Series of Si-containing, especially polyhedral oligomeric silsesquioxane (POSS)-containing fluorinated block copolymers (BCPs), poly(styryl polyhedral oligomeric silsesquioxane)-block-poly(hepatafluorobutyl methacrylate) (PStPOSS-b-PHFBMA) were synthesized via living polymerizations. The flory-huggins parameter (χ, at 150 ºC) of PStPOSS-b-PHFBMA BCP was 0.060. Highly ordered hexagonal domain with 13.2 nm d-spacing was observed by small-angle X-ray scattering (SAXS) after 10 h 160 ºC annealing, exhibiting rough line patterns in scanning electron microscope (SEM). SiO_1.5 residue (13.7 wt%) still remained after 700 ºC sintering in thermal gravimetric analysis (TGA).

A series of fluorinated block copolymers (BCPs), with one block composed of random vinyl copolymers were synthesized by reversible addition fragmentation chain-transfer (RAFT) polymerization. Despite of the hugely different properties of the two monomers in the random copolymer block, highly ordered lamellar structure with sub-10 nm resolution was observed by SAXS after 160 ºC annealing for 24 h. Each micro-domain consisted of two uniformly distributed monomers, with a low T_g down to 24 ºC.

Polyhydroxystyrene (PHS)-containing block copolymers (BCPs) were synthesized via reversible addition-fragmentation chain-transfer (RAFT) polymerization, and subsequent hydrolysis. Self-assembly domain size of poly (pentadecafluorooctyl methacrylate)-block-polyhydroxystyrene (PPDFMA-b-PHS) were measured by small-angle X-ray scattering (SAXS), revealing highly ordered nanostructure. The effective Flory-Huggins parameter χ (150 ºC) is 0.268. The resulted PPDFMA-b-PHS then reacted with metal ion or metallocene compounds. BCPs chemically bonded with metal ion were obtained.

Functional dyes are one of the most attractive materials because of their potential use in microenvironment probes, bioapplications, and optoelectronic devices. The modification of chemical structures of the functional dyes due to external stimuli such as heat and photo-irradiation affects the absorption and emission behavior of the dyes. Among them, solvatochromic molecules are attracting great interest because they are used as molecular sensors and indicators. Herein, we investigated chemiluminescence using betaine 30 and dansyl acid ethyl ester (DNSE) as solvatochromic molecules. We demonstrated chemiluminescent reactions using a mixture of betaine 30 or DNSE as the functional dye and bis(2,4,6-trichlorophenyl) oxalate as a precursor to introduce a high-energy moiety under chemiluminescence conditions in several solvents. Although betaine 30 did not exhibit fluorescence except with toluene, DNSE showed different emission colors depending on the solvent polarity, which indicated that chemiluminescence depends on the environment.

Ternary polymer solar cells based on a polymer PTzBT have attracted attention because its power conversion efficiency (PCE) and thermal stability have been greatly improved by adding a small amount of an oligomer ITIC. However, the charge accumulation states of the PTzBT ternary polymer solar cells have not yet been completely clarified. Here, we report electron spin resonance (ESR) spectroscopy of layered samples of ZnO/(blend or pristine film) using PTzBT, ITIC, and a fullerene derivative PC₆₁BM to investigate the charge accumulation states of the PTzBT ternary solar cells at a molecular level. We have observed monotonic increases in the ESR intensity of the ZnO/(blend or pristine film) samples under simulated solar irradiation, where the increases in the ESR intensity of the PC₆₁BM with ITIC component are smaller than those without ITIC component. The present results would be useful to develop further highly efficient and durable polymer solar cells.

Biomimetics is attracting more and more attention as a powerful clue to cutting-edge breakthroughs in a lot of areas. Of course, it is so powerful not only for material science but also for the areas of social infrastructure such as transportation. I would like to review an example of Biomimetics in transportation, which is called as ant colony optimization (ACO), thoroughly studied in the area of mathematical optimization.

