Nafion stabilized Ag nanopillar arrays as a flexible SERS substrate for trace chemical detection

In this work, a novel method for fabrication of a flexible SERS substrate was designed and implemented by combining colloidal lithography, oxygen plasma etching, ionic exchange and in-situ chemical reduction on Nafion membrane. First of all the periodic nanopillar arrays were produced on Nafion membrane by colloidal lithography and oxygen plasma etching. Further, ionic exchange and in-situ chemical reduction were carried out through which three-dimensional (3D) Nafion stabilized Ag nanopillar arrays were obtained that showed significant contribution to SERS enhancement. The SERS results showed that the optimized Nafion stabilized Ag nanopillar arrays exhibited high SERS sensitivity to R6G and good reproducibility to p-ATP. The R6G with a low concentration of 10(-11) M could be detected and the good reproducibility with relative standard deviation (RSD) less than 10% could be obtained using a portable Raman spectrometer. After undergoing the cyclic bending deformation, the flexible substrate still maintain stable SERS signals, implying that it can withstand mechanical deformation without losing SERS performance. In addition, the designed platform achieved high sensitivity to detect the harmful malachite green (MG) with a low concentration of 10(-10) M, signifying a pronounced prospect as a potential flexible SERS platform for trace harmful chemical sensing.