Functionalization of Gold and Silicon Surfaces by Copolymer Brushes Using Surface-Initiated ATRP

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. 1H 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 DMAEMA induced stretching of the brushes.