Research articles

Using a facile method, a gelatin hydrogel with anisotropic gel properties was prepared on a substrate via hydrogelation to induce self-assembly. Three kinds of surface properties (structural control factors) of the template induce the formation of an anisotropic gelatin network by self-assembly. The swelling behavior and mechanical properties of the anisotropic and isotropic gelatin hydrogels are different. When the hydrogel is compressed in a direction perpendicular to the tube-like gelatin network, the inner space of the network is compressed.

This work studied the crosslinking of PLA/star-shaped polycaprolactone to enhance the toughness and resistance to thermal deformation of PLA. The tensile and thermal properties of the blend and crosslinked films were investigated. The simple test of resistance to thermal deformation by immersing in hot water was done. The crosslinked film shows resistance to deforming in hot water (80 °C, above its T_g).

Polytetrafluoroethylene (PTFE) has a weak boundary layer (WBL) on the surface. A cross-section of PTFE was observed using a scanning electron microscope for investigating the difference in morphology between WBL and bulk layer. Large voids of 0.5–2.0 µm in diameter were observed on the surface side of PTFE but not on the bulk side. These voids existed up to approximately 5 µm from the outermost surface of the PTFE. This result indicated that the thickness of WBL of PTFE was in the order of single µm.

An optically active acylhydrazine-functionalized biphenyl (AHB) carrying L-alanine-derived oligoamide side chains supramolecularly coassembled with the corresponding achiral AHB to form a one-dimensional helical nanofiber, in which intermolecular hydrogen bonding between the chiral/achiral oligoamide pendant units resulted in modest chiral amplification (the sergeants-and-soldiers effect). The chiral/achiral AHB-based covalent copolymers folded into a preferred-handed helical structure with amplification of the helical sense excess driven by intramolecular hydrogen bonds and further polymerized into a higher molar mass supramolecular helical polymer stabilized by end-to-end intermolecular hydrogen bonding.

Composites of fluoropolymer (FKM) and nano-carbon fillers have been considered as sealing materials for hydrogen fuel storage. We here characterize, structurally and dynamically, FKM chains adsorbed on single-walled carbon nanotubes (SWCNTs) and carbon black (CB), which were prepared by a solvent leaching method.

For n-type organic semiconductors, low thermoelectric conversion properties are an issue that needs to be resolved, moreover current manufacturing methods are not compatible with printing technology. In this communication, we report the systematic preparation of carbon nanotube (CNT) sheets containing dopant polymers using a drop-casting method that enhances thermoelectric performance. The inclusion of 1,2-diphenylhydrazine as a secondary dopant significantly improved the ZT value of poly(N-vinyl-2-pyrrolidone)-poly(vinyl alcohol) graft copolymer/CNT, from 5.26 × 10⁻³ for the undoped system to 1.34 × 10⁻². The developed approach, which is expected to provide on-demand manufacturing through printed electronics technologies.

A fluorescent microarray comprising polythiophene-based chemosensors functionalized with pyridinium boronic acid has been developed for the detection of the components of sake such as glucose and pyruvate. The sensor microarray was fabricated on a glass chip for on-site detection utilizing imaging analysis and pattern recognition. The selected four nondiluted sake samples were discriminated by the cross-reactive response pattern. Moreover, the facile chemosensor array realized the prediction of unknown concentrations of glucose and pyruvate in the diluted sake, which indicated its usability for drink analysis.

A novel superabsorbent polymer crosslinked with diacylhydrazine DC-SAP was prepared. A very-high water uptake (ca. 80,000%) was observed in DC-SAP at a crosslinking ratio of 1%. The swollen gel was instantly (<5 s) solubilized by treatment with a small amount of sodium hypochlorite solution. A commercially available bleacher could also be used for the solubilization of DC-SAP. Despite the high degradability of DC-SAP, it exhibited high chemical and thermal stability. The decomposition product is composed of pure poly(sodium acrylate), which is extremely safe substance.

A novel thermoresponsive diblock copolymer of methyl poly (ethylene glycol)-b-poly (O-benzyl-L-threonine) was synthesized. The copolymer solutions exhibited gel-to-sol UCST transition behavior with temperature. The gel-to-sol transition was due to the disassembly of the initial β-sheet layered nanoassemblies that induced the transformation of self-organized morphology from nanosized fibrils to spherical aggregates.

The microwave heating technique has been widely used in various organic and inorganic syntheses, and it has been reported that this technique provides the desired compounds quickly and easily. In this work, we applied microwave heating to synthesize redox-active organic nanoparticles consisting of hyperbranched viologen units. By the precise temperature control afforded by use of microwave irradiation, we succeeded in controlling the growth and termination reactions kinetically and preparing viologen nanoparticles in one-pot. We also demonstrated that the size of the nanoparticles can be controlled by varying the temperature program.

A preparation of polyacrylate-based vitrimer-like elastomers with dynamic bond-exchangeable cross-links is demonstrated. The component polymer is a poly(ethyl acrylate)-based copolymer bearing pyridine groups randomly, which was cross-linked by a quaternization reaction of pyridine groups with dibromo cross-linkers (dibromo hexane). The bond exchange is induced via trans-N-alkylation of quaternized pyridines at high temperatures, which is revealed by temperature-ramp FT-IR, elongational creep, and stress-relaxation tests. Some useful functions of the present material, such as reprocessability, thermal and chemical recyclability, are provided due to the bond exchange nature.

A reduction-responsive oligonucleotide was successfully constructed by post-modification of an oligonucleotide with a diazo compound bearing a 4-nitrobenzyl group as a reduction-responsive cleavable moiety. High-performance liquid chromatography and mass spectrometry were used to reveal the introduction of the 4-nitrobenzyl group to the 5′-phosphate group of the oligonucleotide, and the subsequent reduction-triggered recovery of the original oligonucleotide. The protocol used for the preparation of this reduction-responsive oligonucleotide is simple and it will have various applications in the fields of chemical and synthetic biology.