Enhancement of SERS performance using hydrophobic or superhydrophobic cotton fabrics

Because the hydrophobic surface can reduce the diffusion of probe molecules and enrich the detection materials effectively, two types of hydrophobic Surface-enhanced Raman spectroscopy (SERS) substrates were prepared in this work. Cotton fabrics were used as raw material, employing printing and spraying methods to fabricate substrates with various levels of hydrophobicity. A silver layer was deposited on the surface of the hydrophobic substrates by vacuum evaporation to prepare hydrophobic and super-hydrophobic SERS substrates, and p-aminothiophenol (PATP) was used as probe molecule to explore SERS performance of different samples. The analyzed results show that the enhancement factor of the optimized hydrophobic SERS substrate is 1.57 × 106, and the detection sensitivity can reach up to 10−10 M and the relative standard deviation (RSD) value is 11.19%. The enhancement factor of the optimized super-hydrophobic SERS substrate is 1.93 × 106, its detection limit is low to 10−11 M, RSD value is 8.11%, and it still has the effect of enhancing Raman signal after 6 months of storage. The detection limit of the optimized super-hydrophobic substrate for lead ion solution is as low as 200 nM. Compared with hydrophilic substrates, the SERS performances of the substrates with hydrophobic surface are improved significantly.