A structural unit consisting of various groups of heteroatoms is defined an “element-block”. By employing new element-blocks and achieving hierarchical interface control in order to yield the desired functions, the creation of new materials that share, at a high level, various properties not achievable with conventional organic polymeric materials as well as forming properties of molding processability and flexible designability that inorganic materials lack can be expected. In this review, the recent works on the superior organic-inorganic hybrids composed of polyhedral oligomeric silsesquioxane (POSS) are introduced. By using POSS as the “element-block” for constructing functional hybrids simply by mixing into organic components, the series of “designable hybrids” can be prepared. The concept and unique characteristic are demonstrated in this manuscript.

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Self-assembling peptides have attracted much attention as nano- and bio-materials because they have promising properties such as flexible molecular design and biocompatibility. We have developed self-assembling peptides that can form various nanostructures including fibers in aqueous media, and applied them to nano/biomaterials. Functionalization of self-assembling peptides and their assembled-nanostructures was successfully achieved by chemical modification methods and molecular recognition of anchor molecules for assembled nanostructures. In particular, specific anchor peptides for assembled nanostructures enabled arranging proteins along nanofibers to yield unique structures of nanofibers. Furthermore, calcium ion-responsive hydrogel materials were constructed by chemical modification of a self-assembling peptide. These hydrogel materials allowed culturing various cells by promoting cell adhesion and differentiation. We report that our original self-assembling peptides functionalized by combination of chemical modification and molecular recognition are useful to develop highly functional nano- and bio-materials.

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There has been a great deal of interest in phosphorus containing polymers, which are synthesized as mimics of biosubstances, such as phospholipids, apatites, nucleic acids, etc. Especially, polyphosphoesters have attracted much attention in the biomedical field because they can be degraded through hydrolysis and possibly through enzymatic digestion of phosphate linkages under physiological conditions. Newly found aspects of polyphosphoesters are summarized in this review which is covering well-defined synthesis, stimuli responsive properties and applications for bone treatment. Using organocatalysts for ring-opening polymerization of five-membered cyclic phosphoesters, the molecular weight of polyphosphoesters could be controlled and coincided with the theoretical value with narrow molecular weight distribution. Some polyphosphoesters bearing simple alkyl groups show thermoresponsivity in aqueous media. This polymer solution forms a lower critical solution temperature (LCST) type coacervate. Phosphodiester polymers display high affinity for the calcium phosphate mineral which is the main inorganic component of bone. Furthermore, new composite materials for bone treatment have been proposed.

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Porous glass with 1–3 nm pore size was prepared. A trithiocarbonates-type chain-transfer agent was introduced onto the surface of the porous glass. Poly(N-isopropylacrylamide) (PNIPAM) was grafted onto the surface of the porous glass using combination of grafting-from and reversible addition-fragmentation chain transfer (RAFT) controlled radical polymerization techniques. PNIPAM shows a lower critical solution temperature (LCST ≈ 32°C) in water. Below this LCST, the pore valve was closed, because the PNIPAM grafted chains expand due to hydration. Above the LCST the pore valve opened, because the PNIPAM graft chains shrunk due to dehydration. Although low molecular weight compounds can permeate through PNIPAM-grafted porous glass above the LCST in water, the compounds cannot permeate through the porous glass below the LCST. PNIPAM-grafted porous glass can control on-off of permeation by changing temperature.

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Phenolic polymer (Poly(4-HB-co-PFA)) was prepared by addition-condensation of 4-hydroxybenzaldehyde (4-HB) which has an aldehyde and a hydroxyl group in the para position, and paraformaldehyde. Poly(4-HB-co-PFA) was dissolved in sodium hydroxide aqueous solution and reduction of silver ions was carried out in the solution under mild conditions. As a result of this reaction, it was found that silver ions were reduced to nano-sized silver particles and hybrid material (Ag/Poly(4-HB-co-PFA)) was obtained. Silver particles were coated by Poly(4-HB-co-PFA) and dispersed in the hybrid material. It was also found that the particle size of silver varies depending on the reaction conditions.

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We investigated the effect of the hydrophilicity of a crosslinker on the thermoresponsive swelling properties of poly(N-isopropylacrylamide) (PNIPAAm) gels. The gels were prepared with a variety of feed concentration of a crosslinker, poly(ethylene glycol) diacrylate (PEGDA) having a different number of ethylene glycol (EG) units. The swelling curves of the obtained gels indicate a strong relation of swelling behavior with the number of EG units in the network. The swelling degree at 10°C decreased with lower number of EG units, indicating that the crosslinking density of the gels increased. Moreover, the swelling degree at 40°C and the shrinking temperature showed almost the same value below 30% of EG content and increased linearly above this threshold value. This indicates that the hydrophilicity of the crosslinker has an effect even in the shrunken state of PNIPAAm gels.

