Synthesis and characterization of thermo-sensitive magnetite-Au nanocomposites

Fe3O4@PNIPAM@Au nanocomposites were synthesized via a sequence of reactions including thermal decomposition for iron-oxide synthesis, surface modification by dopamine and a chain transfer agent S-1-dodecyl-S'-(alpha,alpha'-dimethyl-alpha ''-acetic acid)trithiocarbonate, surface-initiated Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAM), reduction of RAFT reagent, and S-Au interaction. Superparamagnetism and surface plasmon resonance (SPR) phenomenon of the nanocomposites were investigated by vibrating sample magnetometry (VSM) and UV-vis spectra. The UV-vis spectra at different ambient temperatures implied the thermo-responsivity of the nanocomposites. The surface of Au can be further functionalized when needed. Such nanocomposites inherit superparamagnetism of Fe3O4, thermo-responsivity of PNIPAM, and SPR of Au nanoparticles, and could have potential applications in biomedical, optical, analytical, and catalytic fields. (C) 2012 Elsevier BM. All rights reserved.