Thermoresponsive AIE polymers with fine-tuned response temperature

Abstract

A series of thermoresponsive AIE polymers were synthesized through the free radical copolymerization of the thermosensitive N-isopropylacrylamide (NIPAM) monomer, the regulative oligo(ethylene glycol) methacrylate (OEGMA) monomer or methyl methacrylate (MMA) monomer, and the fluorescent tetraphenylethene monomer. By adjusting the loading ratio of NIPAM and OEGMA/MMA, the hydrophilicity of the copolymers can be fine-tuned, which enables further modulation of the lower critical solution temperature (LCST) as well as the detection temperature range. Below the LCST, hydrogen bonds are formed between the polymer chain and water molecules, which leads to good solubility and weak emission of the polymers. Above the LCST, interchain or intrachain hydrogen bonds within polymers are favored to form emissive polymer aggregates.