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We have already reported that fluorescent amorphous molecular materials based on diarylaminobenzaldehyde, BMABA, BMAAP, and BFABA, exhibited solvatochromic effects, that is, their fluorescence spectra in solution altered depending upon the kind of solvent, shifting to longer wavelength with the increase in polarity of the solvent. In the present study, we have found that fluorescent colors of spin-coated films of these materials altered reversibly by exposure to solvent vapors depending on the kind of vapors; their fluorescence spectra shifted to longer wavelength with the increase in polarity of the corresponding solvent. The present vapochromic fluorescence was suggested to be due to penetration of the vapor molecules into the sample films.

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One of the filamentous viruses, M13 bacteriophage (phage), has attracted growing interest as a functional biopolymer assembly due to its liquid crystalline properties and designable functionalities based on genetic engineering and organic synthetic approaches. Recent studies revealed that phage could be utilized as superior building blocks for functional soft materials. By controlling the assembled states of phages by external stimuli, the potential applications of phage-based soft materials can be broadened. Herein, phages were chemically modified with azobenzene derivatives through an amidation reaction and the liquid crystalline properties of the azobenzene-modified phages were analyzed by polarized optical microscopy. It was revealed that 1600 molecules of the azobenzene derivatives were conjugated to a single phage. The liquid crystalline structure of the azobenzene-modified phage changed in response to ultraviolet light. Our findings will contribute to the construction of stimuli-responsive smart soft materials.

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Bisphenol A (BA) was reacted with a vinyl ether containing glycidyl group [cyclohexane dimethanol vinyl glycidyl ether (CHDMVG)] to produce bisphenol A-type epoxy resins containing acid-degradable acetal linkages (BA-CHDMVG). BA-CHDMVG was added to the conventional bisphenol A-type epoxy resins (jER828 and jER1001) and the mixture of these epoxy resins was cured to give epoxy resin boards as a candidate of matrix resins for chemically recyclable CFRP. The obtained epoxy resin boards had higher Charpy impact strength, and hence higher toughness than cresol novolak-type acetal linkage-containing epoxy resin boards (CN-CHDMVG and CN-VBGE). The (BA-CHDMVG)₄₀-(jER1001)₆₀ epoxy resin board underwent smooth breakdown with the treatment of hydrochloric acid in a tetrahydrofuran/water (9/1 v/v) mixed solvent for 24 h at room temperature. With the same acid treatment in water, on the other hand, no change occurred in the appearance of epoxy resin boards. These results indicate that the obtained epoxy resin boards are stable against acid in the normal living environment like acid rain.

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Living cationic cyclopolymerization of 1,2-bis(2-vinyloxyethoxy)-benzene (1) was investigated with the CH₃CH(OiBu)OCOCH₃/Et_1.5AlCl_1.5/CH₃COOEt initiating system in toluene at 0°C. All the reactions proceeded quantitatively to give gel-free, soluble polymers in organic solvents. The number-average molecular weight (M_n) of the polymers increased in direct proportion to monomer conversion and further increased on addition of a fresh monomer feed to the almost completely polymerized reaction mixture, indicating that living cyclopolymerization of 1 occurred. The contents of unreacted vinyl groups in the produced soluble polymers were less than ~5 mol%, and therefore, the degrees of cyclization of the polymers were determined to be over ~95%. Preparation of high-molecular-weight cyclopoly(1) was achieved by sequential monomer addition to the living polymerization system and linking reaction of living cyclopoly(1) leading to star-shaped polymers. Glass transition temperature (T_g) of linear cyclopoly(1) (M_n = 19,000) was 106°C and T_g of star-shaped cyclopoly(1) (M_n = 96,100) was 112°C, and thermal decomposition temperatures (T_ds) of these cyclopoly(1) were over 370°C, indicating their high thermal stability.

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For the promotion of material recycling, blending virgin and recycled plastic is set to be the most valuable method. However, there are few investigations that study the blending ratio dependence of the inner structure of injection molded articles and the influence on the mechanical properties. Also, there is no investigation of the difference in these properties between the entrance zone (the fastest shear rate region) and end zone (the slowest shear rate region). At this time, we investigated the inner structures and mechanical properties of entrance zone and end zone of injection molded articles of blends of virgin and recycled plastics. As result, we found that blending with recycled plastic changes the inner structure on the mesoscale substantially. We also found that the change indicates that the virgin plastic and recycled plastic do not mix very much. Additionally, the mechanical properties between entrance zone and end zone were very different at the most frequently used blending ratio, virgin:recycle = 30:70.

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Phase separation of mixtures composed of a poly(ethyl acrylate), chemically labeled with Rhodamine-B [PEAR] dissolved in a methyl methacrylate [MMA] monomer, was induced by using a computer-irradiation (CAI) method. This CAI method enables us to control phase separation under temporal and spatial restrictions on the micrometer scale. By irradiation using light stripe patterns with three periods 108, 180 and 360 micrometers, we examined the possibility of anisotropic phase separation and also clarified the experimental conditions to obtain polymer films with uni-directional bi-continuous morphology. Effects of the three factors, photo-initiator concentration, molecular weight of the guest polymer PEAR and the cross-linker concentration, on the resulting morphology were examined to establish the relation between the light patterns and the resulting morphology under these particular irradiation conditions.

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