Synthesis of Well-Defined Photo-Cross-Linked Polymeric Nanocapsules by Surface-Initiated RAFT Polymerization

Abstract

Narrowly distributed hollow polymeric nanocapsules (PtBMA-co-PDMIPM-b-PHPMA), with the size of 450 or 900 nm, were first synthesized by surface-initiated reversible addition–fragmentation chain transfer (RAFT) polymerization exploiting silica nanoparticles as sacrificial templates and 2,3-dimethylmaleic imidopropyl methacrylate (DMIPM) as a photo-cross-linker. First, silica nanoparticles were amino functionalized by aminosilane agents, and then the dithiocarbonate chain transfer agent (CTA) was anchored via activated R-groups to the amino-functionalized surface of silica nanoparticles. This surface layer of CTA groups was then used to grow linear copolymers and block copolymers by RAFT polymerization leading to a core–shell morphology. TEM and GPC results indicated that the thickness of the shell can be well governed by simply controlling the molecular weight of the grafted copolymer. Finally, after photo-cross-linking and etching the silica core with NH4F/HF buffer, hollow nanocapsules were obtained, of ...