and to degrade polymers. Hydrophobins self-assemble and undergo structural transition from the amorphous state to the rodlet (rod-like multimeric structure) state. However, it remains unclear whether the amorphous or rodlet state is biologically functional and what external factors regulate state transition. In this study, we analyzed the self-assembly of hydrophobin RolA of Aspergillus oryzae in detail and identified factors regulating this process. Using atomic force microscopy, we observed RolA rodlet formation over time, and determined "rodlet elongation rate" and "rodlet formation frequency." Changes in these kinetic parameters in response to pH and salt concentration suggest that RolA rodlet formation is regulated by the strength of ionic interactions between RolA molecules.

We report experimental findings of spontaneous perpendicular orientation and successive kinking of microdomains in film specimens of block copolymer by solution cast using selective solvent. These phenomena were firstly found out by our experiments. It is notable that only conducting solution cast is a straightforward and sophisticated to obtain perpendicular orientation of cylindrical and lamellar microdomains because mainly reported methods utilize application of external fields such as electric, magnetic, or temperature gradient field. The key point of this method exists in utilization of selective solvent which possesses different degrees of solubility for two respective components of block copolymer. The specimen used is a polystyrene-block-poly(ethylene-butylene)-block-polystyrene triblock copolymer and selective solvents were n-heptane, dichloromethane, and toluene, which are selectively good solvents for PEB (poly(ethylene-butylene)), PS (polystyrene), and PS, respectively. Furthermore, mixtures of n-heptane and dichloromethane were used for more precise control of the degree of selectivity. To analyze the nano structures in the as-cast and annealed specimens, transmission electron microscopy and two-dimensional small-angle X-ray scattering (2d-SAXS) measurements were conducted at room temperature. As a result, the edge-view 2d-SAXS pattern relevant to the kinking was obtained for the as-cast specimens by using toluene for the solution cast. To explain the mechanism, schematic illustrations are presented with the idea of spontaneous parallel orientation of cylinders or lamellae, and successive kinking during further solvent evaporation.

Advancements in nanotechnology and materials science have led to an increased demand for specific material functions, preparation, and design of polymer particles with ordered internal and surface mesostructures. In this work, well-shaped spheres of poly(2,2,2-trifluoroethyl methacrylate)-b-poly(2-vinylpyridine) with four different molecular weights are prepared by 3D confined self-assembly. After thermal annealing, these spheres exhibit ordered internal and surface mesostructure. Analytical studies suggest that the internal mesoporous structure is formed by the microphase separation properties of the diblock copolymers, while the formation of ordered mesopores on the surface is caused by the decomposition of the PTFEMA domains under electron irradiation. Other microphase-separated structures, such as cylindrical and lamellar ones, are observed using solution casting and non-solution casting methods in the same diblock copolymer, indicating that the 3D confined environment induces the formation of internal ordered spherical microphase-separated structures in the particles.

Pore-selective silver (Ag)-functionalized honeycomb-patterned (HCP) polystyrene (PS) films were fabricated via a modified breath figure method using an interfacial chemical reaction and its application for an antibacterial film using the role of micro-trapping pit was systematically studied. PS polymer solution containing ferrocene which acts as a reducing agent was cast under humid conditions containing silver nitrate (AgNO3) to induce an interfacial chemical reaction between ferrocene and AgNO3 at the water droplet/polymer solution interface. The confinement of Ag+ to the humidity is possible due to the formation of the water complex of Ag+ such as Ag+(H2O)n stabilized by the Lennard–Jones potential and electrostatic interactions. Ag+ may be carried to the polymer solution surface via the water humidity despite being a heavy metal. Scanning electron microscopy and elemental mapping analysis revealed that the pores of the obtained films were selectively coated by Ag. The contact angle of the HCP porous films was greatly decreased by the pore selective Ag functionalization, which acts as a micro-trapping pit for the antibacterial activity. The antibacterial activity of the film against Escherichia coli and Staphylococcus aureus was assessed by the micro-dilution method, selective fluorescence imaging, and crystal violet assay. The study of BF for a functional HCP film by accompanying an interfacial chemical reaction for the pore-selective Ag functionalization shows that specific metal or inorganic materials could be pore-selectively functionalized by a similar method under several conditions, thus potentially giving the HCP films various applications.

Hydrophobins are small secreted amphipathic proteins ubiquitous among filamentous fungi. Hydrophobin RolA produced by Aspergillus oryzae attaches to solid surfaces, recruits polyesterase CutL1, and thus promotes hydrolysis of polyesters. Because the N-terminal region of RolA is involved in the interaction with CutL1, the orientation of RolA on the solid surface is important. However, the kinetic properties of RolA adsorption to solid surfaces with various chemical properties remain unclear, and RolA structures assembled after the attachment to surfaces are unknown. Using a quartz crystal microbalance (QCM), we analyzed the kinetic properties of RolA adsorption to the surfaces of QCM electrodes that had been chemically modified to become hydrophobic or charged. We also observed the assembled RolA structures on the surfaces by atomic force microscopy and performed molecular dynamics (MD) simulations of RolA adsorption to self-assembled monolayer (SAM)-modified surfaces. The RolA-surface interaction was considerably affected by the zeta potential of RolA, which was affected by pH. The interactions of RolA with the surface seemed to be involved in the self-assembly of RolA. Three types of self-assembled structures of RolA were observed: spherical, rod-like, and mesh-like. The kinetics of RolA adsorption and the structures formed depended on the amount of RolA adsorbed, chemical properties of the electrode surface, and the pH of the buffer. Adsorption of RolA to solid surfaces seemed to depend mainly on its hydrophobic interaction with the surfaces; this was supported by MD simulations, which suggested that hydrophobic Cys-Cys loops of RolA attached to all SAM-modified surfaces at all pH values. IMPORTANCE The adsorption kinetics of hydrophobins to solid surfaces and self-assembled structures formed by hydrophobin molecules have been studied mostly independently. In this report, we combined the kinetic analysis of hydrophobin RolA adsorption onto solid surfaces and observation of RolA self-assembly on these surfaces. Since RolA, whose isoelectric point is close to pH 4.0, showed higher affinity to the solid surfaces at pH 4.0 than at pH 7.0 or 10.0, the affinity of RolA to these surfaces depends mainly on hydrophobic interactions. Our combined analyses suggest that not only the adsorbed amount of RolA but also the chemical properties of the solid surfaces and the zeta potential of RolA affect the self-assembled RolA structures formed on these surfaces.

Understanding the transmission of nanoscale forces in the pico-to-nanonewton range is important in polymer physics. While physical approaches have limitations in analyzing the local force distribution in condensed environments, chemical analysis using force probes is promising. However, there are stringent requirements for probing the local forces generated before structural damage. The magnitude of those forces corresponds to the range below covalent bond scission (from 200 pN to several nN) and above thermal fluctuation (several pN). Here, we report a conformationally flexible dual-fluorescence force probe with a theoretically estimated threshold of approximately 100 pN. This probe enables ratiometric analysis of the distribution of local forces in a stretched polymer chain network. Without changing the intrinsic properties of the polymer, the force distribution was reversibly monitored in real time. Chemical control of the probe location demonstrated that the local stress concentration is twice as biased at crosslinkers than at main chains, particularly in a strain-hardening region. Due to the high sensitivity, the percentage of the stressed force probes was estimated to be more than 1000 times higher than the activation rate of a conventional mechanophore.

The separation of oil and water is an important technology for solving a wide range of water-related problems such as purification of industrial wastewater. Herein, the fabrication of an extremely thin oil–water separation membrane is reported by precisely controlling the wettability of a honeycomb (HC) porous membrane. The developed membrane can easily separate water and oil by gravity and capillary force. The method of wettability control by UV–O3 treatment and the resultant change in the separated liquid are discussed. Amphiphilic perforated HC films with controlled wettability can be used in membranes that can separate different liquids according to their densities when the initial liquid added to the surface of the HC film is changed.

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are important processes for various energy devices, including polymer electrolyte fuel cells, rechargeable metal–air batteries, and water electrolyzers. We herein report the preparation of a rare metal-free and highly efficient ORR/OER electrocatalyst by calcination of a mixture of blood meal and ascidian-derived cellulose nanofibers. The obtained carbon alloys showed high ORR/OER performances and proved to be promising electrocatalysts. The carbon alloys synthesized entirely from biomass resources not only lead to a new electrocatalyst fabrication process but also contribute to CO2 reduction and the realization of a good life-cycle assessment value in fabrication of a sustainable energy device.

The oxygen reduction reaction (ORR) at the cathode is one of the critical bottlenecks in the energy conversion process in polymer electrolyte fuel cells (PEFCs) and metal-air batteries. An iron azaphthalocyanine unimolecular layer (Fe-AZUL) adsorbed onto a carbon substrate exhibited high ORR activity as an alternative of Pt supported on carbon black (Pt/C) electrocatalyst. We herein report the synthesis of various AzPc molecules with different peripheral structures and complex metals, as well as measurements of the ORR activities of catalysts containing the synthesized molecules and carbons. The catalytic activities were characterized by electrochemical analysis, density functional theory (DFT) calculations, and measurements of ionization potential (IP) values. From the results, the IP values on Ketjen Black (KB) were found to be one of the significant indicators for high ORR activities, providing a guideline for the development of high-performance electrocatalysts.

A hierarchical flower-like ordered arrangement of the pores in the porous film was explored by combination of the breath figure technique and layer-by-layer solution casting process. A layer-by-layer polymers system of polystyrene (PS) and polyimide (PI) was used to form uniform surface for the casting instead of the non-uniform surface of blended polymers. From top and cross-sectional SEM images, surface flower-like pores, and bottom spherical pores interconnected each other are imaged. The pore shape was tunable from spherical to obovate by controlling the interfacial tension between the condensed water and the polymer solution. Based on the deep experimental observation, the formation mechanism for flower-like ordered hierarchical porous structure was proposed.

We propose a surface modification of poorly dispersive polytetrafluoroethylene (PTFE) particles via bioinspired polydopamine-polyethyleneimine (PDA-PEI) which conferred PTFE particles a uniform dispersion in aqueous medium. With increasing dopamine concentration in the reaction solution, dispersity of PTFE particles improved and the surface charges of particles changed from negative to positive due to an increase of surface coverage of PDA-PEI layers. Simplicity of the method here outlines an attractive route for surface modification of inert surfaces useful for large-scale applications.

In nature, laccase enzymatically catalyzes the reaction of phenolic compounds with oxygen to produce hardened surfaces known as cuticles on insects and plants. Inspired by this natural process, the present work investigated a robust, biodegradable hydrogel synthesized from dopamine and gelatin. This gel is obtained by the oxidation of dopamine dissolved in water, after which the resulting quinone compound automatically undergoes self-polymerization. The oxidized dopamine subsequently undergoes Schiff base and Michael addition reactions with gelatin, such that the exposed gelatin surface cross-links to generate a continuous hardened hydrogel film. Because gelatin transitions between sol and gel states with changes in temperature, two- and three-dimensional structures could be obtained from the gel state. This bio-inspired interfacial cross-linking reaction provides a simple means of forming complex morphologies and represents a promising technique for bio-applications.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which emerged in December 2019 and caused the coronavirus disease 2019 (COVID-19) pandemic, took the world by surprise with an unprecedented public health emergency. Since this pandemic began, extraordinary efforts have been made by scientists to understand the pathogenesis of COVID-19, and to fight the infection by providing various preventive, diagnostic and treatment opportunities based on either novel hypotheses or past experiences. Despite all the achievements, COVID-19 continues to be an accelerating health threat with no specifically approved vaccine or therapy. This review highlights the recent advances in COVID-19 infection, with a particular emphasis on nanomedicine applications that can help in the development of effective vaccines or therapeutics against COVID-19. A novel future perspective has been proposed in this review based on utilizing polymersome nano-objects for effectively suppressing the cytokine storm, which may reduce the severity of COVID-19 infection.

The electrostrictive response of soft elastomers with the same stiffness, strongly depends on their chemical nature and their typically multiphase microstructure. Moreover, some elastomers exhibit a strongly time dependent electrostriction over tens of minutes, and up to now, no theoretical approach has been proposed to analyze experimental data on local parameters like the dielectric constants, conductivities and viscoelastic moduli of these composite-like materials. We consider the phenomenon where the deformation of a polymeric sample between two electrodes is proportional to the square of the applied field, which is known as electrostriction. The electrostatic attraction of charged electrodes is Maxwell electrostriction. In cases, such as block co-polymers with phase separation, the observed electrostriction reaches magnitudes more than 10 times higher than those achieved via the Maxwell process. Phenomenological analyses of experimental data are usually performed but few physical have been proposed to explain the difference. Therefore, we analyze the electric forces inside a composite-like polymer and estimate the corresponding deformation. Using data sets for polyurethane-based materials that exhibit phase separation during their processing, we propose a microstructural model corresponding to a composite where spherical particles randomly fill a matrix. The particles and matrix exhibit different values of physical parameters such as the (i) dielectric constant and electrical conductivity, which determine the local electric field and (ii) viscoelastic modulus, which determine the local stiffness. Because the phases are different, the electric field is not homogenous and the field gradient generates forces around the interfaces. Developing a 2D model, we compare simulation results to experimental literature and other modeling approaches, and discuss them in detail. The polarization forces are found to be responsible for 20% of the deformation in a material with 35% inhomogeneity. Though the time constants are consistent with experimental data, their contribution is smaller than the Maxwell contribution, and therefore other mechanisms are involved in the large electromechanical activity of polymers like polyurethanes.

