Acid-Degradable Poly(N-vinylformamide)/Polyvinylamine Nanogel Capsules

摘要

Acid-labile nanogel capsules were synthesized by free radical polymerization of N-vinylformamide on the surface of silica nanoparticles in the presence of a novel crosslinker that contains an acid-labile ketal. Stable etching of silica nanoparticle templates was achieved using sodium hydroxide allowing recovery of PNVF nanocapsules. The formamido side group of PNVF was then hydrolyzed by extended exposure to sodium hydroxide to produce acid-labile PVAm nanocapsules. Both capsule types demonstrated an increasing dissolution rate as pH decreased. In addition, PVAm nanocapsules exhibited swelling in proportion to the relative charge density of the PVAm network (a function of the degree of formamide hydrolysis and pH). The synthetic approaches reported provide methods to endow nanocapsules with key attributes such as size control, pH sensitive degradation, swelling in response to pH, and amine functionality.