(556c) Low Temperature Growth of Thick Polystyrene Brushes Via Atrp

Atom transfer radical polymerization (ATRP) of styrene has typically been done at temperatures near or above the Tg for polystyrene. Under these conditions, thermal self-polymerization of styrene occurs readily, resulting in consumption of monomer and, in the case of graft polymerization, cessation of layer growth. In this work, we examine the low temperature, surface-confined growth of polystyrene (PS) from a primary polymer layer of poly(glycidyl methacrylate) (PGMA) on silicon using ATRP. The PGMA layer provides a large number of bromoester surface initiator sites compared to self-assembled monolayers and has yielded high graft density PS brushes by ATRP at 130 °C. By lowering the temperature to 60 °C, we were able to grow thick PS brushes with rapid kinetics using the CuBr/PMDETA catalyst system. Furthermore, growth rates were linear, which indicates that growth was controlled, even without addition of Cu(II) or sacrificial initiator.