Direct Passivation of Hydride-Terminated Silicon (100) Surfaces by Free-Radically Tethered Polymer Brushes

A simple and effective means for passivating crystalline silicon is reported by the use of free-radical polymerization (FRP) to directly graft polymer chains to a hydride-terminated surface (Si−H). Complete surface coverage and passivation was achieved in approximately 24 h at 60 °C or 30 min at 90 °C. Mechanistic studies determined that chain attachment followed a hydride-transfer-based grafting-to mechanism. The grafting process is compatible with a variety of monomers and was used to assemble polymer brush layers (2−12 nm thick), with grafting densities ranging from 0.02 to 0.65 chains/nm2 rivaling densities typically obtained by grafting-from scenarios. This new passivation route provides a uniquely accessible means to covalently anchor dense polymer brushes to silicon surfaces without the need for functionalization of the polymer chain ends or the substrate.