Facile synthesis of thermal-responsive P(NIPAM-S)/SiO2 hybrid hollow spheres and their controllable release properties for fragrance

Abstract

In this paper, thermal-responsive poly(n-isopropyl acrylamide-co-styrene) (P(NIPAM-S))/SiO₂ hybrid hollow spheres were successfully synthesized via a one-step method. In this approach, when P(NIPAM-S) colloidal particles were used as templates and encapsulated by SiO₂ nanoparticles derived from the sol–gel reaction of tetraethoxysilane under alkaline conditions, P(NIPAM-S)/SiO₂ hybrid hollow spheres were directly obtained. Neither calcinations nor an etching process was needed. Very interestingly, the as-obtained hybrid hollow spheres didn't exhibit typical thermal-responsive properties in aqueous solutions but rather in ethanol solutions, and thus could be used as controllable releasing systems in some specific environments.