Multiple-Responsive Dendronized Hyperbranched Polymers

Abstract

By\ncombining topological structures of hyperbranched polymers with\ndendronized polymers, a series of hyperbranched poly­(acylhydrazone)­s\npendanted with 3-fold branched dendritic oligoethylene glycol (OEG)\nunits were efficiently prepared through A₂ + B₃ polycondensation. The constituents of these dendritic polymers can\nbe mediated through dynamic covalent acylhydrazones. Owing to the\ndense OEG pendants, these dendronized hyperbranched polymers are biocompatible\nand thermoresponsive, and their cloud points (<i>T</i>_cps) can be modulated by the branched architecture, solution\npH, and addition of a third component. Cell viability in the presence\nof these hyperbranched poly­(acylhydrazone)­s can be maintained above\n80%. Based on the unique dendritic architecture with rich acylhydrazine\ngroups, dynamic hydrogels cross-linked via acylhydrazone linkages\nwith good mechanical property were prepared, which inherit the characteristic\nthermoresponsive behavior of the polymer precursors and also show\nremarkable self-healing properties. This novel kind of topological\npolymers and their corresponding hydrogels with dynamic and multiple\nsmart properties may have promising applications as biomaterials.