Microorganisms form strong communities known as biofilms, which are ubiquitous in both natural and artificial environments and lead to problems such as health hazards and energy loss. The most effective solution against biofouling is to prevent the initial adhesion of the microbial cells to the material surface. This paper reports the fabrication of slippery liquid-infused porous surfaces (SLIPSs) through a simple method and the antibiofouling properties of these surfaces against microorganisms. The principle of these surfaces is inspired by Nepenthes, which are pitcher plants. SLIPSs can be easily and inexpensively generated through the breath figure method and ultrasonic processing. The developed silicon oil-infused substrate exhibited a low fall angle and antifouling characteristics. The results suggest that the proposed simple method can be used to successfully generate an antibiofouling substrate.

The sluggish kinetics of the oxygen reduction reaction (ORR) requires highly effective and stable electrocatalysts to boost the reaction. However, conventionally used Pt-based catalysts are expensive and suffer from long-term stability. The present work provides some interesting insights into using heteroatom-doped carbon electrocatalysts prepared from marine biomass cellulose nanocrystals as potential electrocatalysts for an efficient ORR. The proposed simplistic approach provides a substantial synthetic platform for applying an easily obtained bio-derived highly crystalline cellulose material to energy conversion and storage systems.

Honeycomb-patterned polymer films prepared by the breath figure method exhibit unique shape features. These films have potential in various applications, but functional materials are rarely embedded into the arrayed cavity. Here, a photoswitchable function of a compartmented nematic liquid crystal (NLC) in a honeycomb array is proposed. Surface segregation and liquid crystal self-assembly processes cover curved honeycomb walls of polystyrene (PS) with a high-density polymer brush of an azobenzene side chain liquid crystalline polymer (SCLCP), producing honeycomb polymer films with isolated cavities. Spherical confinement of the cavities with the SCLC brush provides a bipolar nematic director (planar anchoring), whereas UV light irradiation induces a radial configuration (homeotropic anchoring) of NLC droplets. Photoisomerization of azobenzene UV and visible light irradiation repeatedly induces a photoswitchable change between the bipolar and radial modes.

The geometrical control of micronetwork structures ((Formula presented.) NSs) formed by endothelial cells is an important topic in tissue engineering, cell-based assays, and fundamental biological studies. In this study, (Formula presented.) NSs are formed using human umbilical vein endothelial cells (HUVECs) by the coculture of HUVECs and human mesenchymal stem cells (MSCs) confined in a honeycomb-patterned poly-l-lactic acid film (honeycomb film (HCF)), which is a novel cell culture scaffold. The HCF is produced using the breath figure method, which uses condensed water droplets as pore templates. The confinement of the HUVECs and MSCs in the HCF along with the application of centrifugal force results in (Formula presented.) NS formation when the pore size is more than 20 (Formula presented.) m. Furthermore, (Formula presented.) NS development is geometrically restricted by the hexagonally packed and connected pores in the horizontal direction of the HCF. Network density is also controlled by changing the seeding density of the HUVECs and MSCs. The threshold pore size indicates that (Formula presented.) NSs can be formed spontaneously by using an HCF with a perfectly uniform porous structure. This result provides an important design guideline for the structure of porous cell culture scaffolds by applying a blood vessel model in vitro.

Metamaterials, subwavelength nanostructured materials, can exhibit novel optical properties such as a negative index of refraction. Dielectric core-nanoparticle satellite clusters, termed "metamolecules," can have strong optical magnetic resonances in the visible wavelength range-a requirement to achieve negative refractive index materials. However, achieving the desired photonic properties is challenging due to limited control in forming the metamolecule structures. Here, polystyrene (PS) core-gold nanoparticle (AuNP) satellite metamolecules with highly ordered single layers (monolayers) of AuNPs are fabricated and single particle spectroscopy, electron tomography structural measurements, and electrodynamics simulations are conducted to study the photonic properties of metamolecules constituted of approximate to 100 AuNPs. The simulated and experimental spectra of the many metamolecules studied, including excitation with azimuthally and radially polarized light, are in excellent agreement. It is shown that the scattering properties of the metamolecules are dominated by the AuNPs near the "equator" of the cluster, and that backscattering is strongly suppressed when different multipolar modes (e.g., dipolar and quadrupolar) of electric or optical magnetic character have comparable intensity due to the pi-phase shift of their scattering. Both the optical excitation fields and the ordering of the nanoparticles within metamolecules affect their optical excitation and scattering properties, providing new insights into designing novel photonic metamaterials.

Development of innovative polymer electrolytes that simultaneously possesses high mechanical stiffness as well as liquid-like ion motions is desirable for safer lithium-ion secondary batteries. Herein, bifunctional poly(ethylene glycol) diacrylate (PEGDA) based cross-linked network polymer electrolytes (PE) plasticized by tetraglyme at various lithium salt concentrations were fabricated via a solvent-free UV-curing process using a photo-initiator, 2,2-dimethoxy-2-phenylacetophenone (DMAP). The outstanding results demonstrate potential for safer high-performance rechargeable lithium-ion batteries.

Magnesium silicide (Mg2Si) is one of the few thermoelectric materials that is composed of high Clark number elements and exhibits an optimum temperature near 700 K. The advantage of Mg2Si is that it is composed of universal elements and can be synthesized at low cost. However, it has the disadvantage of low efficiency in converting heat flow to electricity due to its high thermal conductivity. In this paper, Mg vapor annealing of silica-coated 1,2-polybutadiene honeycomb films enables the formation of a Mg2Si honeycomb supported by amorphous carbon. The annealing temperature should be greater than 998 K to obtain Mg2Si honeycombs, and we confirmed through detailed chemical analysis that a silica layer can be converted to a Mg2Si layer via formation of Si. Furthermore, the honeycomb structure eventually reduced the thermal diffusivity even though only a single layer of the honeycomb structure formed on the surface. The obtained Mg2Si honeycombs are good candidates for effective and low-cost thermoelectric materials for use in high-temperature applications.

Thin polymer films with perpendicularly aligned nanocylinder arrays were fabricated from block copolymers of poly(N-dodecylacrylamide) and poly(ethylene glycol) (pDDA-b-PEG). Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize pDDA-b-PEG block copolymers with different degrees of polymerization (DP) of DDA by using trithiocarbonate-substituted PEG as the macrochain-transfer agent (PEG-CTA). Thin films of pDDA-b-PEG were prepared by using a spin-coating method, and their structures were characterized by atomic force microscopy (AFM) and X-ray diffraction (XRD). AFM phase images of the thermally annealed films showed a featureless surface irrespective of the DP of DDA. Subsequent annealing of the films under humid conditions induced nanophase separation of the pDDA blocks. One-dimensional XRD patterns suggested that the pDDA block formed a highly oriented lamellar structure, wherein the dodecyl side chains are perpendicularly aligned relative to the substrate. AFM images of the films annealed under humid conditions exhibited a hexagonally aligned PEG nanocylinder array. The results of two-dimensional grazing angle incident small-angle X-ray scattering (2D GI-SAXS) and cross-sectional transmission electron microscopy (TEM) image suggested a perpendicular alignment of the nanocylinders throughout the film. The diameter of the nanocylinders (similar to 8 nm) was determined by AFM and scanning transmission electron microscopy (STEM). In their entirety the results of this study suggest that the vertical orientation of the PEG nanocylinders relative to the substrate surface is induced by the orientation of the lamellar pDDA. Nanophase separation in comb-shaped polymers, in combination with a simple pDDA block and humid annealing, thus offers a unique preparative method for self-assembled structures in polymer films.

Wettability control of porous materials is significant in lateral flow immunoassay, microfluidic systems, microdroplet manipulation, and so on. In this report, formation of metal oxide layers on self-organized polymer honeycomb films to control surface wettability by simple sol-gel coating and UV-O-3 treatment was demonstrated. By the combination of bottom-up and topdown processes, silica thin layers can be formed by retaining their original three-dimensional honeycomb structures. Furthermore, photopatterning of metal oxides on honeycomb films can be achieved by UV irradiation through photomasks. Site-selective wettability control of honeycomb films was realized by patterning silica layers on the surface of the film.

A simple pathway for the fabrication of real moth eyelike patterned (MEP) polymer film with a double-layered nano/microhierarchical structure is demonstrated through a solid/liquid interfacial reaction at atmospheric conditions. A convex-structured polyvinyl alcohol (PVA) film containing CdCl2 was first fabricated using a self-organized honeycomb-patterned porous film as a template. The CdCl2/PVA convex film was immersed into Na2S/ethanol solution to facilitate the reaction between CdCl2 and Na2S at the solid/liquid interface, which led to the functionalization of CdS nanoparticles in the convex-structured PVA film. The tunable introduction of interfacial reaction resulted in the formation of a CdS moth eyelike nanoarray on the top surface of the PVA convex microarray, which mimicked the real moth eye (PVA-CdS MEP). PVA-CdS MEP film with a double moth eyelike structure showed improved antireflective property in comparison with flat and convex-structured PVA films. The PVA-CdS MEP film showed photoresponse under simulated solar light radiation and flexible duration after 500 cycles of folding.

The orientation effect of sepiolite natural clay, a needle-shaped nanoparticle, in a polymer matrix was investigated. Uniaxial drawing was performed on polymer-based nanocomposites containing organo-modified sepiolite, achieving uniform dispersion in the crystalline polymer by modifying the surface with organic molecular chains. Fluorinated polymer was used as the matrix, and sepiolite was modified using fluorinated chains. High-temperature drawing was conducted to increase the density of amorphous chains in the fluoropolymer. Observations confirmed the orientation of the nanofiller in the drawing direction. When the filler content was intentionally increased, it was as if it were a nanosized mille-feuille. As a result of 5x drawing, a 20% improvement in crystallinity was calculated. Small-angle X-ray scattering (SAXS) analysis showed a 32 angstrom increase in long-period values. When high-drawing was conducted, some amorphous parts transformed into crystals, and the difference in electron densities between the two regions widened, increasing the long-period value while decreasing the SAXS intensity. The crystallization temperature increased by 1.8 degrees C, and the Young's modulus calculated from the strain-stress curve showed a nearly 4x increase. The mechanical strength doubled when the neat fluoropolymer was drawn five times. This provides a clear understanding of the enhancement behavior of the structural and physical properties of a uniform dispersible polymer/needle nanoparticle nanocomposite using uniaxially oriented nanofillers.

We herein report that sulfur and nitrogen co-doped hollow spherical carbon particles can be applied to oxygen reduction reaction (ORR) electrocatalysts prepared by calcination of polydopamine (PDA) hollow particles. The hollow structure of PDA was formed by auto-oxidative interfacial polymerization of dopamine at the oil and water interface of emulsion microdroplets. The PDA was used as the nitrogen source as well as a platform for sulfur-doping. The obtained sulfur and nitrogen co-doped hollow particles showed a higher catalytic activity than that of nonsulfur-doped particles and nonhollow particles. The high ORR activity of the calcined S-doped PDA hollow particles could be attributed to the combination of nitrogen and sulfur active sites and the large surface areas owing to a hollow spherical structure.

Underwater highly bubble and oil-repellent surfaces were prepared based on honeycomb- and pincushion-structured films prepared by breath figure technique and post modifications including UV-ozone treatment and peeling the top layer. Furthermore, bubble generation from the plastron-like honeycomb gas chamber by attaching oil droplet onto the surface of honeycomb films was first observed. Both controlling gas bubbles and oil droplets underwater are important issues in the field of microfluidics since they are useful and may solve the maleficence to liquid transportation in narrow microchannels.

Porous honeycomb-patterned (HCP) polystyrene (PS) film was pore-selectively functionalized by carboxylic acid group and modified by thermo-responsive poly (N-isopropylacrylamide) (PNIPAAm) to extend the application of HCP polymer films. The carboxylic acid functionalized film was obtained by a reactive breath figure method by casting a formylated PS (PS-CHO) solution under aqueous humid conditions containing oxone, which oxidized aldehyde into carboxyl acid at the interface of a water droplet/polymer solution accompanying an interfacial reaction. The fabricated film was reacted with amine-terminated poly (N-isopropylacrylamide) in aqueous solution for the pore-selective PNIPAAm modified HCP film. Temperature-dependent pore-surface morphology and wettability of the film were observed by scanning electron microscopy and contact angle measurement analysis after immersing into the water at below and above the lower critical solution temperature of PNIPAAm. The increase of temperature induced the pore-surfaces of the film to a higher rugged surface morphology and more hydrophobicity. The temperature-dependent capture ability of Ag nanoparticles in the pore-selective PNIPAAm modified HCP film was studied by immersing the film in aqueous solution containing Ag nanoparticles at 25 degrees C and 40 degrees C, which resulted in a higher capturing at higher temperature.

In this study, we have developed a novel electrochemical device (IDEA-Bio-LSI) incorporating interdigitated electrodes array (IDEA) and a LSI-based amperometric device (Bio-LSI) for high speed (4-200 ms) and selective imaging of an analyte diffusion and cellar activities such as dopamine release. The amplification factor (eta(amp)) and capture efficiency (CE) of IDEA of the device were 2.17 and 0.767, respectively. Compared with previously reported IDE based imaging sensor, the acquisition speed of the present device to acquire one image was improved up to 50-250 times. In addition, the dopamine release from PC12 spheroids in the presence of ascorbic acid was successfully obtained by using the IDEA-Bio-LSI. Therefore, IDEA-Bio-LSI can apply to rapid analyte diffusion biological events such as release of dopamine release.

