Tunable platforms by coupling gold nanorectangles and pNIPAM for surface-enhanced Raman scattering

Abstract

This paper describes a new plasmonic platform made of lithographic gold nanorectangles array coated by a thermosensitive polymer layer poly(N- isopropylacrylamide). This polymer layer responds to temperature variations by conformational changes and is therefore able to vary the distance between the gold surface and the molecular probes. Hence, this stimulable substrate can be used as a tunable device for surface-enhanced Raman scattering (SERS) using Nile blue A as a molecular probe. We show that an increase of the external temperature reversibly induces a significant enhancement of the Nile blue A SERS signal. This was attributed to a stronger interaction between the gold nanorectangles and Nile blue A. The thermosensitive plasmonic devices developed in this paper thus provide a dynamic SERS platform for sensing application.