Synthesis of Well‐Defined Polymer Brushes from Silicon Wafers via Surface‐Initiated seATRP

ynthesis of densely grafted (co)polymer brushes, including poly(n-butyl acrylate), poly(2-dimethylaminoethyl methacrylate), poly(n-butyl acrylate)-block-poly(tert-butyl acrylate), and poly(2-dimethylaminoethyl methacrylate)-block-poly(tert-butyl acrylate) from silicon wafer surfaces via a simplified surface-initiated electrochemically mediated atom transfer radical polymerization under constant potential/current conditions is reported. A sacrificial (nontethered) initiator is added to form free polymer chains in solution used to estimate the molecular weights and molecular weight distributions of chains attached to the surface. The polymers show narrow molecular weight distributions (Đ = 1.10–1.33). Water contact angle measurements and ellipsometry are used to characterize wettability and thicknesses of the modified surfaces. Grafting densities up to 0.93 nm−2 are obtained. The rate of the polymerization is controlled by applying more negative potential values, which results in an increase in the surface thickness (up to 116 nm). Finally, the poly(tert-butyl acrylate) blocks are hydrolyzed to the poly(acrylic acid) blocks. These new, densely grafted brushes are promising candidates for applications in microelectronics, nanotechnology, tailoring of surface properties, nanopatterning, or antifouling coatings.