Preparation and characterization of dual stimuli-responsive microcapsules with a superparamagnetic porous membrane and thermo-responsive gates

A novel dual stimuli-responsive microcapsule with a superparamagnetic porous membrane and linear-grafted poly(N-isopropylacrylamide) (PNIPAM) gates in the membrane pores is successfully prepared and characterized. Oleic acid (OA)-modified Fe3O4 nanoparticles are embedded into the polyamide microcapsule membrane during interfacial polymerization process, and then plasma-induced grafting polymerization is used to graft PNIPAM into the pores of microcapsule membranes. The prepared microcapsule membranes exhibit time-independent superparamagnetic property with good magnetic-responsive ability, and satisfactory thermo-responsive controlled-release property due to the thermo-responsive swollen/shrunken property of PNIPAM gates grafted on the inner pore surface of the microcapsule membranes.