Smart Diblock Copolymers as Templates for Magnetic-Core Gold-Shell Nanoparticle Synthesis

We report a now strategy for synthesizing temperature-responsive gamma-Fe2O3-core/Au-shell nanoparticles (Au-mNPs) from diblock copolymer micelles. The amphiphilic diblock copolymer chains were synthesized using reversible addition-Fragmentation chain-transfer (RAFT) with a thermally responsive smart poly(N-isopropylacrylamide) (pNIPAAm) block and an amine-containing poly(N,N-dimethylaminoethylacrylamide) (DMAEAm) block that acted as a reducing agent during gold shell formation. The Au-mNPs reversibly aggregated upon heating the solution above the transition temperature of pNIPAAm, resulting in a red-shifted localized surface plasmon resonance.