Effect of rate retardation in RAFT grafting polymerization from silicon wafer surface

Polystyrene and poly(butyl acrylate) were grafted from silicon wafer surface by reversible addition‐fragmentation chain transfer (RAFT) polymerization. Three RAFT agents were immobilized onto silicon wafer through their leaving/initiating groups (R group). Grafting polymerization of butyl acrylate (BA) and styrene (St) was then carried out from the immobilized RAFT agents. The immobilization of the RAFT agents and the subsequent grafting polymerization of St and BA were evaluated by ellipsometry and X‐ray photoelectron spectroscopy. It was found that type of monomer, structure of RAFT agent, and local RAFT concentration on the surface have dramatic influences on the thickness of grafted polymer layer. The grafting polymerization with more severe rate retardation effect yielded thinner polymer films on the silicon wafer. Selection of a RAFT agent with little rate retardation was critical in the grafting polymerization to achieve thick films.