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Novel aromatic copolymers based on a thiazolothiazole (TT) unit were designed and synthesized as proton exchange membranes for polymer electrolyte fuel cells. Even a small amount of the TT unit (0.1–1 mol%) considerably affected the sizes of the hydrophilic and hydrophobic domains of the membrane surface. Furthermore, the TT-based membranes exhibited higher proton conductivities and lower activation energies than those of the parent membrane under various relative humidity conditions.
Our recent studies on the nano- and micro-structured molecule-responsive hydrogels are summarized. The nano- and micro-structured molecule-responsive hydrogels exhibited rapid swelling/shrinkage behavior in response to a target molecule based on the association/dissociation of molecular complexes that act as crosslinkers. In addition, these hydrogels showed smart functions, such as autonomous molecule-responsive microchannel flow regulation and highly sensitive detection of a target molecule. The smart functions of nano- and micro-structured molecule-responsive hydrogels can provide tools for constructing sensors, microdevices and smart biomaterials.
Recently, we have developed a simple and green approach to surface wrinkling via lignification mimetic reaction and drying. A skin layer is synthesized on a chitosan film via immersion in a methanol solution containing a phenolic acid and subsequent surface reaction by horseradish peroxidase, mimicking wood lignification. A surface relief with micron-scale wrinkles is formed upon drying and as a result of inhomogeneous shrinkage. This focus review overviews this innovative approach and its detailed mechanism.
The phase behaviors of the as-prepared poly(3-dimethyl(methacryloyloxy-ethyl)ammonium propane sulfonate betaine (polySBMA) solutions at high concentrations were investigated. The solution exhibited stably reversible phase transition between transparency and opacity. The transition temperature decreased with the increase of the polymer concentrations. The polySBMA had a high equilibrium concentration, which results in the as-prepared polySBMA solution with a high concentration presented an over-swelling behavior that played an important role in the transition temperature of the solution.
We designed a thermosetting polyurethane based on the reversible reaction between isocyanates and phenolic hydroxyls instead of alcoholic hydroxyls. The phenolic urethane partially decomposed at above 120 °C, but the phenolic hydroxyl and isocyanate reconnected upon cooling. This reversible urethane bond contributed to the thermal self-repair of the thermosetting polyurethane network and can be applied into self-healing coatings or adhesives.
The scalability and recyclability in transesterifications of polysaccharides with 1-ethyl-3-methylimidazolium acetate (EmimOAc) as both the solvent and organocatalyst was confirmed. In addition, the EmimOAc-catalyzed transesterification protocol was expanded to a gram-scale reaction with various polysaccharide sources, such as pulps, rayon, xylan, pululan, and dextrin.
The corneal endothelial scaffolds were prepared using carboxymethyl chitin (CMCT) or carboxymethyl chitosan (CMCTS) as the main ingredient. The transmittances of the membranes were examined at different wavelengths. The properties of both membranes, including cytotoxicity, histocompatibility, degradability and cytocompatibility, were determined by experiments on cultured cells or rats. By contrast, the CMCT membrane proved to be a more promising candidate for constructing CEC endothelial scaffold.
