Microflow synthesis of stimuli-responsive star polymers and its application on catalytic reduction

In cascade microreactor systems, a series of star polymers , in which poly(di(ethylene glycol) ethyl ether acrylate-co-oligoethylene glycol acrylate) served as the thermoresponsive arm and poly(N, N-dimethylaminoethyl acrylate) as the pH-responsive arm, were successfully prepared via the RAFT arm-first method. Results showed that the compositions of star products were close to the designed feed ratios, and the lower critical solution temperature (LCST) was affected by the arm composition and the external pH. Due to the more compact structure, star polymers had a smarter temperature response than the linear chains. Moreover, the Au nanoparticles formed by coordination reduction of star products could be efficiently applied in the 4-nitrophenol catalytic reduction process, and the reaction rate was affected by the arm composition, pH and temperature. This research demonstrated that polymer products with particular functions could be customized by tailoring the polymer structures in a facile microflow polymerization mode.