Biomimetic synthetic functional materials are valuable for a large number of practical applications with improved or tunable performance. In this paper, we present a series of mussel-inspired biomimetic catechol-containing copolymers synthesized from dopamine methacrylamide (DMA) and 2-(2-ethoxyethoxy)ethyl acrylate (EEA) and abbreviated as poly(PDMA-PEEA). The successfully synthesized adhesive polymers allow adhering polytetrafluoroethylene (PTFE) and were used for coating PTFE particles in organic solvent and re-dispersion in an aqueous medium. Adhesive polymer coated PTFE particles were efficiently used as a nanoreactor for generating silver (Ag) metal nanoparticles (NPs).

A new class of Pt-free catalysts was designed that included molecular iron phthalocyanine (FePc) derivatives, namely, iron azaphthalocyanine (FeAzPc) unimolecular layers (Fe AzULs) adsorbed on oxidized multiwall carbon nanotubes (oxMWCNTs). FeAzPcs were dissolved in organic solvents such as dimethyl sulfoxide (DMSO), and catalytic electrodes modified with molecularly adsorbed FeAzPcs were successfully prepared. The optimized composition of the catalytic electrodes was determined, and the electrodes exhibited superior activity for the oxygen reduction reaction (ORR) and better durability than conventional FePc catalytic electrodes and commercial Pt/C due to the electron-withdrawing properties of the pyridinic nitrogen in FeAzPcs. The catalytic electrodes that were molecularly modified with FeAzPcs have higher activities than those composed of FeAzPc crystals and oxMWCNTs. To the best of our knowledge, among all of the conventional catalysts based on modified MWCNTs and oxMWCNTs, this catalyst exhibits the highest activity. Unlike other Pt-free catalytic electrodes, the Fe AzUL catalytic electrodes can be prepared by low-cost processing without pyrolysis and are therefore promising catalytic electrode materials for applications, such as polymer electrolyte fuel cells and metal-air batteries.

This Review examines recent developments in the morphological control of polymer microspheres fabricated via the phase separation of polymers as well as the alignment of functional nanoparticles inside microspheres prepared by so-called bottom-up synthesis techniques. Several methods for adjusting the internal and surface morphologies of polymer microspheres based on the phase separation of polymer blends and block copolymers are discussed, and the effects of microsphere size on phase separated structures and theoretical simulations of morphologies are also reviewed. The alignment of functional nanoparticles in phase separated polymer microspheres and applications of nanostructured and hybrid polymer microspheres are summarized.

Unique morphologies were found in binary and ternary polymer blended particles, including Ashura-type phase separation, which has three different polymer components on the particle surface. The morphologies of phase-separated structures in the binary polymer blended particles are discussed in terms of the surface tensions of the blended polymers. Structural control of ternary polymer blended particles was achieved based on the combination of polymers by examining binary polymer blended particles. A theoretical approach based on the Cahn-Hilliard equations gives identical morphologies with the experimental results. This work opens the way to creating polymer particles with sophisticated nanostructures by controlling their morphologies as predicted by theoretical simulations.

A method for fabricating polymer Janus particles with microring structures at their equators has been developed. This method allows gold nanoparticles and nanorods to be aligned and densely packed along the microrings.

Here we report the synthesis and electrocatalytic properties of polymer films containing nitrogen and iron. The films were prepared by calcination of polydopamine, polyethyleneimine and iron. The composite films were self-assembled at the air/water interface, and exhibited higher activity for the oxygen reduction reaction than glassy carbon or calcined polydopamine films. These results suggest that such calcined composite films have potential applications as cathodes in polymer electrolyte fuel cells.

The honeycomb-structured film has advantages such as high wettability and high surface area. This structure and properties are suitable for the capacitor electrode. In this study, the electrode structure is controlled by the synthesis of MnO2 nanoparticles using the breath figure method. The electrode performance was calculated by electrochemical measurements. As a result, the capacitance value was 100.5 F/g at 1 mV s(-1), which was improved 2.7 times as compared with that without structure control.

Janus particles, particles that have two distinct aspects on their surface or interiors, have attracted much attention due to their potential for application. For the application of Janus particles to high-resolution displays, and as light sources for optical circuits and fluorescent probes, the Janus particles should be nanosize to ensure high-resolution display and analysis, responsive to external stimuli, and highly fluorescent. However, it is still a challenging issue to develop such highly fluorescent nanoscale Janus particles and control their alignment. Magnetoresponsive Janus particles, of which the orientation can be controlled by an external magnetic field, are prepared by the simple introduction of polymer-coated magnetic nanoparticles (NPs) into the hemispheres of Janus particles. If these magnetoresponsive Janus particles can be combined with a strong fluorescence system, then they could be ideal candidates as components of the previously mentioned applications. In the present study, Janus particles are prepared with a fluorescent dye and gold nanoparticles (Au NPs) on one side. The optical properties of the resulting particles are assessed and discussed. Furthermore, the response of composite Janus particles containing dyes, Au NPs, and iron oxide NPs to an external magnetic field is discussed.

Since neurotransmitters play critical roles in nervous systems, the imaging techniques that can visualize them are needed. This communication describes the development of a method for simultaneous imaging of dopamine (DA) and glutamate (Glu), typical neurotransmitters, using enzyme-modified large-scale integration (LSI)-based amperometric devices, referred to "Bio-LSI". The DA was detected by using direct electrochemical oxidation while Glu was measured by using an indirect electrochemical reaction involving glutamate oxidase (GluOx)/horseradish peroxidase (HRP) and osmium (Os) polymer-modified electrodes. The Os-HRP polymer was modified on designated sensor electrodes through electrodeposition. The selective and simultaneous imaging of neurotransmitters such as DA and Glu was achieved by applying the enzyme-modified Bio-LSI.

Metal nanoparticle clusters are regarded as metamaterials, and dispersions of nanoparticle clusters are regarded as metafluids. Surface-enhanced Raman scattering (SERS) from molecules adsorbed on the nanoparticle clusters is one of the notable properties of metafluids. SERS is expected to permit the realization of single-molecule detection in chemical and biological samples, especially cells and tissues. However, most SERS measurements have been done on substrates; local information on cells and tissues have been hard to obtain. SERS active particles can be used to measure the local information on cells. To analyze biological samples using SERS, the SERS substrate should be excitable in the near-infrared (NIR) region to ensure high transparency in biological tissues. Furthermore, transporting the SERS particles to the desired position is crucial for obtaining high resolution. Sizes of SERS-active particles also affect to the resolutions. In this report, gold nanoparticle clusters based on polymer core-shell particles incorporating magnetic Fe3O4 nanoparticles were prepared via a self-assembly method. Structures, LSPR absorption, SERS signals, magnetic responsibility of prepared particles were analyzed by electron microscope, UV-vis spectrum, Raman measurement, and optical microscope observation under magnetic flux, respectively. The enhancement factor of the SERS signal was determined by the size of composited gold nanoparticles. Furthermore, the migration direction of the gold nanoparticle cluster composite particles in aqueous media was successfully controlled by the application of an external magnetic field.

Nanoparticles with structural or chemical anisotropy are promising materials in domains as diverse as cellular delivery, photonic materials, or interfacial engineering. The surface chemistry may play a major role in some of these contexts. Introducing reactivity into such polymeric nanomaterials is thus of great potential, yet is still a concept in its infancy. In the current contribution, a simple nanoprecipitation technique leads to nanoparticles with diameters as low as 150 nm and well-defined reactive surface patches of less than 30 nm in width, as well as surface-reactive flat, disc-like nanoparticles with corresponding dimensions, via an additional crosslinking/delamination sequence. To this aim, chemically doped block copolymers (BCPs) are employed. Control over morphology is attained by tuning preparation conditions, such as polymer concentration, solvent mixture composition, and blending with non-functional BCP. Surface reactivity is demonstrated using a modular ligation method for the site-selective immobilization of thiol molecules. The current approach constitutes a straightforward methodology requiring minimal engineering to produce nanoparticles with confined surface reactivity and/or shape anisotropy.

The breath figure method, which is used to form porous films from water droplet templates, has attracted considerable interest because it is simple and applicable to a wide variety of materials. Research on breath figures took off after the 2000s, accompanied by new polymer synthesis methods, fabrication methods, and a wide variety of applications. There are several comprehensive reviews of the applications of the porous films, which are usually called 'honeycomb films' because their hexagonally packed porous structure resembles honeycombs. However, new materials, progress in preparation technologies for controlling nano- and microstructures, and large-area fabrication are still areas that require further research. Furthermore, new applications of honeycomb films have emerged. In this review, the recent development of honeycomb films prepared by the breath figure techniques and their numerous applications are summarized. The production of honeycomb films can be performed on an industrial scale, greatly broadening their possible applications in areas such as optics, photonics, surface science, biotechnology, and regenerative medicine. Present problems and future perspectives are also discussed.[GRAPHICS].

The development of hybrid films containing binary nanoparticles is one of the current key objectives in nanotechnology. Different nanoparticles dispersed in a polymer matrix exhibit diverse functions, and their properties are influenced by the interplay between the nanoparticles. The poly(vinyl catechol)-block-polystyrene (PVCa-b-PSt) block copolymer containing a catechol group, which is inspired by the adhesive protein found in the mussel foot, is an attractive platform for the coassembly of binary nanoparticles because the catechol group has various desirable properties, including the ability to coordinate metal oxides and reduce metal ions. In the fabrication of hybrid materials based on PVCa-b-PSt thin films, it is challenging to control the microdomain morphologies and the nanoparticle assembly process. In this work, we investigate the impact of solvent vapor annealing on microphaseseparated nanostructures in lamellae-forming PVCa-b-PSt. We show that a fast solvent vapor annealing in a tetrahydrofuran atmosphere for 10 min induces the formation of perpendicularly oriented lamellar structures within PVCa-b-PSt thin films. We also propose a stepwise approach to create binary nanoparticles coassemblies in PVCa-b-PSt thin films. In the first step of this process, we exploit the metal-coordination properties of PVCa-b-PSt catechol groups to drive the directed self-assembly of magnetite (Fe3O4) nanoparticles for the preparation of magnetic hybrid thin films. The Fe3O4 nanoparticles are dispersed and localized mainly within PVCa microdomains of the lamellar PVCa-b-PSt thin films. In the second step, the catechol group reduces the AS' ion in the magnetic hybrid thin films, which leads to the formation of hybrid thin films containing Ag nanoparticles. Plasmonic Ag nanoparticles and magnetic Fe3O4 nanoparticles coassemble in the PVCa microdomains. The resulting plasmonic/magnetic hybrid thin films exhibit an enhanced magneto-optical Kerr effect because of the localized surface plasmon resonance of the Ag nanoparticles near Fe3O4 nanoparticles within the PVCa microdomains. Such magneto-optical (MO) properties make the hybrid thin films interesting for imaging of magnetic fields and MO devices. Our results indicate that PVCa-b-PSt is a promising platform for developing well-ordered hybrid thin films containing different nanoparticles.

Hybridized microparticles composed of mesoporous manganese dioxide (MPMO) core and fullerene C-60 nanocrystal (NCs) shell were fabricated by co-reprecipitation method. Double layer capacitance as well as fast surface redox reaction of MPMO contributes to increase the energy density, whereas C-60 NCs contributes to the reduction of IR loss to enhance the power density. The coating of MPMO with C-60 NCs resulted in a greatly improved pseudocapacitor performance, owing to the improved conductivity to allow fast charging/discharging.

Annealing of block copolymers has become a tool of great importance for the reconfiguration of nanoparticles. Here, we present the experimental results of annealing block copolymer nanoparticles and a theoretical model to describe the morphological transformation of ellipsoids with striped lamellae into onionlike spheres. A good correspondence between the experimental findings and predictions of the model was observed. The model based on finding the steepest direction of descent of an appropriate free energy leads to a set of Cahn-Hilliard equations that correctly describe the dynamical transformation of striped ellipsoids into onionlike spheres and reverse onionlike particles, regardless of the nature of the annealing process. This universality makes it possible to describe a variety of experimental conditions involving nanoparticles underlying a heating process. A notable advantage of the proposed approach is that it enables selective control of the interaction between the confined block copolymer and the surrounding medium. This feature endows the model with a great versatility to enable the reproduction of several combined effects of surfactants in diverse conditions, including cases with reverse affinities for the block copolymer segments. A phase diagram to describe a variety of morphologies is presented. We employ the relationship between the temperature-dependent Flory-Huggins parameter and the width of the interfaces to account for changes in temperature due to the heating process. Simulation results correctly show how the transformation evolves as the temperature increases. This increment in temperature corresponds to progressively smaller values of the interfacial width. We anticipate that the proposed approach will facilitate the design and more precise control of experiments involving various kinds of annealing processes.

Conventional organic pH indicators are widely used for chemical synthesis and analysis based on change of pi conjugation length depending on pH values. However, there are a few organic pH indicators for strong acid conditions, because organic compounds are usually decomposed at extreme low pH. Tetra-2,3-pyridoporphyradine (TPP) has high chemical stability and crystallinity, and its nano-crystal is widely used as stable pigments. ZnTPP exhibits red fluorescence, but ZnTPP crystals don't exhibit fluorescence due to concentration quenching. In this paper, we show a UV-assisted synthesis of ZnTPP nano-crystals and application for fluorescence pH indicator at extreme low pH condition by quaternization of ZnTPP nano-crystals. ZnTPP crystals were successfully synthesized and then dispersed into 1 to 10 M HCl aq. UV-Vis and fluorescence spectroscopy revealed that absorption and fluorescence change were observed depending on HCl concentrations at extreme low pH conditions due to quarternization of ZnTPP and dissolution of ZnTPP nano-crystals. These results indicate that ZnTPP nano-crystals can be used for fluorescence pH indicators at extreme low pH.

