Functionalization of Titanium Surfaces with Polymer Brushes Prepared from a Biomimetic RAFT Agent

Well-defined dopamine end-functionalized polymers were synthesized by employing the reversible addition fragmentation chain transfer (RAFT) polymerization technique. tert-Butyl acrylate, N-isopropylacrylamide, and styrene monomers were polymerized in the presence of azobis (isobutyronitrile) and a new catechol-based biomimetic RAFT agent incorporating a trithiocarbonate unit. All RAFT polymerizations exhibited pseudofirst-order kinetics, a linear increase of the number-average molar mass (M-n SEC) with conversion and narrow molar mass distributions (polydispersity <1.2). The resulting homopolymers exhibited the electroactive catechol and the omega-trithiocarbonyl end groups. Subsequent immobilization of dopamine end-functionalized polymers on titanium surfaces was monitored by using a surface plasmon resonance (SPR) sensor, and the resulting films were characterized by contact angle, infrared ATR spectroscopy, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS).