Functionalization of gold and silicon surfaces by copolymer brushes using surface-initiated ATRPa

Surface-initiated ATRP was used for step-by-step growth of poly(butyl methacrylate)co-poly(2,2-dimethylaminoethyl methacrylate) (PBMA-co-PDMAEMA) brushes from gold and silicon substrates. A one-step procedure was found to have high efficiency for initiator anchoring. The polymer brushes were characterized in situ by contact angle measurements ellipsometry, and X-ray photoelectron spectroscopy (XPS). Detachment of the polymer brushes from both substrates allowed an exact determination of molecular weight and polydispersity indexes given by GPC. H-1 NMR confirmed the chemical structure of the detached brushes. Comparison of theoretical predictions and experimental data showed that the first PBMA block had a folded conformation while copolymerization of the second DAAAEMA induced stretching of the brushes.