Environmentally Responsive Surface-Enhanced Raman Scattering Substrates for High Sensitivity

摘要

Surface-enhanced Raman scattering (SERS) has been of growing interest as a powerful tool to study vibrational information of molecules adsorbed on metallic nanoparticles (MNPs). Recently, environmentally responsive SERS substrates composed of a variety of inorganic-organic composites have been developed for highly sensitive chemical detection because of enhanced electromagnetic plasmonic coupling which occurs by different external stimuli. Specifically, hybrid plasmonic nanostructures composed of MNPs and thermoresponsive poly(N-isopropylacrylamide) (p(MPAM)) brushes grown on gold substrates were prepared by surface-initiated atom-transfer radical polymerization of NIPAM, followed by immobilization of gold NPs exclusively at the end of p(NIPAM) chains via covalent bonding or non-covalent interaction, which are capable of thermally-induced electromagnetic coupling as advanced SERS substrates. However, there have been obstacles to strong ionic interaction between gold NPs and entire p(NIPAM) chains for ultrasensitive detection.