Reviews & Analysis

Synthesis and thermal properties of poly(oligomethylene-cyclopentylene)s and poly(oligomethylene-cyclohexylene)s with regulated regio- and stereochemistry are described. Pd complexes with diimine ligands promote controlled isomerization polymerization of 4-alkylcyclopentenes and alkenylcyclohexanes to afford poly(oligomethylene-1,3-cyclopentylene)s with trans structure and poly(oligomethylene-1,4-cyclohexylene)s with trans or cis structure, respectively. Poly(ethylene-1,2-cyclopentylene) with cis and trans-stereochemistry can be obtained by Fe- and Co-catalyzed cyclopolymerization of 1,6-heptadiene, respectively. The thermal properties of the poly(oligomethylene-cyclopentylene)s and poly(oligomethylene-cyclohexylene)s are compared to those of previously reported polymers with different regio- or stereochemistry.

In this focus review, our recent progress on hybrid polymers and supramolecules utilizing silicon and arsenic is overviewed. Novel materials design based on polyhedral oligomeric silsesquioxane (POSS) has been realized by focusing on the symmetry. Practical synthetic methods have opened new avenue to experimental studies on organoarsenic compounds.

This review focuses on the recent developments on the photo-induced liquefaction and softening of azobenzene-based materials. The trans–cis photoisomerization of azobenzene units incorporated in molecular materials, polymers, and gels induces a variety of state changes such as solid–liquid, gel–sol, and glass–rubber transitions of those materials isothermally. Several novel applications such as reusable and environmentally friendly photoresists, reworkable adhesives, and self-healing materials can be expected using the photochemical liquefaction and softening.

In this focus review, our recent investigations into the deformation and fracture processes of crystalline polymers using coarse-grained molecular dynamics simulations are described. The lamellar structure of polyethylene, a fundamental structural feature of this polymer, is successfully reproduced. Then, a stress– strain curve that exhibited good consistency with that observed experimentally is obtained. Molecular simulations are a powerful tool for elucidating the mechanisms of the deformation and fracture processes of crystalline polymers at the molecular level and this review will contribute to the development of this field of research.

The true chiroptical measurements of optically anisotropic samples cannot be generally achieved with modern chiroptical spectrophotometers such as circular dichroism and circularly polarized luminescence based on polarization modulation techniques because of the coupling effect of the nonideal optics and the electronics with macroscopic anisotropies. Artifact signals related to the nonchiral phenomena are often much stronger than the chiroptical signals. Universal chiroptical spectrophotometer (UCS) and comprehensive chiroptical spectrophotometer (CCS) integrated into the Stokes–Mueller matrix analysis for optically anisotropic samples can be applicable for accurate chiroptical measurements for samples with macroscopic anisotropies.

The inclusion of electrically insulating aliphatic spacers between π-conjugated segments of semiconducting polymers represents an emerging and versatile tool to control material properties. Here we review this strategy and highlight recent reports demonstrating the control over chain self-assembly, the tunability of viscosity and elasticity, and the ability to provide insights into inter- and intra-charge transport processes—without detrimental effects on the polymer semiconducting ability. While still at an early stage, this approach gives promise towards engineering optoelectronic performance, melt-processed organic electronics, and applications toward stretchable wearable semiconducting devices.

Open-shell organic semiconductors are poised to enable new functions and applications ranging from electronics and optoelectronics to magneto-electronics. Here, we review strategies toward molecular magnets or spin–polarized magnetic organic semiconductors that encompasses incorporation of stable radical groups directly into the backbone of organic semiconductors or preparation of highly conjugated ladder-type molecules based on open–shell Kekulé–type structures to enable efficient spin delocalization/spin-transfer along the conjugation length. We briefly survey the history of this field, summarize recent developments, and set an outlook for the future.

Recent developments for nanowires fabricated from self-assembled π-conjugated polymers are reviewed. Particular attention is paid to advances in techniques for scalable production of highly ordered nanowires as well as their deposition and alignment in thin films and composites. The benefits of using π-conjugated polymer nanowires, rather than thin films, in electronic devices is examined. Devices investigated include organic field-effect transistors (OFETs), chemical sensors, and thermoelectric devices.

The facile control of the microdomain orientation in the liquid-crystalline block copolymer (LC-BCP) thin films has been realized by means of micropore extrusion and introducing polydimethylsiloxane (PDMS), instead of complicated processes or costly apparatus. In extrusion process, the alignment can be recovered via ultrasonicating the extruded BCP solution or as-placing upon long-time thermal annealing.

Self-assemble introduction of α-glucan contained block copolymer materials into the particular layer of the memory devices have been impressed by their excellent performance. Some newly reported MH-based copolymer literatures in electronic application are discussed in this focus review, including the electron-trapping mechanism of oligosaccharide MH, the relationships between chemical structures and their supramolecules, self-assembly morphologies and the memory device characteristics of electronic devices. As a perspective, the glucose-based block copolymer materials have a great potential to develop into the greener generation for advanced green electronics.

We reviewed the recent progress in the development of micro/nanofibrillar scaffolds for biomedical applications. We demonstrated the significance and essential information on four different micro/nanofibrillar scaffolds: (1) solid micro/nanofibrillar scaffolds (2) hydrogel nanofibrillar network scaffolds based on bacterial cellulose, (3) hydrogel micro/nanofiber scaffolds based on partially precipitated PVA, and (4) hydrogel micro/nanofiber scaffolds based on cross-linked PVA. This review would guide researchers for selecting a proper scaffold suitable for their own purposes and developing more sophisticated scaffolds.

Intracellular structures and function are tightly interwoven. Recapitulation of such intracellular microenvironments may enable novel biomimetic material synthesis and bioanalysis. Cell-inspired microanalysis platforms can be constructed by combined top-down microfabrication and bottom-up molecular self-assembly. Microcompartments of phase-separated aqueous solutions also play a critical role in biological processes. The biphasic microdroplets provide a unique analytical platform that conventional homogeneous bulk environments fail to achieve.

This review summarizes the recent advances in surface-coated single-walled carbon nanotubes as near-infrared nanometer-sized photoluminescent emitters for single-particle imaging and tracking applications in complex biological environments. It is focused on demonstrating surface coating identification, excitation strategies comparison, and long-term single-nanotube tracking inside the brain extracellular space in the live brain tissue.

Highly sensitive and rapid biosensing on a three-dimensional polymer platform. Increasing sensitivity and decreasing assay time are two of the most crucial goals in the development of biosensing devices. We have developed three-dimensional (3D) nanospherical and microfiber structure for biosensing devices aimed at highly sensitive and rapid immunoassays. The system having polystyrene microfiber of 3D structure paired with vacuum pump pressurization to induce bulk flow enables an efficient and rapid immunoassay. Because it takes advantage of the increased amount of immobilized antibody on 3D structure and of the accelerated propagation of antigens by flowing through the microfiber.

Our recent studies on the development of conjugated polymer synthesis via direct arylation polycondensdation (DArP) are summarized. Based on an appropriate molecular design and adjustment of the catalytic system for DArP, a variety of conjugated polymers, such as low-band-gap polymers with the strong acceptor moieties and regioregular poly(3-hexylselenophene) are successfully synthesized. These results demonstrate potential and utility of DArP as an alternative conjugated polymer synthesis methodology.

Theoretical models for thermo-sensitive hydrogels in pure water and in mixed solvent of water and methanol, and for thermo-sensitive copolymer in water are developed based on the concept of cooperative hydration of thermo-sensitive water-soluble polymers. The high-temperature collapse in water and the reentrant volume phase transition in water/methanol mixtures of poly(N-isopropylacrylamide) gels, and the phase behavior of statistical random copolymers of N-isopropylacrylamide and N,N-diethylacrylamide are theoretically studied.

Amphiphilic C₃-symmetric tris-ureas self-assemble into supramolecular hydrogels in aqueous solution. These supramolecular hydrogels were used as matrices for the electrophoresis of biopolymers (SUGE: SupramolecularGelElectrophoresis). A unique separation mode in comparison to that of SDS–PAGE was found during the electrophoresis of denatured proteins. Native proteins were separated on the basis of their isoelectric points and retained their activities. Large DNA fragments that previously had been separated only by pulsed-field gel electrophoresis were separated using a supramolecular hydrogel matrix and a typical continuous-field electrophoresis apparatus.

This review focuses on recent developments in the study of photosensitive engineering plastics based on reaction development patterning (RDP). RDP is a method of forming a fine pattern by promoting the reaction between carboxylic acid derivatives in a polymer chain and nucleophiles in a developer selectively at the exposed or unexposed area. Since engineering plastics such as polyimide and polycarbonate inherently have carboxylic acid derivative groups, RDP can impart photosensitivity to various polymers, including commercially available engineering plastics. Both positive- and negative-tone patterns can be formed by using RDP.

This review focuses on our novel approaches for developing functional polymers by dissociation phenomena of macromolecular complexes. One is highly swellable polymer gels, superabsorbent polymers for nonpolar organic solvents, and the other is thermo-responsive polymers at ambient temperature in nonpolar solvents. Both of them are well-known in water, but no design has ever been proposed for other media. The dissociation of the macromolecular complexes plays a key role for them. Therefore, controlling the dissociation processes in supramolecular chemistry should be another important strategy for emerged dynamic functions.