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

• Published in: Langmuir 2009-08, Vol.25 (16), p.9232-9239
• Main Authors: Moran, Isaac W, Carter, Kenneth R
• Format: Article
• Language: English
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Interfaces: Adsorption, Reactions, Films, Forces; Surface physical chemistry
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la900795d

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.