Stimuli-Sensitive Composite Microgels

Abstract

Poly(N-isopropylacrylamide) (PNIPAM) microgels were prepared by precipitation polymerization and PNIPAM shell / hard core particles were obtained by soap-free emulsion copolymerization or seeded polymerization. Hairy particles were prepared by “grafting-to” modification or “grafting-from” living radical polymerization. They exhibited not only volume phase transition but also changes in some physical properties in a certain temperature range. Composite thermosensitive microgels including magnetite, Au, or titania were obtained by in situ formation of metal or metal oxide in polymeric particles. The functions of metal or metal oxide were tuned by reversible volume phase transition of the microgel as a function of temperature. Enzyme-carrying thermosensitive microgels exhibited unique temperature-dependence of enzyme activity.