Volume 50 Issue 7, July 2018

A versatile and simple strategy for building self-healing hydrogels with tunable mechanical properties and shape memory behavior has been developed using diethylenetriamine to crosslink polyacrylic acid chains. Hydrophobic domains form in the network in addition to ionic bonds between the amino and carboxylic acid groups. The combination of ionic bonds and hydrophobic interactions not only provides self-healing ability but also drastically improves the strength.

We report a facile method for synthesizing Au NPs based on alkali/urea regenerated cellulose hydrogels. By controlling the precursor concentration and the reaction temperature, the size of the Au NPs can be adjusted. The Au NP/cellulose hydrogels can be used as efficient heterogeneous catalysts in the reduction of 4-nitrophenol.

Poly(N-isopropylacrylamide) nanogels having catechol substituents were prepared. It was found that the aqueous dispersion of the nanogel showed thermal aggregation responding to body temperature only in the case that Fe³⁺ was mixed and then pH increased. It can be said that this thermal aggregation system of the nanogel is one kind of AND-type logic gate aggregation system. We also showed the possibility that this AND-type nanogel aggregation can be used as a smart valve system regulating water flow.

6 groups of blend membranes based on carboxymethyl chitosan (CMCTS) or carboxymethyl chitin (CMCT) were prepared. CMCTS-Gel (1#) and CMCT-Gel (4#) blend membranes with high transmittance and surface properties were more suitable for cell growth. Although primary corneal epithelial cells (CECs) on the two blend membranes could keep marker proteins and prevent cell fibrosis, CECs on membrane 4# could maintain the original epithelial morphology and improve the K12 protein level seriously. The potential mechanism of anti-fibrosis effect was proved that both of the membranes could block phosphorylation levels of Smad2 and Smad3, and membrane 4# could also depress the total native Smad2 and Smad3 expressions.

Glycosylated double-hydrophilic block copolymers composed of polyacrylamide bearing maltose moieties and poly(N-isopropylacrylamide) were synthesized by a RAFT polymerization technique. The resulting glycosylated block copolymer aggregated, interacted strongly with the lectin Con A, and formed a precipitate in aqueous media above the LCST. The precipitate dissociated into the aqueous medium below the LCST. This behavior of the block copolymer in aqueous media is reversible in response to changes in temperature.

For THF solutions of an optically active helical poly[3,5-bis(hydroxymethyl)phenylacetylene] derivative bearing a biphenyl group, photoexcitation of the terphenyl moiety at 300 nm led to photoluminescence at 390 nm. On the other hand, the photoluminescence resulting from excitation at 280 nm caused dual emission at 310 and 390 nm, whose intensities were tuned by the polar-solvent stimuli which induced the collapse of the intramolecular stack structure of the side groups, and the change in the emission wavelength accompanied disappearance of the optical activity.