Catechol moieties, which are found in mussel-adhesive proteins, allow the interaction of various kinds of materials that results in substantial adhesion to a wide variety of materials and in the reduction of metal ions to solid metals. Various types of catechol-containing polymers mimicking adhesion and reduction properties have been reported, however, due to its reactivity to a wide variety of functional groups, only a few reports about the formation of block and sequence controlled copolymers containing catechol groups. This is the first report about the synthesis of triblock copolymers containing catechol groups by reversible-addition fragmentation transfer (RAFT) polymerization. The synthesized triblock copolymer forms a core-shell cylinder (CSC) phase-separated structure, in which PVCa domains located the surface of cylinders, and it works as a template for silver nanoparticle arrays and a proton conductive channel. Since triblock copolymer has broader latitude to form phase-separated structures, the triblock copolymer containing catechol groups can be suitable for templates of inorganic nanoparticle arrays.

Highly ordered porous films whose pore size ranges from submicron to micron scale have always been an extensive area of research due to their broad range of application to photonic crystals, cell culturing scaffolds, filtration and separation membranes, just to name a few. However, the fragile nature of such a functional porous film has hindered its implementation to advanced uses. Inspired by the hierarchic structure in nature which offers both robustness and functionality, we created in a single fabrication step a mesh-reinforced hierarchic perforated honeycomb film with highly ordered micron pores using the breath figure method. By using the elastomer 1,2-polybutadiene as the material for the film in the combination of the mesh grid, the pore size of the obtained film can be tuned upon stretching. Tubular structures made from the mesh-reinforced hierarchic perforated porous honeycomb film with tunable pore size have been demonstrated.

The aim of this research is realizing a high resolution and a fast color switching of electronic papers. In this report, we realized basis of electric papers comprised on magnetic Janus particles was established. Colored and magnetic Janus particles were successfully prepared, and magnetic Janus particles were introduced into honeycomb matrices. Introduced magnetic Janus particles quickly respond to an external magnetic field.

Here we report on the flattening of water droplets using an ultrathin membrane of autopolymerized polydopamine at the air/water interface. This has only been previously reported with the use of synthetic or extracted peptides, two-dimensional designed synthetic peptide thin films with thicknesses of several tens of nanometers. However, in the previous study, the shape of the water droplet was changed irreversibly and the phenomenon was observed only at the air/water interface. In the present study, an ultrathin polydopamine membrane-stabilized droplet induced the flattening of a water droplet at the air/liquid and liquid/liquid interfaces because a polydopamine membrane was spontaneously formed at these interfaces. Furthermore, a reversible transformation of the droplet to flat and dome shape droplets were discovered at the liquid/liquid interface. These are a completely new system because the polydopamine membrane is dynamically synthesized at the interface and the formation speed of the polydopamine membrane overcomes the flattening time scale. These results will provide new insight into physical control of the interfacial shapes of droplets.

Metal phthalocyanines (PCs) and their derivatives (PCDs) have been considered for applications in color filters, photovoltaic cells, and photodynamic therapy, owing to their unique optical properties, high chemical and thermal stabilities, and good electron mobility. In addition, since the optical and electronic properties of metal PCDs are improved considerably by reducing their dimensions to the nanoscale, nanocrystals (NCs) of metal PCDs have received much attention. We have previously demonstrated the direct synthesis of CuPCs and ZnPCs in nanomicelles via the UV irradiation of various precursors. In the present study, metal PCDs having various p-conjugated sub-stituents were synthesized using a one-pot UV-assisted process. The resulting metal PCD NCs were found to form stable dispersions in an aqueous PEG solution and these dispersions exhibited significant visible light absorption from 500 to 800nm and high transparency at wavelengths in the non-absorption region.

The present report describes the preparation of asymmetric polystyrene-block-poly(t-butyl acrylate) (PS-b-PtBA) particles having virus-like surface structures. Submicron-sized virus-like particles composed of asymmetric polystyrene-block-poly(t-butyl acrylate) (PS-b-PtBA) diblock copolymer particles with a dot pattern on the surface were prepared successfully using a simple solvent evaporation process. Particle surface morphology was controlled by mixing hPS with hPS of varying molecular weights and amounts. These results indicate that the surface morphology of virus-like particles can be controlled using asymmetric diblock copolymers and homopolymers. Deprotection of t-butyl moieties led to the formation of daughter particles with a size in the range of tens of nanometres. This process allows the development of new classes of functional particles useful for immunological diagnosis, drug delivery, and nanoscale-assembled architectures.

Microfluidic devices, which can continuously fabricate single emulsion with monodispersed droplets having a pore diameter of more than 100 mu m in large numbers, can be applied to manufacture ordered macroporous films. 3D ordered macroporous films with a diameter of more than 100 mu m can be fabricated using ordered arrays of the monodispersed droplets as templates of the macropores, which are self-assembled in the space between two parallel flat glass plates. As the gap between the glass plates increases, the number of the layer increases. Furthermore, in the case with two or more layers, the lattice structure of the macroporous films also changes due to the confinement effects.

The adhesion of bubbles underwater remains the greatest cause of malfunctions in applications such as microfluidics, medical devices, and heat exchangers. Recently the combination of oxidization and peeling the top layer of self-organized honeycomb films with an adhesive tape resulted in the formation of an ultra-bubble-repellent and pillared polymer surface structure. However, the fabrication of honeycomb films on the inner, surface of tubes and the formation of structured hydrophilic textures by peeling the top layer of honeycomb films still remain problematic., In this report, a simple fabricatinn technique for producing a honeycomb-pattemed polymer film on the interior of a: tube by dip-coating a polymer solution and, blowing humid air in the tube is described Furthermore, an ultra-bubble, repellent dimple-arrayed structure was fabricated by applying ultrasonicatiorcto the honeyconib structure formed on the interior surface of the tubes.

This report describes the preparation of ultrathin films possessing unusual fingerprint-like morphologies for poly(vinyl catechol-block-styrene) (PVCa-b-PSt) at the air-water interface by simply mixing a solution into water followed by solvent evaporation. Structural analysis and comparison with typical surface micelles of amphiphilic diblock copolymers indicated that precipitation and micelle aggregation played a significant role in the formation and unusual microphase separation of PVCa-b-PSt ultrathin films. In addition, the interior structures of the ultrathin films could be adjusted by adding homo-polystyrene (hPSt). Silver nanoparticle arrays were formed by immersing ultrathin films in aqueous AgNO3 and a microphaseseparated structure in the ultrathin films could act as a template for the arrays.

Size-controlled metal nanoparticles (NPs) were spontaneously formed when the amphiphilic diblock copolymers consisting of poly(vinyl catechol) and polystyrene (PVCa-b-PSt) were used as reductants and templates for NPs. In the present study, the proton conductivity of well-aligned lamellae structured PVCa-b-PSt films with Ag NPs was evaluated. We found that the proton conductivity of PVCa-b-PSt film was increased 10-fold by the addition of Ag NPs into the proton conduction channels filled with catechol moieties. In addition, the effect of humidity and the origin of proton conductivity enhancement was investigated.

The three-dimensional (3D) confinement effect on the microphase-separated structure of a diblock copolymer was investigated both experimentally and computationally. Block copolymer nanoparticles were prepared by adding a poor solvent into a block copolymer solution and subsequently evaporating the good solvent. The 3D structures of the nanoparticles were quantitatively determined with transmission electron microtomography (TEMT). TEMT observations revealed that various complex structures, including tennis-ball, mushroom-like, and multipod structures, were formed in the 3D confinement. Detailed structural analysis, showed that one block of the diblock copolymer slightly prefers to segregate into the particle surface compared with the other block. The observed structures were further elaborated using cell dynamics computer simulation. (C) 2016 Wiley Periodicals, Inc.

Porous polymer materials prepared from biodegradable polymers have received considerable attention due to their potential as cell culture scaffolds for tissue engineering. Porous materials are generally sterilized by autoclaving prior to use as cell culture scaffolds to avoid unexpected biological infection. However, the melting point of biodegradable polymers is typically lower than the temperature used in autoclave sterilization. Here, the preparation of honeycomb films comprising a poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) stereo complex is described and their thermal stabilities are evaluated. The hierarchic photochemical patterning of PLLA/PDLA stereo complex honeycomb-patterned films by UV-O-3 treatment is also demonstrated.

Control of the incorporation behavior of Au nanoparticles grafted with polystyrene (PS) in an ABC triblock terpolymer composed of PS, polyisoprene (PI) and poly(methyl methacrylate) (PMMA) with double-helical morphology was investigated by transmission electron microtomography and three-dimensional structural analysis. The assemblies in the microdomains were controlled by varying the molecular weight of the PS molecules grafted on the Au nanoparticles. For PS-grafted Au nanoparticles > 0.3 times the domain dimension of the PS microdomain in the poly(styrene-b-isoprene-b-methyl methacrylate) (SIM) film, the nanoparticles were located at the center of the PS microdomains to minimize the entropy loss of the PS segment of SIM. In contrast, Au nanoparticles < 0.2 times the domain dimension adsorbed preferentially to the interface of the PS and PI microdomains to reduce the interfacial tension between the nanoparticles and SIM. Intermediate-sized Au nanoparticles were uniformly distributed in the PS microdomains. The distribution of PS-grafted Au nanoparticles was explained by the entropic and enthalpic gains in the microdomains.

Block copolymer phase separation has been employed to form templates for the fabrication of nanoscale patterns of metals due to their characteristic size scales that range from several nanometers to tens of nanometers. In the present work, poly(vinyl catechol-block-styrene) PVCa-b-PSt synthesized with various compositions forms unique microphase-separated structures. Silver nanoparticles are spontaneously formed inside of the PVCa phases due to the reductive properties of the catechol moieties. The alignment and formation of silver nanoparticle arrays is successfully achieved without the need for high-temperature thermal treatment or chemical reduction processes. The present system can be applied to the formation of nanoparticle arrays with a wide variety of metals by control of their arrangement.

Colloidal assemblies of inorganic nanoparticles dispersed in liquid media hold particular promise for the creation of a unique class of functional materials with innovative applications. In the present report, "compound-eye"-like core-shell and Janus-type silica and amino-terminated 1,2-polybutadiene (PB-NH2) and polystyrene (PS) composite microspheres are successfully prepared by simply mixing an aqueous dispersion of silica particles into a tetrahydrofran (THF) solution of PB-NH2, and PB-NH2 and PS blends, followed by evaporation of the THF. This co-precipitation process provides a new approach for producing organic-inorganic composite particles without the need for surface modifi cation of the inorganic nanoparticles.

We numerically study a set of coupled Cahn-Hilliard equations as a means to find morphologies of diblock copolymers in three-dimensional spherical confinement. This approach allows us to find a variety of energy minimizers including rings, tennis balls, Janus balls and multipods among several others. Phase diagrams of confined morphologies are presented. We modify the size of the interface between microphases to control the number of holes in multipod morphologies. Comparison to experimental observation by transmission electron microtomography of multipods in polystyrene-polyisoprene diblock copolymers is also presented.

In this work, on-demand control of liquids is realized by using elastic, patterned omniphobic surfaces. This paves the way for novel microfluidics, as well as liquid harvesting, transportation, and manipulation technologies. Inspired by the lubricating properties of pitcher plants, microstructured 1,2-polybutadiene honeycomb and pincushion films obtained by self-organization are fluorinated by the ene-thiol reaction and infused with fluorinated lubricant to obtain omniphobic liquid-repellent surfaces. Unlike conventional bioinspired omniphobic surfaces, the liquid repellency of the fabricated surface can be programmed by changing the surface microstructures via patterning of the film. Furthermore, the elasticity of the omniphobic film is suitable for controlling the repellency through external stimuli. The method presented here for the fabrication of lubricant-infused omniphobic microstructured surfaces is also simple, cost-effective, and can be scaled for large area fabrication.

Metal phthalocyanines (PCs) are promising materials for various applications, including pigments, color filters, photovoltaic devices, and nonlinear optics, owing to their specific light-absorption properties and high stability to chemical and thermal degradation. Nanocrystals (NCs) of metal PCs have received much attention because the optical and electronic properties of metal PCs are improved considerably by decreasing the crystal size to the nanoscale. In this study, we demonstrated the direct synthesis of Cu and Zn PCs in nanosized micelles by irradiating precursors with UV light. The synthesized metal PC NCs were stably dispersed in water by adding polyethylene glycol as a stabilizer. The aqueous dispersions of PC NCs showed strong visible light absorption from 500 to 800 nm and high transparency at wavelengths in the non-absorption region.

A simple fabrication method is demonstrated for surface-enhanced Raman scattering (SERS)-active plasmonic nanoballs, which consisted of Au nanoparticles (NPs) and core-shell polystyrene and amino-terminated poly(butadiene) particles, by heterocoagulation and Au NP diffusion. The amount of Au NPs introduced into the core-shell particles increases with the concentration of Au NPs added to the aqueous dispersion of the core-shell particles. When the amount of Au NPs increases, closely packed, three-dimensionally arranged and close-packed Au NPs arrays are formed in the shells. Strong SERS signals from para-mercaptophenol adsorbed onto composite particles with multilayered Au NPs arrays are obtained by near-infrared (NIR) light illumination.

We proposed a block copolymer, poly(dihydroxystyrene-block-styrene) (PDHSt-b-PSt), that contains catechol groups in the side chains of PDHSt moieties. Since catechol groups automatically reduce silver (Ag) ions to theirmetallic state, the block copolymer was used as a reductant to synthesize organic-solvent-dispersive Ag NPs (NPs) stabilized with the block copolymer at room temperature. Ag NP sizes were controlled by changing molecular weights of PDHSt of the block copolymer.

