Synthesis of hyperbranched polysiloxane/poly(N-isopropylacrylamide) microgel, its stimulus responsive behavior and study for drug release

In the present study, a novel thermo-responsive microgel with aggregation induced emission (AIE) based on hyperbranched polysiloxane (HBPS) as the AIE-active luminogen, its thermo-responsiveness and application in controlled release of drug is firstly reported. Firstly, HBPS was prepared by transesterification, and then it was copolymerized with N-isopropylacrylamide (NIPAm) to prepare microgel of hyperbranched polysiloxane/poly(N-isopropylacrylamide) (HBPS@PNIPAm) by free radical copolymerization. The microstructure of the as-prepared microgel was characterized, and its behavior of drug loading and release was researched by PL with Luteolin as model drug. The results showed that the microgel had the thermo-response enhanced by AIE-active fluorescence with increasing temperature, its fluorescence emission could be adjusted by environmental temperature, or content of Luteolin loaded in the microgel, and the drug loading or release properties of Luteolin could be detected easily by fluorescence spectrum of microgel.