A technique for antibacterial functions is always required in such as medical treatment or food manufacturing. Sharkskin, wings of cicadas and dragonflies have antibacterial functions on their surfaces. It is attractive for human technologies to mimic their microstructural surfaces. In this study, we cultured biofilms on micro-pillar surfaces which was inspired by living organism, and evaluated the antibacterial effect. Growth of biofilms depended on the pitch and diameter of pillar arrays. Formations of the biofilm were suppressed when the pitch and diameter of the pillars were comparable to the size of the bacteria. This suppression seems to be caused by the instability of bacteria sticking on the pillar-array scaffold.

In this paper, snail's crawling motion was precisely observed and measured to understand the mechanism of its special locomotion. The locomotion has been focused on not only biological researchers but also engineers. Snails can crawl on rough surfaces with obstacles, and also can climb up even on vertical walls. These features are highly useful for applications in the field of soft robotics. We prepared an experimental setup for direct observation of the locomotion. A snail was put on a soft gel substrate, and the deformation of the substrate was measured by tracking marker particles dispersed under the surface of the substrate. At the same time, deformation of the snail’s sole was also obtained by tracing the marker particles which was embedded in the snail as fluorescent tattoo. It is essential to obtain these data at the same time to verify the reported locomotion theory. A similar observation was performed with a soft magnetic crawling robot, and we compared these data, which would be helpful to design bio-mimic soft robots like snails.

We used double-network-gel (DN-gel) to develop a new magnetic gel. Agar and Poly-acrylamide gels were selected to prepare Agar/PAAm DN-gel. We dispersed magnetic particles in this gel to fabricate a soft actuator or soft robot. Our modified DN-gel, Agar/PAAm, was suitable for this purpose. During the preparation, we employed thermal initiator instead of UV-initiator, which is popular for DN-gel, for crosslinking. The material contains magnetic particles so that it is difficult to use UV-light. The particles prevent from transmit the light. In this process, we employed thermal initiator so that UV-light is unnecessary. We also propose a micro patterning system of magnetic properties using laser scanning. CO₂ laser was employed for local heating, which can make reversible transformation of gel-liquid states. Finally, we demonstrated a simple strip soft actuator using the proposed method with DN-gel.

We propose a new method to fabricate complicated 3-dimensional glass microchannels. We employed mycelium for this purpose. Mycelium possesses a complicated, fine and three-dimensional network structure. We cultivated mycelium in silica compounds, and subsequently silica compounds were heated to be sintered. During this heating process, all the mycelium was burned off and remained a fine network channel structure in a transparent glass chip. We also tried to control of the growth of this mycelium. The growth could be changed by growth conditions. In this work, we used cyclic mechanical stimuli for this purpose. We set cyclic tensile strain to the sample under growing mycelium. This cyclic strain caused anisotropic growth of the mycelium in some condition.

This study targets development of a biomimetic technique for mitigating endoscope surface antifouling. We specifically examined a snail's shuck, which has convexo-concave microstructures, to achieve an antifouling function. Unfortunately, fabricating microstructures on lens surfaces entails large costs because of technical difficulties. As one alternative method, we fabricated microstructures on films with different PMMA concentrations and examined their surface profiles using atmospheric pressure low-temperature plasma. Convex structures on a low (67.4 wt%) PMMA concentration film have a rounded tip at high RF power. When RF power is low, however, structures fabricated on a 67.4 wt% PMMA film surface were more incisive and orderly than those on a 84.4 wt% PMMA film. Microstructures with 200-nm pitch, like a snail's shuck, were fabricated on a 67.4 wt% PMMA film when irradiating plasma at 52 W for 40 s.