We here describe a thin, highly stretchable transparent and molecular permeable porous electrode with a well-defined honeycomb structure fabricated by a combination of a bottom-up breath figure process and top-down sputtering of metals. Furthermore, the honeycomb electrode-hydrogel hybrids show higher durability, optical transparency, and electrical conductivity. The optical and electrical properties of the electrode, and its potential for use as a stretchable transparent electrode, are discussed.

Some kinds of snakes have micro-dimple arrays on their skins and show low frictional properties. Cost-effective and simple preparation methods of surfaces having micro-dimple arrays without burrs have been required. In this study, micro-dimple arrays were successfully prepared on aluminum plates and pipes by using honeycomb patterned porous films as wet etching masks. Resulting surfaces having 5 and 8 mu m dimple diameters show low frictional coefficients compared with polished surfaces at a fluid lubrication regime.

The adhesion of bubbles underwater remains the greatest cause of malfunctions in applications such as microfluidics, medical devices and heat exchangers. There is therefore an emerging need for ultra-bubble-repellent surfaces. Inspired by fish scales, which show high bubble repellency due to their hydrophilic nature and surface microstructures, we propose a novel method for preparing ultra-bubble-repellent surfaces by the hydrophilic treatment of self-organized microstructures. When in contact with air bubbles underwater, the artificial hydrophilic microstructured surfaces had a higher contact angle and a lower adhesion force than a flat surface. The mechanism leading to these properties is also investigated. Our method for the fabrication of ultra-bubble-repellent, hydrophilic, microstructured surfaces is simple and cost-effective, opening the way for its application in artificial devices, such as the inner surfaces of tubes, medical devices, and heat exchangers.

Microwell chip culture is a promising technique for the generation of homogenous spheroids. We investigated the relationship between the structure of the bottom surface of microwell chip and the properties of HepG2 spheroid. We developed a microwell chip, the bottom surface of which consisted of a honeycomb-patterned polymer film (honeycomb film) that had a regular porous structure (HF chip). The chip comprised 270 circular microwells; each microwell was 600 gm in diameter and 600 gm in depth. At the center of the honeycomb film, an area, 200 gm in diameter, was modified with collagen to facilitate cell adhesion. With the exception of the collagen-coated area, the entire microwell was modified with polyethylene glycol to eliminate cell adhesion. HepG2 cells formed uniform spheroids when cultured in the microwells of HF chip. Furthermore, the cells passed through the porous structure of honeycomb film and formed spheroids at its opposite side. The spheroid growth of HepG2 cells cultured in HF chip was greater than that when the cells were culture in a microwell chip, the bottom surface of which was made of poly-methylmethacrylate (PMMA chip). The albumin secretion activity of HepG2 spheroids in HF chip was equal to that in PMMA chip. These results indicate that the microwell bottom with a porous structure enhances the cell growth and maintains well the spheroid function. Thus, HF chip is a promising platform for spheroid cell culture. (c) 2014, The Society for Biotechnology, Japan. All rights reserved.

Recently, anisotropic colloidal polymeric materials including Janus microparticles, which have two distinct aspects on their surfaces or interiors, have garnered much interest due to their anisotropic alignment and rotational orientation with respect to external electric or magnetic fields. Janus microparticles are also good candidates for pigments in "twisting ball type" electronic paper, which is considered promising for next-generation flexible display devices. We demonstrate here a universal strategy to encapsulate inorganic nanoparticles and to introduce different such inorganic nanoparticles into distinct polymer phases in Janus microparticles. TiO2 and Fe2O3 nanoparticles were separately encapsulated in two different mussel-inspired amphiphilic copolymers, and then organic-inorganic composite Janus microparticles were prepared by simple evaporation of solvent from the dispersion containing the polymer and nanoparticle. These Janus microparticles were observed to rotate quickly in response to applied magnetic fields.

High-performance catalysts and photovoltaics are required for building an environmentally sustainable society. Because catalytic and photovoltaic reactions occur at the interfaces between reactants and surfaces, the chemical, physical, and structural properties of interfaces have been the focus of much research. To improve the performance of these materials further, inorganic porous materials with hierarchic porous architectures have been fabricated. The breath figure technique allows preparing porous films by using water droplets as templates. In this study, a valuable preparation method for hierarchic porous inorganic materials is shown. Hierarchic porous materials are prepared from surface-coated inorganic nanoparticles with amphiphilic copolymers having catechol moieties followed by sintering. Micron-scale pores are prepared by using water droplets as templates, and nanoscale pores are formed between the nanoparticles. The fabrication method allows the preparation of hierarchic porous films from inorganic nanoparticles of various shapes and materials.

Microwell chip culture is a promising technique for the generation of homogenous spheroids. We investigated the relationship between the structure of the bottom surface of microwell chip and the properties of HepG2 spheroid. We developed a microwell chip, the bottom surface of which consisted of a honeycomb-patterned polymer film (honeycomb film) that had a regular porous structure (HF chip). The chip comprised 270 circular microwells; each microwell was 600 gm in diameter and 600 gm in depth. At the center of the honeycomb film, an area, 200 gm in diameter, was modified with collagen to facilitate cell adhesion. With the exception of the collagen-coated area, the entire microwell was modified with polyethylene glycol to eliminate cell adhesion. HepG2 cells formed uniform spheroids when cultured in the microwells of HF chip. Furthermore, the cells passed through the porous structure of honeycomb film and formed spheroids at its opposite side. The spheroid growth of HepG2 cells cultured in HF chip was greater than that when the cells were culture in a microwell chip, the bottom surface of which was made of poly-methylmethacrylate (PMMA chip). The albumin secretion activity of HepG2 spheroids in HF chip was equal to that in PMMA chip. These results indicate that the microwell bottom with a porous structure enhances the cell growth and maintains well the spheroid function. Thus, HF chip is a promising platform for spheroid cell culture. (c) 2014, The Society for Biotechnology, Japan. All rights reserved.

Organic-inorganic composite microparticle having interior nanostructures is one of the promising materials for creating a novel class of functional materials. In this paper, we show a simple co-precipitation method for silica nanoparticles and polymer composite particles by mixing water with water dispersed silica nanoparticles into tetrahydrofran THF solution of amino-terminated poly(butadiene) (PB) and evaporation of THF. High loading of inorganic nanoparticles into polymer particles was achieved and this high loading of inorganic nanoparticles was also an advantage for creating highly porous polymer particles by removal of inorganic part with HF. Interior structures of composite particles can be controlled by phase-separation of polymers. (C) 2014 The Japan Society of Applied Physics

In this paper, we describe a novel concept for creating multicolor light reflectors by mimicking the surface structures of tiger beetle shells. We prepared dimpled and multilayered films containing thin black layers, which had multi-angle reflectivity, by embossing a silicone microlens array. The surface structuring caused the reflected light to be scattered at multiple angles and thus visible at different viewing angles. This scattering system increases the visibility of the biological surface colors and blends the reflected colors of tiger beetles. These results demonstrate that combining multilayered structures with surface structuring produces unique optical properties.

Polymer-inorganic nanoparticle (NP) composites are prepared by immersing preformed end-functionalized poly (butadiene) (PB) films, which have a lower glass transition temperature than room temperature, in an aqueous dispersion of Au NPs. Depending on the viscosity of the PB matrix, the Au NPs show different distributions in the end-functionalized PB matrix. In the high viscosity matrix, the Au NPs are immobilized at the surface of the end-functionalized PB, whereas in the low viscosity matrix, the Au NPs are incorporated into the matrix and are well dispersed. This incorporation of Au NPs occurs dynamically in three steps: (1) adsorption of the Au NPs on the surface of the PB matrix through electrostatic interactions; (2) stabilization of the Au NPs by the end functional groups of the PB molecules; (3) the diffusion of the Au NPs into the PB matrix because of the low viscosity of the matrix.

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We describe a method for creating robust and stable core-shell polymer microspheres decorated with inorganic (IO) nanoparticles (NPs) by a self-organization process and heterocoagulation using a mussel-inspired polymer adhesive layer between the IO NPs and the microspheres.

Polystyrene honeycomb scaffolds with different pore sizes were successfully fabricated by casting a polymer solution under humid conditions in order to investigate the effect of porous microtopography on hMSC differentiation. We have used honeycomb scaffolds to achieve the microtopography-induced differentiation of hMSCs. Honeycomb scaffolds led hMSCs to osteospecific and myospecific differentiations depending on the size of pores. This selective differentiation suggested that surface microtopography alone may be effective for using hMSCs in regenerative medicine and tissue engineering.

This paper reviews recent progress concerning polymeric self-assemblies in confined spaces, including phase-separated structures of polymer blends and block copolymers. Although a wide variety of polymer self-assemblies have been studied in terms of conventional parameters, such as blend ratio, interaction of constituent polymers, block ratio, and molecular weight, a series of unique structures appear when the systems are self-assembled under confined conditions. Due to the limited space for phase separation, the polymers in the confinement are frustrated, and the resulting morphologies are distinctly different from those formed in free space. We give an overview of experimental and theoretical studies of the frustrated morphologies. We begin by defining confinement with respect to dimensionality and surface properties, and then introduce methods for producing various shapes and sizes of three-dimensional confinement. Finally, we present morphological and application-oriented studies and discuss the prospects for this research area.

This study describes the formation of macro-scale defects of the honeycomb-patterned polymer film and we discovered two types of new line defects which differ from the defects reported in the past studies. We examined the formation mechanisms of the line defects and clarified two types of formation mechanisms of the "Divergent" mode line defects and the "Convergent" mode line defects caused by the "tectonics" of water droplet arrays on polymer solutions. The regions causing the macro-scale line defects are made clear in the phase diagram represented by the radius and the density of the micro-scale water droplets. In addition, the results of our calculations made it possible to theoretically predict the water droplet growth time for the water droplets to grow to the ideal size for uniform packing that is necessary for fabrication of the defect-free honeycomb-patterned polymer film. With the use of these techniques, A4-sized, defect-free, honeycomb-patterned polymer films can be fabricated.

Composite particles with varying morphologies composed of gold nanoparticles (Au NPs) and polymers were fabricated based on a combination of electrostatic interactions between the polymer particles and Au NPs and diffusion processes. The positively charged polymer particles were prepared from amino-terminated polystyrene (PS-NH2) and amino-terminated 1,2-polybutadiene (PB-NH2). Adsorption of citrate-stabilized Au NPs resulted in three different distribution states of Au NPs in the polymer particles, depending on the glass transition temperature (T-g) and molecular weight of the polymer. The adsorption of Au NPs onto PS-NH2 particles produced raspberry-like composite particle morphologies, while the NPs instead diffused into the PB-NH2 particles, since the T-g of PB-NH2 is below room temperature. The diffusion of Au NPs could be controlled by varying the molecular weight of the PB-NH2 and the diameter of the NPs, and both core-shell and amorphous distributions were successfully achieved.

Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair-and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

A simple preparation method has been developed for creating inorganic organic composite films by casting of soft poly(butadiene) (PB) particles and hard SiO2 particles. PB particles were successfully prepared by evaporation of a good solvent from the PB solution containing water as a poor solvent. After crosslinking PB and removal of SiO2 particles, an inverse opal structure can be formed. The size difference between PB and SiO2 particles critically determines the coassembling structures.

We describe here the first report for developing microphase-separated structures in poly(styrene-block-isoprene) (PS-b-PI) block copolymer nanoparticles by microwave annealing in a nonsolvent, water. A random structure in the nanoparticles successfully transformed to thermodynamically stable structures within several minutes though it takes several days by using the conventional thermal annealing process.

In this report, we show a simple route to fabricate Janus particles having magnetic nanoparticles inside them, which can respond and rotate along to magnetic fields. By solvent evaporation from the tetrahydrofran solution of polymer stabilized γ-Fe2O3 nanoparticles, polystyrene (PS), and polyisoprene containing water, aqueous dispersion of Janus microparticles were successfully prepared, and the γ-Fe2O 3 nanoparticles were selectively introduced into the PS phase. We demonstrate rotation and accumulation of Janus particles by using a neodymium magnet. © 2013 American Chemical Society.

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In this report, we show the preparation of honeycomb scaffolds for cell culturing by using "breath figure" method, and we found that their mechanical and topographical properties strongly affect the adhesion of fibroblasts. By photocross-linking of the poly(1,2-butadiene), the hardness of the honeycomb scaffold can be successfully controlled without any surface chemical changes, and detail modulus values of scaffolds were measured by atomic force microscopy. We found that only small numbers of the cells adhered on the softer honeycomb scaffolds, which has even higher modulus value than conventional gels, comparing with flat films and a hard honeycomb scaffold. These results indicate that the elastomeric honeycomb substrates are useful for evaluating the effect of the mechanical signal-derived geometry on the transduction system of cells.

Porous surface patterns are used in a wide variety of practical applications. Honeycomb-patterned porous polymer films are good templates for preparing porous surfaces due to their simple fabrication and the arrangement of pores on the surface. Catechol groups include in adhesive protein of mussels have attracted much attention due to their highly and substrate-independent adhesive properties. In this paper, highly and substrate-independent adhesive honeycomb-patterned porous polymer films are prepared by using amphiphilic copolymer having catechol moieties. Furthermore, porous surface patterns are transferred on various organic or inorganic substrates by wet etching with using adhesive honeycomb films as templates.

Polymer micro- and nano-particles have attracted much attention because of their promise for a variety of applications. This focus review introduces an emerging method for producing nanostructured polymer particles, called self-organized precipitation (SORP), and gives an overview of controlling the internal structure of polymer particles by using various polymer blends and block-copolymer systems. The possible applications and future prospects of this technology are also discussed. Polymer Journal (2013) 45, 261-268; doi:10.1038/pj.2012.151; published online 8 August 2012

In this paper, we show the first demonstration of a substrate-independent thermal nanoimprint lithography (T-NIL) process by using a mussel-inspired amphiphilic polymer as an adhesive layer. Since the thin adhesive layer comprised of the mussel-inspired amphiphilic polymer strongly bound substrates and polymer layers, surface patterns successfully transferred onto polymer layers by T-NIL process without any exfoliation even at near the glass transition temperature of the polymer. By using this biomimetic T-NIL process, surface patterns successfully transferred even onto a poly(tetrafluoroethylene) (PTFE) substrate, which is one of the most non-adhesive materials.

