Preparation of Nanocomposites by Reversible Addition-Fragmentation Chain Transfer Polymerization from the Surface of Quantum Dots in Miniemulsion

Herein, we report the synthesis of quantum dots (QDs)/polymer nanocomposites by reversible addition-fragmentation chain transfer (RAFT) polymerization in miniemulsions using a grafting from approach. First, the surfaces of CdS and CdSe QDs were functionalized using a chain transfer agent, a trisalkylphosphine oxide incorporating 4-cyano-4-(thiobenzoylsulfanyl)pentanoic acid moieties. Using a free radical initiator (AIBN) to activate the RAFT process, a polystyrene (PS) block was grafted from the surface of the QDs. Quantum confinement effects were identified for the nanocomposite obtained, so attesting to the integrity of the QDs after the polymerization. Free PS chains were also present in the final nanocomposite, indicating that the RAFT polymerization from the surface of the QDs was accompanied by conventional free radical polymerization. After isolating the nanocomposite particles, a second poly(n-butyl acrylate) block was tentatively grown from the initial PS block. The first results indicated a successful polymerization of the second polymer and show the potential of the current strategy to prepare block copolymers from the surface of the RAFT-modified QDs. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5367-5377, 2009