Designing and fabricating composites of PNIPAM@Au nanorods with tunable plasmon coupling for highly sensitive SERS detection

In this study, hybrid substrates composed of poly(N-isopropylacrylamide) hydrogels and Au nanorods (PNIPAM@AuNRs) that exhibit tunable plasmon coupling are designed and fabricated. In this process, Au NRs are deposited on the surface of a PNIPAM hydrogel, and the temperature is increased, causing the hydrogel template to shrink, thereby driving the Au NRs closer to each other. The resulting surface plasmon resonances (SPR) of the composite are observed as a large red-shift. The formation of more hot spots increases the already high sensitivity of surface-enhanced Raman scattering (SERS) detection, and the tunable optical properties enable closer matching of the laser to the near-infrared excitation required. Moreover, these hybrid substrates can be conveniently identified by optical microscopy, enabling in situ SERS detection with high sensitivity and reproducibility. (C) 2015 Elsevier Ltd. All rights reserved.