Switchable catalytic activity of poly (N-isopropylacrylamide-b-lauryl acrylate) supported AuNPs in the reduction in p-nitrophenol

In this work, poly (N-isopropylacrylamide-b-lauryl acrylate) (PNIPAM-b-PLA) as an intelligent polymeric micelle, which is temperature-sensitive, was successfully synthesized via the RAFT polymerization method, allowing precise control over molecular weight. Initially, PNIPAM was synthesized and then applied as a macro chain transfer agent for the polymerization of lauryl acrylate. Subsequently, the block copolymer was decorated with gold nanoparticles (AuNPs) to produce PNIPAM-b-PLA/AuNPs. The catalytic activity of temperature-sensitive Au catalyst was examined in the hydrogenation of p-nitrophenol to p-aminophenol as a model reaction. Notably, the catalytic activity could be modulated during the reduction reaction by adjusting the temperature, below or above the lower critical solution temperature (LCST) of the polymeric micelle. The catalytic activity of this “smart” Au catalyst can be switched “on” and “off” below and above the LCST of the block copolymer, respectively. Furthermore, the catalytic system exhibited efficient recovery for up to five cycles with minimal Au leaching.