Microspheric Janus particles with maghemite nanoparticles (NPs) in the hemisphere were investigated. Poly(styrene) (PS)-grafted maghemite NPs were embedded into the PS phase of a PS-poly(isoprene) (PI) Janus polymer particle prepared by a Self-organized Precipitation (SORP) method. The obtained Janus particles showed magnetic field responsive drifts and rotation in water. Potential application in electric paper pixels can be expected from the anisotropic magnetic response of the particle.

Hierarchical porous inorganic materials have attracted much attention, due to their large surface area and fast substance diffusion. We have prepared hierarchical porous films composed of Al2O3 nanoparticles (NPs) using the breath figure technique. The Al2O3 NPs were stabilized using an amphiphilic copolymer that contained catechol moieties. Porous films of polymer-stabilized Al2O3 NPs were prepared using water droplets as templates. The films were sintered to produce hierarchical porous Al2O3 films that were thermally and chemically stable.

Assembly of submicron-sized microspheres has received much attention due to its high potential for wide variety of applications. We have developed a preparation method of polymer particles by simple mixing of a poor solvent into the polymer solution followed by evaporation of a good solvent. By using this technique, silica nanoparticles and polymer composite particles were prepared. Preparation of three-dimensional assemblies of silica particles in polymer particles and composite Janus particles are shown.

A bottom-up approach to creating 3D assemblies of Au nanorings by drying aqueous dispersions of PS colloidal particles and Au NPs is shown. The evaporation of water from the dispersion allowed for the formation of hexagonally assembled colloidal crystals and nanorings composed of Au nanoparticles among the PS colloidal particles. The size of the nanorings could be controlled on a scale of tens to hundreds of nanometers. After sintering, the Au NPs formed Au nanorings. This simple approach supplies a potentially useful path to novel plasmonic materials and unique metamaterials for the visible light region.

Control of friction is one of the big issues to resolve energy problems. Unique, superior functional surfaces are formed by self-organization and self-assembly processes in nature. By mimicking such surfaces, we have the possibility to obtain friction-controlling surfaces. We have reported that honeycomb-patterned polymer films and micro lens arrays (MLAs) can be prepared by a self-organization process and simple molding methods. In this study, we prepare silver microdimple-arrays (MDAs) using MLAs as templates and electroless plating of silver and measured surface frictional properties of the resulting silver MDAs. The prepared silver MDAs have hexagonally arranged hemispherical micro pore and spike structures, completely covered with silver. The silver MDAs showed lower friction coefficients than similar flat silver films. These results suggest silver MDAs can be used as low friction surfaces.

Euler buckling forms surface microwrinkles ranging in size from sub-micrometers to tens of micrometers as a result of the modulus difference between the surface of the material and the material itself. When the buckling occurs in the limited areas smaller than the wrinkle wavelength, the shape of the buckled surface deforms into concave dimples or convex lenses. The shape of the buckled surface can be controlled by changing the modulus of poly(dimethylsiloxane). Hierarchical patterning can also be achieved by using a photomask. This surface wrinkling process provides a novel way to nano-and micropattern soft substrates, including elastomers and gels.Polymer Journal (2012) 44, 573-578; doi:10.1038/pj.2012.43; published online 4 April 2012

In this account, we review recent developments in the preparation of various functional and nanostructured polymer particles by precipitation-based methods. First, we present an overview of recent polymer particle preparation methods including methods for precipitation-based particle preparation. Next, we introduce the self-organized precipitation and its advantages. We discuss the morphological control of polymer particles based on the types of polymer materials used for particle preparation. We also introduce the preparation of organic inorganic composite particles. Finally, we discuss the future outlook of nanostructured polymer particles.

The effect of confinement on microphase-separated structures of a diblock copolymer is investigated in nanoparticles serving as a three-dimensional (3D) confinement system. We succeeded in preparing nanoparticles having various types of complex structures from hydrophobic diblock copolymers by a simple solvent evaporation method. The detailed 3D structural analysis of the nanoparticles by transmission electron microtomography (TEMT) revealed that complex structures were found only to form in the nanoparticle surface region, the thickness of which corresponded to the single-molecule length of the block copolymer in the bulk state. These results indicate that 3D confinement fundamentally affects block copolymer self-assemblies most strongly in the surface region of nanoparticles but only weakly in the central region.

We have demonstrated the simple preparation of structurally colored composite films by stacking alternating Os and PB layers. Os has a much higher refractive index than PB, which causes the strong reflection at the interface between these two materials. Strong reflection colors were observed because of the interference between the multi-layers. Active control of the reflection peaks was achieved by swelling the PB layers. From these results, we conclude that black thin layers enhance the reflection of structural colors.

We show here a simple and versatile preparation method of "suprapolymer assemblies'' including nanowires, nanorings, and nanospheres based on the phase-separated structures formed in symmetric poly(styrene-block-isoprene) (PS-b-PI) and homo-polystyrene (h-PS) blended particles. The morphological control of phase-separated structures has been performed in the blended particles by changing amounts and molecular weights of blended homopolymers. Varieties of suprapolymer assemblies were prepared from these blended particles by a simple crosslinking and elusion procedure.

In this study, metal-polymer particles with microphase-separated structures were prepared by self-organized precipitation, where a good solvent is evaporated from a solution that also contains block copolymer, Au NPs, and a poor solvent. Control of the microphase-separated structure in composite particles consisting of Au NPs and block copolymer was accomplished by changing the Au NP size, the mix ratio, and the copolymerization ratio of the block copolymer. The morphology of the inner structures was changed from a lamellar phase to a spherical phase by increasing the Au NP concentration. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1717-1722, 2011

Flexible, optically transparent, and conductive line-and-space patterns were prepared by a simple coating of gold nanoparticle (Au NP) dispersions onto both glass and flexible polymer substrates. The Au NP dispersion was injected into the gap between the two solid substrates, and then the upper substrate was straightly moved by using a hand made apparatus equipped with a stepping motor. Owing to the dewetting of the Au NP dispersion on the substrate, line-and-space patterns were spontaneously formed from the receding meniscus of the Au NP dispersion supplied from the edge of the upper substrate. After sintering, the line-and-space-patterned film showed optical transparency (more than 80%) and in-plane anisotropic conductivity (3.82 x 10(3) S.cm(-1)). (C) 2011 The Japan Society of Applied Physics

Three-dimensional (3D) assemblies of metal nanoparticles are promising materials for plasmonic materials. Metal nanoparticles have unique surface plasmon resonances, ranging from ultraviolet to visible light wavelengths, depending on their metal species, size, and shape. The arrangements and spacing of the nanoparticles also strongly affect the plasmonic properties. The microphase separation of block copolymers can create a nanoscopic periodic structure, where metal nanoparticle assemblies are arranged along the microphase separation structure. In this paper, we construct 3D Au nanopartide assemblies embedded in the microphase separation structures of confined block copolymers, in the pores of inverse opals. Polymer-stabilized Au nanoparticles were synthesized, and submicrometer poly(styrene) ;(PS) colloidal crystals were prepared using a simple coating method, After molding a PS colloidal crystal with poly(vinyl alcohol) (PVA), block copolymers and Au nanoparticles were introduced into the PVA inverse opal from solution. The inner nanostructures were analyzed by transmission electron microscopy (TEM).

Wood cell wall, composed of polysaccharides (cellulose and hemicelluloses) and an aromatic polymer (lignin), exhibits a honeycomb-like alignment. We have been making attempts to fabricate cellulose-based materials to reconstruct these wood components artificially, mimicking their formation processes. Those attempts are aiming not only at better understanding of the significance and the function of each wood component, but also at providing a novel, biomass-based polymer material with functionality. This article outlines a protocol to prepare honeycomb-patterned cellulose films with two different polymorphisms, carrying different pore sizes, as a basic framework of the artificial cell wall structure. It also illustrates the effect of the presence of hemicellulose and lignin on the physical property of the honeycomb-patterned cellulose films, when they were adsorbed onto the films. (C) 2010 Elsevier B.V. All rights reserved.

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In this paper, we show a simple biomimetic approach for fabricating thermally stable porous films with multilayered structures by mimicking beetle wings. Honeycomb-patterned porous films (honeycomb films) of poly(1,2-butadiene) (PB) were successfully prepared by casting chloroform solution of PB and amphiphilic polymer under humid conditions. After formation of layer-by-layer (LbL) film of poly(amic acid) (PAA), which is a precursor of polyimide, and poly(allylamine hydrochloride) (PAH) onto the surface of PB honeycomb films, PAA was successfully converted to polyimide by chemical imidization. After imidization, the LbL-coated honeycomb films have high thermal stability.

The preparation of size-controlled CdS nanoparticles in block copolymer micelles and formation of composite particles of CdS nanoparticles and polymers are described in this paper. Uniformly sized CdS nanoparticles with different emission wavelengths were successfully synthesized. In addition, composite Janus particles, unidirectionally stacked lamellae particles and onion particles were formed by combining CdS nanoparticles and polymer blend or block copolymer systems. This approach provides a simple route for the preparation of functional organic/inorganic composite particles. Polymer Journal (2011) 43, 301-305; doi: 10.1038/pj. 2010.137; published online 19 January 2011

Anisotropic polymer meshes, which have micrometre-scale rectangular pores, were prepared by simple stretching and photo-crosslinking of poly(1,2-butadiene) honeycomb films. First, honeycomb films with pores of uniform size were prepared by a simple self-organization process. Then, after stretching and UV photo-crosslinking, anisotropic polymer meshes were formed. These anisotropic polymer meshes had high chemical and thermal stability, and exhibited anisotropic wettability. Moreover, by using a photo-crosslinking process, the anisotropic meshes could be photo-patterned. These anisotropic polymer meshes are expected to be applicable to digital microfluidic devices, cell aligners, and other such devices.

Blue light-emitting Au nanoclusters were synthesized in a simple one-pot process via reflux of Au ions with amino-terminated poly(1,2-butadiene) in toluene. DLS results and photoemission spectra showed that Au-8 nanoclusters were successfully formed. Moreover, photo-patterned films containing Au-8 clusters were prepared by photolithography.

Japan has been operating 'KIBO' ('hope' in Japanese) as Japanese experimental module on ISS (International Space Station) to perform researches on physical, life, medical, space sciences in space. Several research racks and facilities have already been accommodated in the pressurized module of 'KIBO' and some researches have already been carried out. Japan currently has 17 ISS flight projects (including 4 candidates) in the field of physical sciences and also incubates new projects through a research support program named as 'research WG (Working Group)', where 25 research WGs are active in the field of physical sciences. Those include 1 flight candidate and 2 research WGs in the field of physical chemistry. The article introduces those to promote international collaborations.

In this report, we present a novel and simple method of fabricating robust, anisotropic, and patterned honeycomb and pincushion films by photo-cross-linking of poly(1,2-butadiene) (PB). We show that honeycomb films can be prepared by casting a solution of an amphiphilic polymer and a hydrophobic polymer under humid conditions. Thermally and chemically stable PB honeycomb films, which exhibit high water repellency, can be fabricated by irradiation of UV light. The patterning of honeycomb and pincushion films can be performed by heat treatment after UV light irradiation through a photomask. Furthermore, anisotropic honeycomb and pincushion films can be prepared by stretching.

We report a simple, novel method for obtaining structurally colored films consisting of poly(1,2-butadiene) (PB) and Os multi-layers that mimic the surface structure of jewel beetle elytra. Strong color reflection was achieved by interference of light at the interface between the multi-layers. Active control of the reflection peaks was achieved by swelling the PB layers with solvent, and photopatterning of the composite film was also performed.

We demonstrate here a creation of a novel biomimetic bi-functional surface by using dry etching of silicon with a self-organized porous polymer. The novel silicon structures with hierarchical nanospike-array structures covered with fluorocarbons were fabricated by dry etching of silicon through the porous polymer masks. The anti-reflection and superhydrophobic properties were realized due to their large surface areas and low surface energies. These masks and silicon substrates offer great advantages and are suitable for various practical applications, including high efficiency solar cells. © The Royal Society of Chemistry 2010.

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Microporous polymer films can be prepared by casting a solution of hydrophobic polymer and amphiphilic polymer on a solid substrate using condensed water droplet arrays as templates. Because of the temperature nonuniformly of the solution surface owing to thermal convections water condenses heterogeneously. The heterogeneous condensation of water droplets induces the formation of irregular size and arrangement microporous film. To evaluate the effect of gravity on microporous film formation. We have successfully prepared the test chamber for hypergravity experiments. From the hypergravity experiment, the thermal convection during solvent, evaporation was forced to be enhanced under hypergravity. As a result, the microporous structure was not observed under hypergravity. These results provided insight on water assisted microporous film formation. Furthermore, the results strongly suggested that the microgravity environment is suitable for uniform and well organized microporous film formation (C) 2010 Japan Society of Applied Physics

Block copolymer nanopaticles were prepared from the mixture solutions containing good/poor solvents by a simple evaporation process. The block copolymers formed disorder, unidirectionally stacked lamellar, and onion-like structures in nanoparticles depending on preparation temperatures. Thermal annealing induced the disorder-order phase transition and order-order phase transformation in the block copolymer nanoparticles, even though the annealing temperature is lower than the of one polymer segment. The unusual thermal behaviors suggest that the glass transition temperature of the block copolymer is decreased by the effect of nanoparticle, whose surface areas are larger than their volumes.

