Preparation of thermosensitive PNIPAM microcontainers and a versatile method to fabricate PNIPAM shell on particles with silica surface

Thermosensitive PNIPAM microcontainers were prepared by using silica particles as template. Silica particles were prepared by the Stober method and surface modified with linear P(NIPAM-co-MPS) chains. PNIPAM shell was then fabricated on the P(NIPAM-co-MPS)-modified silica particles through precipitation polymerization of NIPAM and MBA. Finally, PNIPAM microcontainers were obtained by removing the silica cores with NaOH. The materials were characterized by TEM, FTIR, GPC, and DLS. The PNIPAM microcontainers exhibit good thermosensitivity. The method to fabricate thermosensitive PNIPAM shell can be generalized to a versatile method for preparing PNIPAM shell on particles with silica surface, which includes surface modification with P(NIPAM-co-MPS) and precipitation polymerization of NIPAM and MBA using the modified particles as seed. Through this method, PNIPAM shell was successfully fabricated on iron oxide/silica nanostructures with a wormlike shape and relatively large size, which demonstrates the versatility of the method.