Flexible and reusable SERS substrate for rapid conformal detection of residue on irregular surface

Surface-enhanced Raman scattering (SERS) is gaining prominence as a rapid and effective detection method. However, this technique is still challenged by reusability and sampling issues, especially on irregular surfaces. To address these obstacles, a flexible SERS substrate is designed in this study by using reduced graphene oxide (rGO) as the active material and cotton fabric as the substrate material. The cotton fabric is first modified with a silicane coupling agent before coating with rGO to enhance the adhesion between the rGO and cotton fabric, which would allow reusability of the substrate. The resultant SERS substrate shows a better performance with an enhancement factor of 8 × 10³ and a calculated sensitivity of 4.5 × 10⁻⁶ M, as well as excellent signal reproducibility with a relative standard deviation (RSD) of 4.72% and stability with RSD value of 5.47%. Meanwhile, the SERS substrate also demonstrates enhanced reusability, and retains strong Raman signals of the dye molecules even after 40 cycles of detection and washing process. The exceptional SERS performance, enhanced reusability, stability and signal reproducibility, along with other intrinsic advantages, such as low cost, ease of availability, and excellent flexibility, render the obtained SERS substrate in this study a promising product for detection in practical applications.