Surface-initiated RAFT polymerization from vapor-based polymer coatings

Surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization was used to synthesize poly(methyl methacrylate) (PMMA) and poly[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammoniumhydroxide (PMEDSAH) brushes grafted from reactive poly[p-xylylene] surfaces. The synthetic approach involved functionalization of substrates via chemical vapor deposition polymerization of an electron-deficient alkynyl-functionalized [2.2]paracyclophane derivative. An azide-functionalized RAFT agent was anchored to the resulting poly[(p-xylylene-4-methyl propiolate)-co-p-xylylene] films via copper-free click-chemistry. Subsequent SI-RAFT polymerization yielded PMMA and PMEDSAH films with narrow dispersity which was further tuned by varying the concentration of a sacrificial RAFT agent in solution. Polymer dispersity was determined by size exclusion chromatography to be in the range of 1.2-1.4 for both polymers. This work provides a novel surface modification strategy to decorate a wide range of different substrates with polymer brushes, thereby eliminating the need for cumbersome modification protocols, which so far had to be established for each substrate material independently. (C) 2018 Elsevier Ltd. All rights reserved.