Reviews & Analysis

Self-organization in nonequilibrium systems composed of a bulk filler powder and a bulk polymer melt as an initial state (i) into a final ordered state (f) in applied mechanical field occurs via cascade evolution of the dissipative structures (a) to (e) accompanied by the cascade energy dissipation processes [Process (I) and Process (II)]. These processes also induce the relevant cascade changes in free energy and stress level.

Designer supramolecular polymers are a growing field of polymer materials. The designability and flexibility in their structures and functionality have attracted a great deal of attention in polymer science, as well as in supramolecular chemistry. These polymeric structures are formed from one or more molecular components via reversible bonds; therefore, monomeric and polymeric states are in equilibrium on the relevant experimental timescale. The dynamic nature of supramolecular polymers in terms of chain lifetime and conformational flexibility are determined by external conditions. This adaptivity can result in stimuli-responsive structures and properties. This article describes the use of our host–guest structures based on a calix[5]arene, a bisporphyrin, and a self-assembled capsule in the synthesis of supramolecular polymers.

Among various approaches to create self-healing polymers, the introduction of dynamic bonds to polymers is one of the most powerful approaches. However, since the reformation of dynamic bonds requires molecular mobility, mechanical strength usually conflicts with an autonomous healing ability. In this review, we overview recent successful approaches to overcome this limitation, as well as attempts to design mechanically robust polymers that can heal with the assistance of ubiquitous stimuli. These approaches include combining careful dynamic bond chemistry choices and smart designs of the environment around the dynamic bonds.

Recent works revealed that protein and cell resistance of bioinert self-assembled monolayers originates in the physical barrier of the interfacial water. We review the history of the previous works that attempted to clarify the underlying mechanism and discuss prospects to apply the findings to design new biomaterials.

This review deals with the synthesis of various polymers carrying bulky and rigid adamantyl substituents in the side chain. The synthetic methods of those polymers include the typical polymer reaction by introducing adamantyl groups to the present polymers and the polymerization of the monomers bearing the adamantyl pendant groups. A variety of vinyl monomers, such as styrenes, 1,3-butadiene, and (meth)acrylates, are capable of the living anionic polymerization to afford the polymers having predictable molecular weights and narrow molecular weight distributions (Mw/Mn =1.1). The resulting adamantyl-substituted polymers show extremely high glass transition temperatures and high thermal stability derived from the stiff adamantyl substituents compared with the corresponding parent polymers.

Amphiphilic block polymers having nitroxide radicals (TEMPO) self-assemble in water to form nanoparticles. This is a new nanomedicine that avoids the adverse effects of conventional antioxidants, which destroy the intracellular redox environment, and makes it possible to treat various oxidative-stress-related diseases such as cerebral or cardiovascular ischemia-reperfusions, Alzheimer’s disease and cancer. In addition, we have designed a gelation function in these materials and developed them as a material for anti-tissue adhesion agents and periodontal diseases. Additionally, we succeeded in enhancing cultured cell functions using an antioxidant biointerface.

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.

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.