Influence of ionic liquid modified gold nanoparticles on conformational transition of poly(N-isopropylacrylamide)-b-poly(acryloylmorpholine) block copolymer

Utilizing stimuli-responsive polymers for surface modification of nanoparticle allows the adjustment of properties for individual system; however, limited research explores the impact of ionic liquid-modified gold nanoparticles (AuNPs) on the conformational phase transition of block copolymers. Herein, we synthesized poly(N-isopropylacrylamide)-b-poly(acryloylmorpholine) (PNIPAM-b-PACMO) copolymers by reversible addition − fragmentation chain-transfer polymerization and investigated the effect of ionic-liquid modified AuNPs (IL-AuNPs) on the aggregation behavior of the copolymer. Copolymerization of PNIPAM with PACMO shifted the lower critical solution temperature (LCST) towards higher temperature in comparison to LCST value of PNIPAM. Addition of IL-AuNPs further raises the transition temperature in concentration dependent manner. A more significant alteration in the transition temperature was observed in the presence of IL-AuNPs with a higher alkyl chain length. The variation in transition temperature of the copolymer by different IL-AuNPs yields benefits in the temperature responsive properties which can helpful for various applications.