Flexible and recyclable SERS substrate fabricated by decorated TiO₂ film with Ag NPs on the cotton fabric

Flexible and recyclable surface-enhanced Raman scattering (SERS) substrate was fabricated based on woven cotton fabric by grafting Ag nanoparticle on the TiO₂ film which was deposited on the cotton fabric. Due to the synergetic effect of heterostructure Ag/TiO₂ and superior adsorption capacity of fabrics, recyclable SERS cotton fabric (RSCF) possessed excellent SERS sensitivity with a detected concentration of p-Aminothiophenol as low as 10⁻¹² M. Furthermore, SERS performance of RSCF can be recovered after 180 min in the presence of UV light illumination, resulting from the photocatalytic property of TiO₂ on the surface of RSCF. It can be further utilized to reproduce SERS performance of the RSCF through the UV-assisted cleaning. As a trial for potential application, based on the flexibility of cotton fabric, RSCF was employed to detect a pesticide (carbaryl) on the surface of a pear by simply swabbing and low concentration down to 10⁻⁴ M was reached. This work provides a potential guide towards the universal design of the flexible and recyclable SERS substrates for a promising application in the SERS rapid detection of trace-level toxic pollutants on the food.