Understanding the morphologies and polymerization mechanism of homopolymer and block copolymer brushes by living anionic surface initiated polymerization

Homopolymer and block copolymer brushes grafted from Au and Si (SiOx) surfaces via living anionic surface initiated polymerization (LASIP) has been reported. 1,1-diphenylethylene (DPE) derivative, an initiator for anionic polymerization, was grafted onto planar Si-wafer and Au surfaces by self-assembled monolayer (SAM) techniques. n-BuLi was used to activate the DPE for anionic polymerization of monomers at the interface under high vacuum. By a careful sequence of monomer introduction, reaction, and termination, homopolymer and block copolymer tethered polymer brushes were obtained. The importance of initiator activation, control of polymerization conditions, and removal of excess BuLi is emphasized. Interesting differences in morphology, thickness, grafting density, and polymerization conditions contrasts LASIP from solution and other surface initiated polymerization (SIP) mechanisms. The formation of block copolymer sequences highlights the unique utility of a living anionic polymerization technique on surfaces.