Fabrication Of Superhydrophobic Hybrid Nanotip And Nanopore Arrays And SERS Detection

Surface-enhanced Raman Scattering(SERS)is a highly sensitive spectroscopy technique that enables non-destructive testing of analytes.It has broad application prospects in biosensing,medical diagnostics and chemical analysis.The key to achieve SERS quantitative analysis is to fabricate nanostructures that can effectively enhance the strength of local electromagnetic fields through low-cost processing technology,thereby achieving the uniformity and stability of Raman signals.However,how to realize the rapid and effective adsorption of analytes to further increase the detection limit of SERS is an urgent problem to be solved.The droplet on the surface of the superhydrophobic structure shows an almost ideal spherical shape,and the concentration effects can improve the detection sensitivity.Today,the research on super-hydrophobic structure is mainly based on the natural structures.Due to the differences in individuals,it is difficult to apply these plant surfaces as substrates to practical applications.How to simply and rapidly fabricate a highly sensitive artificial superhydrophobic structural substrate still is a challenge.Based on this,we utilized a one-step voltage-variation anodization method to prepare a large area of hybrid nanotip and nanopore arrays(NPNTAs)in a simple and rapid process.After the deposition of silver nanoparticles on the surface,the Raman signal of R6G molecules was detected.The SERS signal has good homogeneity and stability.Subsequently,the surface of the substrate was hydrophobized to further increase the detection limit of the analytes.This article focuses on how to rapidly prepare a Raman substrate with a large area and high detection sensitivity through a simple process,which enables efficient analysis of the analytes.It mainly includes the following two parts:1.Preparation of Porous Anodic Alumina Structure and Detection of SERS Performance.Alumina foil as a substrate was used to prepare hybrid nanotip and nanopore arrays with different structures by one-step voltage-variation anodization method.Silver nanoparticles were deposited on the surface of the structure and R6G was used as a probe molecule to detect Raman signals.The preparation conditions for the best Raman performance substrate were obtained:the oxidation time was 1560 s,and the silver nanoparticle deposition time was 400 s.The Raman signal of different batches of the same structured substrate is at 1650 cm-1 with a relative standard deviation of less than 12%.This shows that the Raman signal of the substrate is uniform.In addition,the optical properties of the substrate were studied.The results show that the substrate has good broadband anti-reflection performance.2.Hydrophobic modification of the substrate for the optimal Raman properties.The influence of the order of deposition of fluorosilane(FS)and silver nanoparticles on the Raman properties of the substrate was investigated.The static contact angle between the substrate surface and the water droplets also was detected.The experimental results show that the surface of NPNTAs modified by FS exhibits superhydrophobic properties.The FS-Ag substrate has optimal Raman properties and can detect 10-8 M R6G solutions.The superhydrophobic hybrid nanotip and nanopore arrays nanostructure substrate designed in this paper can help to create a practical and highly sensitive SERS substrate,laying the foundation for the development of advanced biological and chemical sensors.