This work focuses on the preparation of gold nanoparticles decorated with well-defined polystyrene (PS) for PS-based thin nanocomposite films. Reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene using dibenzyltrithiocarbonate (DBTTC) as a chain transfer agent (CTA) followed by a hydrolysis reaction produced a thiol end-capped PS. The polymer was successfully used as polymeric surface modifier in a two-phase gold nanoparticle (Au-NP) synthesis process, generating Au-NPs having average diameters ranging from 3 to 5 nm. The Au-NPs were incorporated into PS thin films to fabricate organic memory devices, exhibiting switching behaviors. (C) 2010 Elsevier Ltd. All rights reserved.