Shih-Chen Shi, Si-Chi Chen, Dieter Rahmadiawan
Surface-enhanced Raman scattering (SERS) is a highly sensitive analytical technique for detecting trace contaminants such as pesticides and microplastics. Chitosan–copper (Cu) nanocomposites offer a sustainable platform for SERS due to their biocompatibility, antioxidant properties, and plasmonic activity. In this study, a one-step green synthesis approach was developed to fabricate flexible SERS substrates by utilizing chitosan as a natural reductant and stabilizer to convert Cu2+ into face-centered cubic (FCC) Cu nanoparticles (NPs). Here, the term ‘one-step’ specifically refers to the simultaneous chemical reduction and stabilization of Cu nanoparticles within the chitosan matrix. Ascorbic acid was added to accelerate reduction, and glycerin was incorporated as a plasticizer to enhance film-forming ability and flexibility. The resulting Cu–chitosan–glycerin films were evaluated using crystal violet, methomyl, and poly(methyl methacrylate) (PMMA) microparticles. SERS detection limits as low as 1 ppb were achieved for all analytes. A strong correlation was observed between the enhancement factor (EF) and A0.2 values, confirming that uniform Cu NP dispersion enhances electromagnetic hot spot formation. The film containing 2 wt% chitosan and 3 wt% glycerin exhibited the highest EF, attributed to its uniform particle distribution. This work demonstrates a cost-effective and scalable strategy for fabricating eco-friendly SERS substrates with high sensitivity and reproducibility for practical environmental monitoring. © 2026 Elsevier B.V.
Department of Mechanical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan; Department of Mechanical Engineering, Universitas Negeri Padang, Sumatera Barat, Padang, 25173, Indonesia
