Well-Controlled Formation of Polymeric Micelles with a Nanosized Aqueous Core and Their Applications as Nanoreactors

Abstract

Polymeric micelles with a polystyrene (PS) shell and a protonated poly(4-vinylpyridine) (P4VP)/water core were readily prepared via diffusion of HCl and water from the top aqueous phase containing HCl (pH = 1) into the bottom phase of the PS-b-P4VP solution in chloroform. The resultant protonation of the pyridine units of the P4VP block drove the micellization. Meanwhile, due to the high polarity of the core, water molecules also diffused through the chloroform medium into the core. 1H NMR characterizations demonstrate that at the early stage, the water molecules in the core are the bound and intermediate water; longer diffusion times resulted in the appearance of free water molecules coexisting with the bound and intermediate water in the core. Thus, polymeric micelles with an aqueous core (PMACs) were formed. The process of forming PMACs is well-controllable, and the stability of PMACs in chloroform is high. These characteristics make PMACs promising as nanoreactors to prepare inorganic nanoparticles or...