Converting Poly(Methyl Methacrylate) into a Triple‐Responsive Polymer

Multiresponsive polymers that can respond to several external stimuli are promising materials for a manifold of applications. Herein, a facile method for the synthesis of triple‐responsive (pH, temperature, CO(2)) poly(N,N‐diethylaminoethyl methacrylamide) by a post‐polymerization amidation of poly(methyl methacrylate) (PMMA) is presented. Combined with trivalent counterions ([Fe(CN)(6)](3−)) both an upper and lower critical solution temperature (UCST/LCST)‐type phase behavior can be realized at pH 8 and 9. PMMA and PMMA‐based block copolymers are readily accessible by living anionic and controlled radical polymerization techniques, which opens access to various responsive polymer architectures based on the developed functionalization method. This method can also be applied on melt‐processed bulk PMMA samples to introduce functional, responsive moieties at the PMMA surface.