Institute of Chemical Engineering and High‐Temperature Chemical Processes, ICE/HT‐FORTH, University of Patras, P.O. Box 1414, 26504 Patras, Greece
Abstract:
An asymmetric, amphiphilic, An(B‐b‐C)n heteroarm star block terpolymer bearing polystyrene and poly(2‐vinyl pyridine)‐block‐poly(acrylic acid) arms, was synthesized by anionic polymerization, using an extending “in‐out” method and a post polymerization deprotection reaction. Due to the pH‐dependent protonation/deprotonation equilibrium of the P2VP/PAA blocks, a rich phase behavior was observed as a function of pH. At pH = 2, the star terpolymers form a physical hydrogel through a solvent‐induced sol/gel transition in a DMF/water solvent mixture. The gelation mechanism was attributed to a jamming effect mediated by increasing the dielectric permittivity of the medium.
