2,2,6,6-Tetramethylpiperidine-1-oxy-Oxidized CelluloseNanofiber-Based Nanocomposite Papers for Facile In Situ Surface-EnhancedRaman Scattering Detection

In this study, we report a flexible transparent free-standing surface enhanced Raman scattering (SERS) platform composed of 2,2,6,6-tetramethylpiperidine-1-oxy-oxidized cellulose nanofibers (TEMPO-CNF) and gold nanoparticles (AuNP) such as nanospheres (AuNS) and nanorods (AuNR) for in situ chemical sensing of a real-world surface. The TEMPO-CNF/AuNP-based nanocomposites were fabricated using two-step filtration with pure TEMPO-CNF solution and TEMPO-CNF/AuNP mixture solution. We demonstrate that the TEMPO-CNF/AuNR nanocomposite reveals better SERS activity than the TEMPO-CNF/AuNS nanocomposite. The TEMPO-CNF/AuNR nanocomposite detected rhodamine 6G down to 10 nM with a high enhancement factor of 2.1 × 107 and exhibited good SERS measurement reproducibility in the flexible/bent state. No significant change in SERS intensity was observed even after 1000 cycles of bending to nearly 90 degrees. Importantly, the flexible transparent TEMPO-CNF matrix allows the TEMPO-CNF/AuNR nanocomposite to be tightly wrapped...