Study On The Preparation And Properties Of Low-cost Flexible SERS Substrate

Surface-enhanced Raman scattering technology will encounter problems such as poor sensitivity of the substrate and high preparation cost in the practical application.At present,the preparation of plasma nanostructured substrates with abundant hot spots is one of the main strategies to achieve high detection performance.The template stripping method can prepare certain surface structures on flexible materials to provide abundant hot spots,and has the advantages of simple process and low preparation cost.Therefore,in this thesis,we designed two low-cost flexible SERS substrate with high sensitivity,high reproducibility,high stability and high repeatability,and studied their performance in detail.The specific research content is as follows:（1）A kind of flexible SERS substrate based on inverted pyramid structure was designed and fabricated.The inverted pyramid structure has large surface area,good periodicity,and can attach silver nanoparticles to establish high density enhancement hotspot.Trace determination of carbendazim pesticide was successfully realized with this substrate,and the detection limit was 0.01μg/ml.By establishing a linear relationship between carbendazim concentration and Raman intensity of characteristic peak at 1226cm^-1 and 1270 cm^-1,the determination coefficient was R²=0.9934 and R²=0.99394,respectively.It shows that the substrate has certain ability of quantitative detection.When10 points on the same substrate were sampled,the relative standard deviation RSD of Raman intensity at 1226 cm^-1 characteristic peak was 3.73%,indicating that the substrate had good signal reproducibility.The results of time stability test show that the RSD of intensity variation at 1226 cm^-1 characteristic peak within 9 days are 1.76%,indicating that the substrate has good time stability.The test results show that the substrate has good repeatability under the same condition.（2）A kind of flexible SERS substrate based on nano-cone structure was fabricated.Using inverted conical porous alumina as template,another kind of flexible SERS substrate with stable properties was obtained on the surface of PDMS using template stripping technique.The substrate successfully realized trace detection of carbendazim pesticide and dimethylene pesticide,the detection limits were 0.01μg/ml and 0.01mg/ml,respectively.By establishing a linear relationship between carbendazim concentration and Raman intensity of characteristic peaks at 1226 cm^-1 and 1270 cm^-1,the decision coefficients were,R²=0.98274 and R²=0.99664,indicating that the substrate has a certain ability of quantitative detection.When 10 points on the same substrate are sampled,the relative standard deviation RSD of Raman intensity at the characteristic peak of 1226cm^-1 is 3.6%,indicating that the substrate has good signal reproducibility.The results of time stability test show that the relative standard deviation RSD of Raman intensity at1226 cm^-1 characteristic peak within 9 days is 2.28%,indicating that the substrate has good time stability.The test results show that the substrate has good repeatability under the same condition.