Synthesis and Aggregation Behaviors of Well‐Defined Thermoresponsive Pentablock Terpolymers With Tunable LCST

Abstract

AbstractA series of thermoresponsive pentablock terpolymers, poly(N‐isopropylacrylamide)‐b‐poly(ethylene oxide)‐b‐poly(propylene oxide)‐b‐poly(ethylene oxide)‐b‐poly(N‐isopropylacrylamide), is prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization. The effect of NIPAM and PPO block lengths on lower critical solution temperature (LCST), critical micelle concentration (cmc), and aggregation number (Nagg) is investigated via UV–Vis spectroscopy and steady‐state fluorescence spectroscopy. The results show that upon increasing the block lengths, LCST and cmc decrease, while Nagg increases. TEM observation shows that associated spherical‐like particles are evidenced below the LCST of the terpolymers, and regular or irregular spherical micelles or even intermicellar aggregates are observed above the LCST.