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′-(α, α′-dimethyl-α″-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.

► Novel Fe3O4@PNIPAM@Au nanocomposites were synthesized.
► The nanocomposites inherit superparamagnetism and surface plasmon resonance.
► Surface plasmon resonance is thermo-responsive.