Homopolymer and block copolymer brushes on gold by living anionic surface-initiated polymerization in a polar solvent

Living anionic surface-initiated polymerization on flat gold substrates has been conducted to create uniform homopolymer and diblock copolymer brushes. A 1,1-diphenylethylene (DPE) self-assembled monolayer was used as the immobilized precursor initiator. n-BuLi was used to activate the DPE in tetrahydrofuran at -78 °C to initiate the polymerization of different monomers (styrene, isoprene, ethylene oxide, and methyl methacrylate). Poly(styrene) (PS) and poly(ethylene oxide) (PEO) in particular were first investigated as grafted homopolymers, followed by their copolymers, including poly(isoprene)-b- poly(methylmethacrylate) (PI-b-PMMA). A combined approach of spectroscopic (Fourier transform infrared spectroscopy, surface plasmon spectroscopy, ellipsometry, X-ray photoelectron spectroscopy) and microscopic (atomic force microscopy) surface analysis was used to investigate the formation of the polymer brushes in polar solvent media. The chemical nature of the outermost layer of these brushes was studied by water contact angle measurements. The effect of the experimental conditions (solvent, temperature, initiator concentration) on the surface properties of the polymer brushes was also investigated.