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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.
Molecular entanglements (left) divide the crystalline and amorphous phases and are similar to the linked points that cause microphase separation in block copolymer (right). Our melt-drawing technique results in periodic arrangement of these phases and replaces the conventional paradigm of “entanglement exclusion for high performance” with the novel “entanglement utilization for high functionality”. In this review, our recent developments for nanostructured membranes using block copolymers and homopolymers are compared and reviewed based on their structural similarities.
This focus review describes that modular and hybrid molecular design approach used to introduce artificial chemical reactive groups into biomolecules or bio-related molecules enable the semi-rational construction of stimuli-responsive supramolecular systems.
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.
Recent advances in the study of active self-assembly utilizing biomolecular motors are reviewed. Various methodologies developed for demonstrating active self-assembly of biomolecular motors are discussed in detail with an emphasis on the morphological variations of the self-assembled structures.
We have successfully developed easy-to-use and rapid immunosensor devices based on extended-gate type polymer field-effect transistors (PFETs). The designed PFET was operated under low-voltage conditions, being able to apply for the detection of proteins in water. As a consequence, label-free detection of glycoproteins was achieved by the extended-gate PFETs functionalized with monoclonal or polyclonal antibodies. We believe that PFET-based immunoassays will be an attractive platform for on-site monitoring devices in healthcare applications in the near future.
Direct arylation polycondensation has been investigated to develop efficient synthetic methods of conjugated polymers for use in optoelectronic applications. The optimization of reaction conditions achieved high molecular weights and minimal structural defects in the recurring structures. The optimized direct arylation method has several advantages over conventional methods, e.g., fewer synthetic steps, and high-molecular-weight and high-purity polymer. The high-quality polymeric materials exhibited superior performance to those obtained using a conventional method when used in organic photovoltaics and field-effect transistors.
The liquid crystalline (LC) rod-like mesogens preferentially orient normal to the substrate plane due to the excluded volume effect (homeotropic alignment) in side-chain liquid-crystal (SCLC) polymers free-standing films. For in-plane alignment, a homeotropic orientation is unsuitable because the mesogens are in a direction opposite to the in-plane directions. This review focuses on new approaches to induce a random planar orientation in SCLC polymer systems by interface and surface molecular design utilizing a high-density polymer brush structure and surface segregation structures of block copolymers.
Interfacial morphologies and associated processes in multicomponent polymer systems, e.g., block copolymers (BCPs) and polymer blends, are examined using three-dimensional (3D) microscopies. Because of the rich structural information in 3D images, various new types of structural parameters, including chain conformation inside BCPs nanodomains, chain packing frustration in BCPs, Genus etc., can be obtained. The stability and interfacial dynamics are also discussed.
Flavin catalysts are typically metal-free, and their catalytic activity can be readily accessed using mild terminal oxidants such as H2O2 and O2; therefore, redox reactions with these compounds have great promise as alternatives to reactions with conventional metal catalysts for the sustainable production of important chemicals. Herein, our recent research on flavin catalysts including the development of facile preparation methods for flavin catalysts using polymers, readily reusable polymer-supported flavin catalysts, and flavin-peptide-polymer hybrids that can catalyze the first flavoenzyme-mimetic aerobic oxygenation reactions is summarized.
This focus review addresses recent progress on plant oil-based functional polymers and composites. An environmentally benign coating system is demonstrated using plant oils as the starting substrate for the preparation of artificial urushi with high hardness and a high gloss surface. Epoxidized plant oils are polymerized with designed inorganics, cellulose, and biodegradable aliphatic polyesters to afford functional biobased polymers and composites. Castor oil is used as the core of branched poly(lactic acid) to improve the physical properties of biobased plastics.
Preparation of Polymer Brushes with Well-Controlled Stereoregularity and Evaluation of Their Functional Properties High-density poly(methyl methacrylate) (PMMA) brushes with well-controlled stereoregularity were prepared using a surface-initiated living anionic polymerization method in the presence of a Lewis acid. A molecular weight range from 6 K to 400 K with a narrow polydispersity index (PDI) was obtained. Grazing incidence wide-angle X-ray diffraction measurements indicated that the polymer brushes formed a helical structure approximately 1 nm in diameter and consisting of encapsulated functional molecules or polymers, leading to the formation of inclusion complexes or stereocomplexes.
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.
A new nucleic acid delivery framework, predicated on a photo-responsive cationic block copolymer (BCP), was used to precisely tune nucleic acid binding and provide spatiotemporal control over gene expression. This innovative platform leveraged a macromolecular design in which the polymer moieties directly responsible for nucleic acid complexation were cleaved from the polymer upon photo-stimulation, significantly enhancing nucleic acid release. Temporal control over polyplex disassembly facilitated development of a potentially universal, kinetic modeling scheme for gene silencing. Furthermore, this versatile BCP-based framework easily accommodated anionic excipients and quantum dot imaging constructs.
Soft materials based on colloidal self-assembly in ionic liquids: fundamental studies on the colloidal stability in ionic liquids (ILs) are highlighted. Three different repulsive forces—electrostatic, solvation, and steric—are examined for their effectiveness to stabilize colloidal particles in ILs. An overview of recent studies on colloidal soft materials in the presence of ILs is also provided. Based on suspended states of colloid particles, two different soft materials—colloidal gel and colloidal glass—were prepared in ILs. Their functional properties, including ionic transport, rheological and optical properties, are discussed in relation to the microstructures of the colloidal materials.
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.
A chromatography-free procedure for the preparation of monodisperse monotosylated PEGs allowed for the preparation of 8- to 16-mers in relatively large quantities in good yields and purities and facilitates the investigation of PEG-based functional molecules such as structured PEGs, which had specific two-dimensional shapes. For example, the triangular molecule dehydrated at a lower temperature than linear compounds with a similar molecular weight and can suppress aggregation of proteins at high temperatures. It was also found that the introduction of an aromatic group in the PEG skeleton lowered the dehydration temperature.
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.
A recent progress of phenanthro[1,2-b:8,7-b′]dithiophene (PDT)-based low bandgap semiconducting polymers combined with various strong acceptor units are described. By incorporating a highly π-extended PDT core into the polymer backbone, the synthesized polymers have deep HOMO energy levels and formed a dense packing structure with a short π-stacking distance. The PDT-based polymers with optimal side chains and high molecular weight exhibit high hole mobility of up to 0.18 cm−1 V−1 s−1 in organic field-effect transistors and high power conversion efficiency over 6%. These results indicate that PDT is a good π-framework as high-performance semiconducting 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.
