CREATION OF STABLE POLY(ETHYLENE OXIDE) SURFACES ON POLY(METHYL METHACRYLATE) USING BLENDS OF BRANCHED AND LINEAR-POLYMERS

Thin film miscible blends of poly(methyl methacrylate) (PMMA) and a br anched random copolymer of methyl methacrylate and methoxy poly(ethyle ne glycol) monomethacrylate, P(MMA-r-MnG), were investigated by neutro n reflectivity. The branched copolymer, which has a higher surface ten sion than PMMA, was nevertheless found to segregate to and completely cover both the surface and silicon substrate following annealing in 20 00 Angstrom thick films with greater than or equal to 2 wt % P(MMA-r-M nG). This is in contrast to linear polyethylene oxide, which was deple ted at both film interfaces when blended with PMMA and annealed. The r eflectivity results were confirmed by contact angle studies, which ind icate that the surfaces of P(MMA-r-MnG)/PMMA blends behave like that o f pure P(MMA-r-MnG), resulting in a hydrophilic surface that is stable against dissolution in water-based environments. The branched hydroph ilic additive is further shown to render PMMA resistant to protein ads orption and cell adhesion.