Water-repellent surfaces that mimic various water-repellent surfaces of living things have been developed using photolithography technology. The water-repellency of water striders in particular has gotten a lot of attention. Micro-hairs on their legs are tilted and curved at the tip. These curving micro-hairs contribute to water-repellency properties and various reports have considered the property origins. However, the water-repellency function produced by the curved micro-hairs has not been compared with the dynamic situation (when water striders are rowing their legs), that is when there is a directly measured leg-rowing force. Therefore here, first we discussed water-repellent properties using the relationship between Laplace pressure and water pressure caused by rowing of the insect legs. In order to obtain the Laplace pressure when affected by the curved micro-hairs, a water-repellency model was proposed. To construct this new model, we measured the morphological information of micro-hairs on the tip of the middle leg (tarsus and pretarsus) and fit the curved properties of the micro-hairs to a log function. Then, the water-repellency model was constructed with the fitting curve. As a result, we derived the maximum value of Laplace pressure ΔP as 3.4 kPa. This maximum value was sufficiently larger than the water pressure (546 Pa) caused by the rowing motion of the water strider’s middle leg. Thus, we concluded that the water-repellent function due to the curved micro-hairs worked when the water strider was rowing its legs.

Biomimetics (or biomimicry) is a field of technologies based on imitating various functions and properties of organisms. Waterproof products, which are inspired by lotus leaves with super-water-repellent fine structures, are a well-known example of biomimetics. The present study examined the surface structure of snail shells, which exhibit oil repellency (oleophobic property). Snail shells have nanoporous structures with nanoholes on the scale of 200–400 nm. When water enters these nanoholes, the surface is covered by thin water films. The oil can be repelled by the water film. These structures are known as superhydrophilic nanostructures. An earlier report discussed our efforts to create such nanostructures using a nanoimprinting method and assessed the feasibility of application to the inner walls of biliary stents. This involves a labor-consuming two-stage process involving creating nanostructures on a film surface, then rolling the film into a tube. In addition, the nanoimprinting mold made via electron beam lithography is costly and unsuitable for mass production.

To overcome these issues, we sought to develop elemental technologies for providing antifouling properties to biliary stents, which are made of polyethylenes (PEs), by forming nanostructures directly on the inner surface, using atmospheric pressure low-temperature plasma. We formed nanostructures on the inner walls of PE tubes of varying diameters under varying plasma conditions. We then examined the resulting structures and effects of the antifouling properties thus imparted.

Biomimetic functional surfaces have been attracted industrial fields. The surface of a lotus leaf is a popular example of this bio-mimic surface which realize super-hydrophobicity. The key of this functional surface is a nano-patterned surface. Especially, double-roughness structure, which means rough and fine patterns on the same surface, is important. To fabricate biomimetic surfaces, nano imprint lithography (NIL) is an effective tool. NIL a low-cost lithographic method with simple thermal pressing process. Conventional NIL can form precise structures with high-resolution. We have proposed and developed some new fabrication methods based on NIL; multilayer imprinting (MLI) and in-plain compression imprinting (IPI). MLI starts with a multilayered sheet material for imprinting and results a more complex structure on the interface of the layers. IPI adds in-plane compression to NIL process to obtain structures with higher aspect ratio. There is difference between conventional NIL and these new processes. For the conventional NIL, obtained surface pattern is determined by the mold pattern. On the other hand, we could not know the interface pattern obtained by MLI or the pattern after IPI. We employed finite element analysis in this work. We used the generalized Maxwell model for the finite element analysis of our newly developed NIL. The simulation system could be a design tool for our new processes.

A sterically crowded triangular molecule (3PhA) was synthesized with three terminal triphenylamine (TPA) wings connected to the central ring structure via a diethylphenyl group. In contrast to the tendency of conventional triangular molecules to assemble into one-dimensional fibrous structures, the nonplanar distorted 3PhA formed micrometer-sized petal-like aggregates. When excited with ultraviolet (UV, 340-360 nm) and green (510 nm) light, 3PhA in organic solutions exhibited two fluorescence bands maximized at ~380-400 and ≥650 nm, respectively. The fluorescence properties did not change significantly even after the formation of flat petal-like structures. These experimental results are likely due to the distorted molecular structure of sterically crowded 3PhA, which can cause suppression of intramolecular rotation and weakening of intermolecular interactions.