Flexible SERS substrate based on Ag nanodendrite–coated carbon fiber cloth: simultaneous detection for multiple pesticides in liquid droplet

We report a method for preparing flexible substrates based on 3D Ag nanodendrites (Ag NDs)/carbon fiber cloth substrate with superhydrophobic surface. Ag NDs were deposited on carbon fiber cloth by electrochemical deposition, and the superhydrophobicity of the surface was achieved by low surface energy modification. The cylinder shape of the carbon fiber provides a three-dimensional structure for Ag NDs, increasing the “hot spot” effect, and is the excellent choice as SERS substrate. At the same time, micro/nanostructures provided by fibers and nanodendrites can easily obtain ultra-wet surfaces. The analyte solution can be directly detected in a droplet onto the superhydrophobic surface without pretreatment, which greatly shortens the detection time. The lowest concentration of crystal violet (CV) that can be detected is 10⁻¹⁰ M, demonstrating good SERS sensitivity of the prepared substrate. It was successfully applied in simultaneous detection of at least three molecules. Thiram and malachite green (MG) can be detected simultaneously in real lake water. Moreover, the conductivity, physical flexibility, and stability of the flexible carbon fiber cloth gives this substrate potential in other fields such as electrochemistry.