Thin, highly crosslinked polymer layer synthesized via photoinitiated graft copolymerization on a self-assembled-monolayer-coated gold surface

A thin, highly crosslinked layer was grafted onto an alkyl thiol self-assembled-monolayer (SAM)-coated gold surface with N,N'-methylene bisacrylamicle (MBAA), a widely used crosslinker with two polymerizable groups, as the monomer. Surface-initiated photografting copolymerization was achieved through the immobilization of the hydrogen-abstraction photoinitiator benzophenone on the hydrophobic alkyl surface via physical adsorption and subsequent UV irradiation in the presence of an MBAA solution. The growth of the grafted poly-MBAA layers seemed to produce dendritic structures with low surface coverage. At a higher monomer concentration (15 g/L of water), full coverage of the gold surface with a thin layer was obtained and proved by scanning force microscopy and contact-angle measurements. The evaluation of the gold, gold-SAM, and gold-SAM/grafted poly-MBAA layers with a surface plasmon resonance sensor system revealed that the photografted, thin, highly crosslinked polyacrylamide layers had a very low affinity toward the adsorption of protein. Therefore, this provides a very promising approach to tailoring materials for sensors and other applications. (c) 2005 Wiley Periodicals, Inc.