Nanoparticles with concentric layered structures were generated from a lamellae-forming poly(styrene-b-isoprene) diblock copolymer using controlled precipitation from a tetrahydrofuran/water mixture. Chloroform, a good solvent for both blocks, was used to swell and anneal the nanoparticles suspended in aqueous media. The three-dimensional morphologies of particles were reconstructed by transmission electron microtomography throughout the process of solvent annealing. A transition from concentric lamellae to PI cylinders in a PS matrix occurred upon annealing, presumably due to a slight selectivity of chloroform for PS. These cylindrical microdomains were further divided into PS-core PI-shell spherical structures in a PS matrix upon extended annealing, a structure that is unique among reported microphase separated morphologies of diblock copolymers.

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Au nanoparticles (NPs) and polymer composite particles with phase-separation structures were prepared based on phase separation structures. Au NPs were successfully synthesized in amphiphilic block-copolymer micelles, and then composite particles were formed by a simple solvent evaporation process from Au NPs and polymer solution. The phase separated structures (Janus and Core-shell) were controlled by changing the combination of polymers having differing hydrophobicity.

This paper reports static and dynamic control of the phase separation structures of polymer blended nanoparticles. The phase separated nanoparticles were prepared from various combinations of polymers by evaporating good solvents from the polymer blended solutions after adding poor solvents into the solutions. Transmission electron microscope observation of the nanoparticles shows that two types of phase separation structures were formed in them. One is Janus type structure and another is core-shell type structure. When the difference of the Flory-Huggins solubility parameter (delta) between two blended polymers is large, one polymer having a higher delta value encapsulated another polymer. As a result, a core-shell type structure is formed. On the other hand, when the difference of d value is small, both moieties of polymer are exposed to the poor solvent, and then, a Janus structure is formed. Moreover, when the thermoresponsive polymer was blended with a hydrophobic polymer, a Janus type or core-shell structure was formed by changing the preparation temperature. The core-shell type structure was transformed to a Janus type structure by heating the nanoparticles. This control and transformation of structures of nanoparticles can be applied to nano-sensing devices, switching devices and drug delivery systems.

Honeycomb-patterned polymer films prepared by the simple casting of a polymer solution under humid conditions were used as templates for metal microdot arrays formed on shrinkable polymer substrates by metal sputtering. After thermal shrinkage of the substrate, the periodicity of the metal microdots was reduced. in addition, microwrinkles were formed on the metal microdots. The wavelength and arrangement of the microwrinkles were changed with the metal sputtering time and the diameter of the metal microdots. A clear confinement effect was observed in the formation of the microwrinkles.

Self-organized honeycomb-patterned polymer films were prepared by using condensed water droplet arrays as templates. Porous polymer masks for dry etching were easily prepared on Si substrates by peeling off the honeycomb-patterned films. After dry etching, hexagonally-arranged micro-pores were formed on the surface of Si substrates.

Honeycomb films were prepared by using a photo-responsive amphiphilic copolymer containing photochromic spiropyran. Through the photo-responsivity of spiropyran, the molecular polarities provide solubility changes against chloroform vapor after UV irradiation. The merocyanine area formed with UV irradiation retained its honeycomb-pattern against chloroform vapor, though the spiropyran area without UV irradiation dissolved.

By photo-patterning of photochromic honeycomb films and electroless plating, patterned silver honeycomb films were prepared. A photochromic amphiphilic copolymer containing spiropyran was successfully synthesized, and used for honeycomb film preparation. After photo-patterning of the photochromic honeycomb film, the photo-patterned regions were metallized by electroless plating. After solvent vapor treatment, only the metallized honeycomb region kept its structure.

Micro droplet handling is very important for micro and nano fluidic devices and an intelligent bio interface. Micro droplet transfer via a high adhesive superhydrophobic surface has been reported in recent years. We demonstrated water droplet adhesion controllable superhydrophobic metal polymer surfaces. Moreover we achieved micro droplet transfer between superhydrophobic surfaces by using different droplet adhesion properties. Water micro droplets were transferred from a low-adhesive superhydrophobic surf ace to a midium-adhesive superhydrophobic surface via a high-adhesive superhydrophobic surface without any mass loss. After droplet transfer, water contact angle was about 150 degrees. Droplet handlings on the adhesive superhydrophobic surfaces will be expected for fluidic bin devices with energy saving.

We have already fabricated honeycomb-patterned cellulosic films with cellulose I and II polymorphisms as a basal framework in order to create an artificial woody cell wall.[1,2] The adsorption of an isolated lignin, acetic acid lignin (AL), was attempted onto the honeycomb films not only to develop materials further mimicking the cell wall but also to elucidate the mechanical effect of isolated lignin on the tensile strength of the cellulosic architecture. The tensile strengths of honeycomb-patterned cellulosic films were improved by the AL adsorption. Although the cellulosic films without lignin weakened under high moisture content conditions as compared with those under the low content conditions, the lignin-adsorbed cellulosic film maintained significant tensile strength even under the high content conditions. This result suggests that lignin contributes to reinforce the mechanical strength of cellulose framework, in particular high moisture conditions.

This paper describes the first preparation of diblock-copolymer blend particles with hierarchical inner structures. AB/AC type diblock-copolymer blend particles were successfully prepared by a simple solvent evaporation method. The inner phase separation structures can be controlled by changing the molecular weight combinations of common polymer segments. Furthermore, the one-to-one blend of two diblock-copolymers formed Janus particles with two different domains of microphase separation. Pd ions were successfully introduced into the particles with the onion-like structure. These organic-inorganic composite particles can be used as a novel class of nanomaterials applicable to photonics and electronics.

Honeycomb-patterned cellulose films were prepared, and coated with arabinogalactan, a larch hemicellulose. An application of the hemicellulose-coated, honeycomb-patterned cellulose films was proposed. First, we attempted to control the pore sizes of honeycomb-patterned bacterial cellulose (HPBC) films. HPBC films with pore sizes of 10, 15, and 20 mu m were successfully fabricated, but the one with a pore size of 5 mu m was not. Second, we evaluated the applicability of the arabinogalactan-coated, honeycomb-patterned regenerated cellulose (HPRC) films to scaffolds for hepatocyte culture. It was observed that the arabinogalactan-coated HPRC films had a unique adhesion of hepatocyte: formation of spheroid-like structure and insertion of individual globular cells each in the honeycomb pores.

Silver spike arrays with triangular sharp edges were prepared by using a self-organization process based on the condensation of water droplets and the vapor deposition process. Strongly enhanced Raman scattering of rhodamine 6G on the spike arrays were shown.

Polymer nanoparticles with phase-separation structures can be prepared by simple solvent evaporation process from block copolymer or polymer blend solution (self-organized precipitation (SORP)). In this report, core-shell organic-inorganic nanocomposite particles were prepared by combination of block copolymer stabilizing Au nanoparticles and polymer blend. Block copolymer stabilizing Au NPs were prepared by reduction of Au ion in their micelles. Nanocomposite particles of poly(methyl methacrylate) (PMMA) and block copolymer stabilizing Au NPs are successfully prepared by using the SORP method.

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Side-chain type liquid crystalline polyacetylene, which has mesogenic moieties as side chains, is one of the promising materials for practical applications in the electronics. Micropatterning of the conductive polymer is a significant issue in this field. We show a simple method to fabricate micropatterns of side-chain type liquid crystalline polyacetylene derivative. Under dry condition, stripes patterns and lattice pattern were formed based on the fingering instability and stick-slip motion of the receding meniscus. Honeycomb-patterned polymer film was obtained by casting polymer solution under humid condition. The micropatterns drastically changed by changing solution concentration and preparation conditions. (C) 2008 Elsevier B.V. All rights reserved.

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A honeycomb-patterned film is formed by casting a polymer solution of polystyrene and amphiphilic copolymer under humid condition. Amphiphilic copolymers stabilize condensed water droplets as temporal templates. Therefore, physical properties of the amphiphilic copolymer are important factors for stability of condensed water droplets and the structure of the honeycomb-patterned film. In order to verify the effect of the interfacial tension between water and chloroform Solution of the amphiphilic copolymer, which is one of the important physical properties, amphiphilic copolymers were synthesized from hydrophobic monomer and hydrophilic monomer at various copolymerization ratios. The interfacial tension decreased with increasing the copolymerization ratio of the hydrophilic comonomer. Uniformity of micropores of the honeycomb-patterned film increased with decreasing the value of the interfacial tension. Moreover, polymer frame of honeycomb-patterned film became thinner with decreasing the value of the interfacial tension. These results indicate that the structure of honeycomb-patterned film can be controlled by the interfacial tension between water and polymer solution.

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Polymer particles were prepared by evaporation of good solvent from a polymer solution containing poor solvent. By using this "Self-ORganized Precipitation (SORP)" method, one could prepare particles of poly (styrene-block-vinylpyridine) (PS-b-PVP) dispersed in water. After preparation of PS-b-PVP particles, a solution of metal salts was mixed into the particle dispersion to form complexes of metal and PVP segments. Scanning transmission electron microscopy reveals that phase-separation structures of metal-complexed block-copolymers were formed in their particles. The phase-separation structure was different depending on the concentration of PVP segments. These results indicate that metal-polymer hybrid particles can be formed by simple solvent evaporation and metallization processes.

Hexagonally packed water droplets condensed on a polymer solution are potential templates for the formation of honeycomb-patterned porous polymer films. A small number of surface-active molecules is indispensable for the stabilization of water droplets during solvent evaporation. Biocompatible surfactants; e. g., phospholipids, are required for the fabrication of biodegradable honeycomb-patterned polymer films, which can be used as novel biomedical materials, mainly in vivo. Among various kinds of phospholipids, dioleoylphosphatidylethanolamine (DOPE) has been reported to be the most suitable surfactant for the formation of honeycomb-patterned PLA films. Interfacial tension between a water droplet and the polymer solution is largely dependent on the chemical structure of the phospholipids. DOPE shows high interfacial tension, resulting in the stabilization of water droplets during solvent evaporation. Dierucoylphosphatidylcholine (DEPC) and dierucoylphosphatidylethanolamine (DEPE), both of which display high interfacial tension, were also found to be suitable biocompatible surfactants.

Micro droplet handling is very important for micro and nano fluidic devices and an intelligent bio interface. Micro droplet transfer via high adhesion superhydrophobic surfaces has been reported in recent years. We demonstrated water droplet adhesion controllable superhydrophobic metalpolymer surfaces. Moreover we achieved micro droplet transfer between superhydrophobic surfaces by using different droplet adhesion properties. Water micro droplets were transferred from a low-adhesive superhydrophobic surface to a middle-adhesive superhydrophobic surface via a high-adhesive superhydrophobic surface without any mass loss. After transferred droplet possessed high water contact angle over 150 degrees. These moving processes were performed repeatedly. Droplet handlings on the adhesion superhydrophobic surfaces will be expected for fluidic bio devises with energy saving.

Microporous films with various kinds of geometrical patterns including ellipsoids and rectangles are fabricated by using a self-organization process and shrinking. A shrinkable substrate can be used to change the shapes and sizes of honeycomb pores. The pit size can be miniaturized from several micrometers to hundreds of nanometers by repeating the shrinkage.

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We report selective metal deposition of self-organized honeycomb-patterned polymer (hp) films possessing hydrophobic surfaces by all-wet electroless plating. Nickel/phosphorus (Ni/P) coated hp films were fabricated as follows. A catalytic nucleus of electroless plating was adsorbed on hp films by immersion in a saturated ethanol solution of palladium(II) chloride (PdCl2). Homogeneous metal deposition on the hydrophobic surface of the hp film was easily carried out by all-wet process. In addition an ultrahydrophobic surface of pincushion-structured polymer (ps) films having periodic pillars which was obtained by peeling off a top layer of the hp film was metal-coated by the same all-wet process. It was found that immersion in the saturated ethanol solution of PdCl2 is suitable for catalyzation on hydrophobic surfaces for metal deposition by all-wet electroless plating. To use differences of wettability of honeycomb structures between inner and outer surfaces of porous cavities, site-selective Ni/P deposition in porous cavities was carried out by immersion in a palladium chloride acid aqueous solution after ethanol treatment. (C) 2007 Elsevier B.V. All rights reserved.

In this report, we show the preparation of honeycomb-like mesh film and microdot structures by simple ultrasonication of cross-linked honeycomb-patterned film prepared by self-organization in organic solvents. We have reported that cross-linked honeycomb-patterned films can be prepared from casting liquid type photo-crosslinkable resin by using condensed water droplet arrays formed on the solution surface as templates. In order to obtain well-arranged honeycomb-patterned film of photo-crosslinkable resin, the UV irradiation timing is optimized. After immersion of the cross-linked honeycomb-patterned film in chloroform and ultrasonication, honeycomb-like mesh was separated from the photo-crosslinked honeycomb-patterned film. The microdot structure was remained on the surface of the film. The formation mechanism of honeycomb-like mesh and microdot structure was discussed. (C) 2007 Elsevier B.V. All rights reserved.

In this report, we investigated the effect of annealing on the phase separation structures formed in the block-copolymer nanoparticles. The nanoparticles with the lamellar structures were prepared by evaporation of tetrahydrofuran (THF) from the THF/water solution of poly(styrene-b-isoprene), in which each polymer segment has almost same length. Scanning transmission electron microscope (STEM) observation of the block-copolymer nanoparticles and their cross-section image revealed that the consecutive lamellar structure was formed one-directionally in the nanoparticles. When the suspension of lamellar-structured nanoparticles was annealed at 50 degrees C for 10 h, the lamellar phase changed to the disorder structures. This transition was irreversible. This result shows the lamellar structure formed in nanoparticles is less stable than that in the planar film. (C) 2007 Elsevier B.V. All rights reserved.

We show a simple preparation procedure of particles with unique shape and inner structures of polymer blend. Submicron sized particles consisting of polyisoprene (PI) and poly(methyl methacrylate) (PMMA) were prepared by adding a poor solvent (water) into a tetrahydrofuran (THF) solution of these polymers and following evaporation of THF. The diameter and shape of particles were controlled by changing the concentration of the solution. After selective staining of PI by osmium tetraoxide, particles were observed by scanning transmission electron microscopy (STEM). The observation showed the hemispherical particles with PI core and PMMA shell were formed. After dispersion of the stained particles into THF, the hemispherical particles of the cross-linked PI core were obtained by the selective dissolution of PMMA shell. (C) 2007 Elsevier B.V. All rights reserved.

This report describes the electroless deposition of zinc oxide on pincushion-like polymer structures prepared by self-organization. By using condensed water droplet arrays as templates, a honeycomb-pattemed film was formed after evaporation of solvent and template water droplets from casting polymer solution. Well-ordered pincushion structures were prepared by peeling off the top layer of the honeycomb-pattemed film. Thin catalytic gold layer was sputtered onto the pincushion film of polystyrene and amphiphilic copolymer, and the gold-coated pincushion film was dipped in an aqueous solution containing zinc ion and reducer. The scanning electron microscopy and X-ray photoelectron spectroscopy revealed that zinc oxide layer was formed on the gold-coated pincushion film. (C) 2007 Elsevier B.V. All rights reserved.

Surface wettability is a significant factor in determining the physical and chemical properties of materials. It is known that both the chemical properties of the surface and its topography play important roles. A, honeycomb-structured polymer film can be prepared by casting a hydrophobic polymer solution under humid conditions. Here, we measured water repellency on the honeycomb- and pincushion-structured films of various kinds of hydrophobic polymers. We show that the honeycomb- and pincushion-structured films of hydrophobic polymers have high water repellent properties. Especially, the water contact angles on pincushion-structured films are over 130 degrees. From the results of these experiments, it appears that the surface structures prepared by self-organization process enhance the hydrophobicity of the surface. An easy process for creating highly water repellent surfaces is required to utilize these surfaces in industrial applications. Thus, the simple self-organization process has advantages from the standpoint of application. (c) Koninklijke Brill NV, Leiden, 2008.

We demonstrate the preparation of particles with a variety of inner structures from block-copolymers and polymer blends by using a simple solvent evaporation process. One-directionally stacked or onion-like lamellar structures were formed from symmetric block-copolymers. Asymmetric block-copolymers formed cylindrical phase in nanoparticles. "Janus''-type particles were prepared from homopolymer blends. A network structure was formed in the homopolymer blend particles containing block-copolymers, which work as compatibilizers for homopolymer blends.

Honeycomb-patterned films were prepared by using orderly arranged water droplets as templates. By using the honeycomb-patterned films as templates, Pt/Pd metal microdot arrays were formed on solid substrates. Silver layer was formed on the Pt/Pd layer by electroless deposition, and then, the microdiscs of Ag were obtained by removing the substrate.

We demonstrate here a novel pattern transferring method named "Contact Etching Lithography" onto stretched polymer films by using a solvent-swollen polydimethylsiloxane (PDMS) molds as a template. Furthermore, the transferred patterns can be miniaturized by thermal shrinking of the patterned stretched polymer film.

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We have reported that honeycomb-like porous polymer films, which were spontaneously formed in the casting of polymer solutions under humid conditions, were converted into honeycomb-like metal meshes by electroless plating. In this report, the unique optical properties of these meshes will be discussed. Silver-coated honeycomb mesh films were prepared by self organization and electroless plating methods. The incident angle dependence of their transparency, and their electrical conductivity were measured. The metallized film had limited viewing angle.

Honeycomb-patterned film was prepared by casting chloroform solution of hydrophobic polymer and dye-containing amphiphilic Copolymer under humid conditions. The confocal laser scanning microscopy image shows that amphiphilic copolymer is localized around the pores of the honeycomb-patterned film.

Particles of a poly(para-phenylenevinylene) (PPV) precursor were prepared from an aqueous solution of the polymer by simple evaporation of water from the solution, which also contained an ionic liquid as a poor solvent (self-organized precipitation (SORP) method); PPV precursor nanoparticles were successfully converted to PPV nanoparticles after annealing at 240 degrees C under reduced pressure, this simple process constituting a novel route to nanoparticles of functional polymeric materials.

Bacterial cellulose (BC)-producing bacterium, Gluconacetobacter xylinus (ATCC53582), was found to move along linear microgrooves of a stripe-patterned cellulosic scaffold. On the basis of this finding, fabrication of honeycomb-patterned BC was attempted by controlling the bacterial movement using a agarose film scaffold with honeycomb-patterned grooves (concave type). The patterned agarose film was prepared by three steps. The first was transcription of a honeycomb-patterned polycaprolactone film template with polydimethyl siloxane. When the bacteria were cultured on the scaffold under atmospheric conditions, only bacterial proliferation was observed. Honeycomb-patterned BC was obtained when cultured under a humid CO2 atmosphere. Electron diffraction and polarized microscopic observation showed that the patterned BC comprised of the well defined cellulose lot microfibrils. As another attempt to fabricate honeycomb-patterned BC, the bacteria were cultured on the patterned cellulose and agarose film with convex type of honeycomb. This culture yielded no honeycomb-patterned BC. Therefore, concave type honeycomb scaffold is more suitable to fabricate honeycomb-patterned BC. (c) 2006 Elsevier Ltd. All rights reserved.

In this paper, we investigated the effect of annealing on the phase separation structures formed in block copolymer nanoparticles. The nanoparticles with the lamellar structures were prepared by evaporation of tetrahydrofuran (THF) from the THF/water solution of poly (styrene-b-isoprene). Scanning transmission electron microscope (STEM) observation revealed that the consecutive lamellar structure was formed one-directionally in the nanoparticles. When the suspension of lamellar-structured nanoparticles was annealed at 50 degrees C for 10 h, the lamellar phase changed to a disordered structure. This transition was irreversible. This result shows the lamellar structure formed in nanoparticles is less stable than that in the planar film.

Controlling cell responses to material surfaces is important for tissue engineering. Topographical property on material surfaces can play a crucial role in directing nerve regeneration. We prepared regular stripe-patterned (groove-ridge pattern) polymer film by self-organization in order to control direction of neurite extension. Neural cells from cerebral cortex of embryonic day-14 mice were cultured on the film coated with poly-L-lysine. Here, we describe a complex and unusual contact guidance dependent on the pattern feature size. The neurites grew perpendicular to wide groove of 12.7 mu m and wide ridge of 4.3 mu m but parallel to narrow grooves (6.1 and 8.4 mu m) and narrow ridge (2.2 and 3.6 mu m). The neurites sprouted parallel to the narrow groove but uniformly on the wide groove. The emersion of neurites was suppressed and the length of neurites was longer compared with on a flat film. These results are of interest to understanding contact guidance and designing scaffold for neural network formation. (c) 2005 Elsevier B.V. All rights reserved.

We show the simple preparation of the hemispherical polymer particles. Submicron sized hemispherical polystyrene particles were prepared by adding a poor solvent (water) into a tetrahydrofran (THF) solution of polystyrene and following evaporation of THE When the concentration of the polymer solution was higher than 0.4 g/L, spherical particles were formed. On the other hand, the hemispherical nano-particles were formed in the case of the dilute solution whose concentration was lower than 0.2 g/L. Turbidity change of the polymer solution due to THF evaporation starts from the surface of the solution. The light scattering experiment suggests that the hemispherical nano-particles were formed by precipitation at the air/solution interface. (c) 2005 Elsevier B.V. All rights reserved.

This paper describes the preparation of honeycomb-patterned films from hydrophobic fluorinated copolymers. Micro-porous polymer films from fluorinated copolymers with hexagonally arranged micro-pores were prepared by casting polymer solution under humid condition. The pore size of the honeycomb-patterned film was controlled by changing casting volume. The water contact angles on the honey-comb-patterned films were measured with changing their pore sizes. The water contact angle increased up to 145 degrees, when the pore size decreased. These values fitted the theoretical calculations.

Honeycomb- and stripe-patterned regenerated cellulose films were fabricated on the basis of self-organization. The honeycomb-patterned film with mesoscopic pores was fabricated by blowing humid air to the surface of cellulose triacetate (CTA)/chloroform solution. However, the diameters of these honeycomb pores were not uniform. Such patterned film with uniform pores could be fabricated by means of the transcription method. In this method, a first template was fabricated from a mixture, chloroform solution of polycaprolactone and amphiphilic polymer by blowing humid air. A second template with honeycomb-patterned grooves was transcribed from the first template by using polydimethyl siloxane. The honeycomb-patterned regenerated cellulose film was fabricated by pressing the second template on the CTA/chloroform solution followed by drying and saponification. We also succeeded in fabrication of honeycomb-patterned bacterial cellulose film. The film was obtained by the culture of Gluconacetobacter xylinus on the agarose medium with honeycomb-patterned grooves.

In recent years, polymer nanoparticles have been investigated with great interest due to their potential applications in the fields of electronics, photonics, and biotechnology. Here, we report the spontaneous formation of polymer nanoparticles from a clear solution containing a nonvolatile poor solvent by slow evaporation of a volatile good solvent. During evaporation of the good solvent, the solution gradually turns turbid. After evaporation, polymer nanoparticles of homogeneous shape and size are dispersed in the poor solvent. Homogeneous nucleation and successive growth of polymer particles takes place during the dynamic nonequilibrium process of solvent evaporation. The size of the particles, ranging from tens of nanometers to micrometer scale, depends on both polymer concentration and the solvent mixing ratio. Because of the physical generality of the particle formation mechanism, this procedure is applicable to a wide variety of polymers with suitable combinations of solvents. Here, we also show unique features, surface structures and surface properties of polymer nanoparticles prepared by this method. (C) 2005 American Institute of Physics.

Honeycomb and stripe patterned films were prepared from cellulose triacetate (CTA)/chloroform solution, as a result of the self-organization of the polymer during evaporation of the solvent. The honeycomb patterned CTA films were prepared by two methods, a direct pattern formation method and a transcription method. The latter method gave a well-organized microporous honeycomb pattern. Both types of patterned CTA films were saponified to yield the corresponding patterned cellulose films. (c) 2005 Elsevier Ltd. All rights reserved.

Block-copolymer nano-particles with lamellar phase-separation structures (see figure) have been prepared by a slow-precipitation process. Regular-sized polymer nanoparticles are formed after evaporation of a good solvent from a polymer solution containing a non-volatile poor solvent and a volatile good solvent.

Regular polymer patterns are formed from casting a dilute polymer solution on a solid substrate. Dissipative structures, e.g., convection patterns, fingering instabilities, and so on, are formed in the evaporation process of casting polymer films. Controlled production and manufacturing of patterned polymer films can be achieved when the evaporating solution edge, especially the meniscus region on the casting substrate, is formed under controlled casting conditions. In this report, we describe a computer-controlled apparatus which has two precisely manipulated sliding glass plates. A narrow, thin liquid film of polymer solution with a receding meniscus is continuously supplied from a small gap between two glass plates (one sliding and the other stationary), and a patterned polymer film is subsequently formed on the stationary substrate from the evaporating solution edge. Several types of polymer patterns from various polymers are reproducibly prepared by changing preparation conditions such as sliding speed and polymer concentration.

Microporous polymer films are attractive materials with potential application in the fields of electronics, photonics, and biotechnology. Chemical and thermal stabilities of the microporous polymer films are required for their materials application. Besides preparation by conventional photolithography, we have reported that honeycomb-patterned porous polymer films are prepared by a method utilizing the condensation of small water droplets on solutions of amphiphilic copolymers. Here, we show preparation of honeycomb-patterned microporous films of a thermally and chemically stable material, polyimide. A water-template-assisted honeycomb structure was formed from a polyion complex of polyamic acids and dialkylammonium salt. The pore size of films was controlled by the casting volume of polymer solution. The patterned polyion complex film converted into polyimide by simple chemical treatment, keeping the porous structure. Self-supporting microporous polyimide films are fabricated. The honeycomb-structured film has high thermal and chemical stability like that of conventional cast films of polyimides.

Dissipative structures formed in the casting polymer solutions are utilized for micro- and nano-patterning of polymer materials. We have found that the typical dissipative structures were formed in the casting process of polymer solutions on solid surfaces. Dynamic regular structures formed in casting polymer solutions are fixed as regular patterns, stripes, and lattices, etc., of polymer materials. We have also found regular pattern formation in casting solutions of nanoparticles.

The honeycomb patterned titania films with submicron pores were prepared by a Sol-gel reaction. Self-organized 2D arrays of water droplets were formed on surfaces of reaction solution as a template. Polystyrene particles were embedded into the micropores of the honeycomb films by casting dispersion of the particles. The arrangement of aggregated particles was controlled by changing pore sizes.

When a droplet of a dilute solution of a polymer is allowed to evaporate on a horizontal substrate, the polymer is deposited on the substrate as a regular 2 dimensional pattern of micrometer-sized polymer droplets or lines. It was found that the mechanism of the pattern formation involves a Benard convection in the polymer solution and a regularly spaced fingering instability at the contact line of the solution with the substrate. By using liquid crystalline polymers, a novel hierarchic pattern can be observed.