Well‐defined <i>N</i>‐Isopropylacrylamide Dual‐Sensitive Copolymers with LCST ≈38 °C in Different Architectures: Linear, Block and Star Polymers

Abstract

Abstract Reversible addition‐fragmentation chain transfer (RAFT) polymerization is used to prepare temperature‐ and pH‐sensitive statistical copolymers with lower critical solution temperature (LCST) close to 38 °C at pH 7.4 based on N ‐isopropylacrylamide and methacrylic acid derivative comonomers with a p K a close to 6. Statistical copolymers are re‐activated to prepare amphiphilic block copolymers and star polymers with cross‐linked core. The LCST is maintained by varying the architecture; however, the LCST originated behaviour changes due to self‐aggregation. Statistical copolymers and short block copolymers show complex aggregation, whereas mid‐size block copolymers and star polymers show shrinkage of aggregate dimensions. The pH of the medium has a profound impact on the self‐assembling behaviour of the different polymer architectures.