Full pH-range responsive hyperbranched polyethers: synthesis and responsiveness†
In order to impart full pH-range responsiveness within biocompatible hyperbranched polyethers, new amphiphilic polyethers, i.e. HPMHO–Amines and HPMHO–Carboxys, which have a molecular structure similar to hyperbranched PEG, were prepared through ring-opening polymerization and modified by amination or carboxylation. Because of the existence of hydrophobic core and ionization of weak acidic and basic groups on the surface, these hyperbranched polyethers showed reversible pH-response in aqueous solution. The responsive pH values covered the complete pH range and could be readily adjusted by only changing the degree of modification. Cellular experiments showed that these pH-responsive hyperbranched polyethers had low cytotoxicity, indicating this novel full pH-range responsive hyperbranched polyether would be a promising functional material for physiological and pH-relevant bio-applications.