Patterned Nano-micro Hierarchical SERS Flexible Substrate For Detection Of Ultrasensitive TNT

Trinitrotoluene?TNT?explosive is one of the most widely used military explosives.It has a hundred years of production and use history and is widely used in civil,mining and fixed-point blasting.TNT will cause serious pollution to the environment,especially soil and water resources.When people directly or indirectly touch and ingest a small amount of TNT,it will cause import ant harm to life and health.TNT is also an important part of a variety of explosives.At present,the main explosive in our country is still TNT,so detecting the existence of TNT is the main direction of explosive detection.In this paper,a surface-enhanced Raman Spectrum?SERS?technique and the molecular interaction mechanism of Meisenheimer complex?Meisenheimer?are used to design a flexible substrate with a graded micro-nano structure for trace detection of TNT.Oxygen plasma treatment performs surface treatment on polydimethylsiloxane?PDMS?to form periodic nano-wrinkles.Three different patterns and elongation rates are designed to evaluate the generated wrinkle cycle.SERS performance is evaluated using dynamic mechanical analysis and electromagnetic.The simulation validates the experiment theoretically,and at the same time,the substrate is used for laboratory and on-site testing of TNT.The main research contents of this article are as follows:The first part is the preparation of flexible nano-micro hierarchical SERS?NMHS?substrate.Through analysis and research,Auto CAD design and UV lithography machine were used to engrave three micron-level patterns on PDMS.Both the stretching and oxygen plasma treatment were performed on the PDMS surface for silicon oxidation.The stress distribution is different,the nanowrinkles effect produced after releasing the tensile force is different.An electron beam deposition system is used to deposit a certain thickness of gold nanoparticles on PDMS as a reinforced precious m etal material.The second part is the characterization and performance testing of the SERS substrate.By using field emission scanning electron microscopy to characterize the SERS substrate,the formation mechanism was explored.The reporter molecule Rhodamine 6G?R6G?was used to test the performance of the SERS substrate,optimize the experimental data,and evaluate the signal uniformity and substrate repeatability of the SERS substrate under optimal experimental conditions.The third part is the feasibility of the principle of nano-wrinkles on the substrate and the principle of TNT detection.The dynamic mechanical analysis software was used to mechanically analyze the principle of nano-wrinkles of PDMS treated with stretched oxygen plasma.In this paper,the molecular interaction of the Meissenheimer complex and the coupling between silver nanoparticles?Ag NPs?and substrate folds are used to generate huge SERS signals for TNT detection.Using software based on the finite element method to conduct electro magnetic simulation to study the principle of SERS signal enhancement.The fourth part is Conduct laboratory and field-detection.We use the immersion method for laboratory testing of TNT solution,the limit of detection?LOD?can reach 10^-13mol L^-1,and shows good linearity.The on-site detection of TNT trace powder by wiping method,LOD could reach 10^-9mol L^-1,which means that the substrate we prepared has good practical value.