Azobenzene-Containing Molecularly Imprinted Polymer Microspheres with Photo- and Thermoresponsive Template Binding Properties in Pure Aqueous Media by Atom Transfer Radical Polymerization

摘要

A facile, general, and highly efficient approach tonobtain azobenzene (azo)-containing molecularly imprinted polymern(MIP) microspheres with both photo- and thermoresponsiventemplate binding properties in pure aqueous media is describednfor the first time, which involves the first synthesis of “living” azocontainingnMIP microspheres with surface-immobilized alkyl halidengroups via atom transfer radical precipitation polymerizationn(ATRPP) and their subsequent modification via surface-initiatednatom transfer radical polymerization (ATRP) of N-isopropylacrylamiden(NIPAAm). The successful grafting of poly(NIPAAm) (PNIPAAm) brushes onto the obtained MIP microspheres wasnconfirmed by FT-IR, SEM, water dispersion stability and static contact angle studies, and template binding experiments. Thenintroduction of PNIPAAm brushes onto the azo-containing MIP microspheres significantly improved their surface hydrophilicitynand imparted thermoresponsive properties to them, leading to their pure water-compatible and thermoresponsive templatenbinding properties. In addition, the binding affinity of the imprinted sites in the grafted azo-containing MIP microspheres wasnfound to be photoresponsive toward the template in pure water, and this photoregulation process proved to be highly repeatablenunder photoswitching conditions.