Poly(ionic liquid)s based Thermal-Responsive Microgel for the Use as SERS Substrates with "ON-OFF" Switchable Effect.

A temperature-responsive surface-enhanced Raman scattering (SERS) substrate with "ON-OFF" switching based on poly(ionic liquid)s (PILs) block copolymer microgels has been designed and synthesized. The PILs units act as a joint component to anchor the gold nanoparticles (AuNPs) and analytes onto poly(N-isopropylacrylamide) (PNIPAm). This anchor allows the analytes to be fixed at the formed hot spots under temperature stimulus. Owing to the regulation of PNIPAm segment, the SERS substrates exhibited excellent thermally responsive SERS activity with reversible "ON-OFF" effect. Additionally, because of the anion-exchange of PILs, microgels can introduce new analytes, which offers more flexibility for the system. The substrate shows excellent reversibility, controllability and flexibility of SERS activity, which is expected to have a broad application in the field of practical SERS sensors. This article is protected by copyright. All rights reserved.