Session: POLY/PMSE Poster Session:

We expand the monomer scope of our universal approach to grow high grafting density polymer brushes from a variety of substrates by switching atom transfer radical polymerization (ATRP) initiating sites to chain transfer agent (CTA) sites for surface-initiatied reversible addition-fragmentation chain-transfer (SI-RAFT) polymerization. We previously developed an ultrathin, single-component inimer coating made of a copolymer of ATRP inimer and glycidyl methacrylate (GMA). The copolymer is spin-coated and thermally crosslinked into a 5 nm inimer coating. This coating is then used for SI-ATRP of high-density polymer brushes. In this work we demonstrate that the ATRP initiator can be efficiently switched to RAFT initiator after crosslinking of the film to enable SI-RAFT, while maintaining density of the brushes, uniformity of grafting sites, and predictable chain length. Hence, monomers such as vinyl pyridines that cannot be easily grown by SI-ATRP can now be grown by SI-RAFT, vastly expanding the monomer scope. We further exploit this chemistry to grow A/B mixed polymer brushes via SI-NMP and SI-RAFT, from a coating composed of a copolymer of ATRP inimer, NMP inimer and GMA. Unlike growth of polymer brushes via self-assembled monolayer of initiators, the inimer coating results in a high grafting density of >0.7 chains/nm². We study the resulting morphology in a high chi A/B mixed brush system.

Padma Gopalan

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