Synthesis of Amphiphilic Block Copolymers Based on SKA by RAFT Polymerization

Abstract

AbstractTemperature‐sensitive amphiphilic block copolymers of 2,2‐dimethyl‐1,3‐dioxolan‐4‐yl‐methyl acrylate (solketal acrylate, SKA) and N‐isopropyl acrylamide (NIPAAm) have been prepared via reversible addition‐fragmentation chain transfer radical polymerization (RAFT). A kinetics study of SKA polymerization is performed in order to find a compatible RAFT chain transfer agents (CTA) and versatile polymerization conditions for the synthesis of well‐defined poly(2,2‐dimethyl‐1,3‐dioxolan‐4‐yl‐methyl acrylate) (PSKA). Depending on the RAFT‐CTA and the reaction time, PSKA with molar masses up to 5700 g mol−1 and dispersity values as low as 1.1 could be prepared. Additionally, the end group distribution of PSKA is investigated via electrospray ionization‐ion mobility separation–mass spectrometry. The chain extensions of the homopolymers for the second block of NIPAAm are analyzed with size‐exclusion chromatography. Amphiphilic block copolymers are obtained after hydrolysis of hydrophobic PSKA block to target hydrophilic poly(2,3‐dihydroxypropyl acrylate) block.