Property Research Of Strain Sensing Based On Ag@CNTs And PDMS

With the development of modern electronic products in flexibility,integration and miniaturization,people's demand for intelligent sensors continues to increase.Flexible stress sensors for sensing the distribution of surface forces have become research hotspots,and nanoparticle/polymer composite structures to the sensitivity of stress and strain on mechanical structures has attracted the attention of many scholars at home and abroad.In this paper,we present a highly sensitive and stretchable flexible stress sensing film.In this paper,Ag@CNTs composite nanomaterials were prepared by chemical reduction method.Through the preparation of Ag@CNTs composite nanomaterials with different concentrations of silver nitrate solution,the mechanism of composite nanomaterials was researched.The microstructure,crystal structure and elemental composition of the synthesized materials were characterized by SEM,EDS and TEM.At the same time,two sets of flexible stress films composed of PDMS and Ag@CNTs were prepared by template method.Experimental results show:(1)Ag@CNTs nanostructures were synthesized by the reduction method.The characterization results showed that the Ag NPs in the prepared Ag@CNTs were evenly coated on the surface of CNTs,and the crystal structures were uniform.The experimental results of different reaction conditions show that the Ag@CNTs 1 nanomaterials which the concentration of the silver nitrate solution is 0.03 moL/L coating effect and the dispersion effect are better than that of the Ag@CNTs 2 prepared by the 0.06 moL/L silver nitrate solution.(2)Two sets of flexible stress films composed of PDMS and Ag@CNTs were prepared by template method.Then I-V and tensile tests were performed on both groups of films.By comparison,the flexible film 1 prepared based on Ag@CNTs1 has a larger resistance value than the flexible film 2 based on Ag@CNTs 2,and the maximum stretching range is 9.7%.Introducing a specification factor GF of the flexible sensing film,which can be used to study the sensitivity of the sensor.(3)Through the pre-stretching process to improve the stretchable range of the film,and then through the surface treatment process to improve the adhesion between the PDMS substrate and Ag@CNTs composite nanomaterials to improve the stability and piezoresistive effect of the flexible film.Finally,by studying the effect of different process conditions on the preparation of flexible films,a flexible stress sensing film with surface treatment and wrinkle structure was prepared.The strain range was 0-42.2% and the highest sensitivity factor was 412.At the same time,the conductive mechanism of Ag@CNTs composite nanomaterials is researched in this paper.The sensing mechanism of flexible thin films is also discussed,and the process of thin film fabrication is improved to improve the tensile range and sensitivity of the sensing films.The conclusion is to improve the sensing sensitivity of flexible films and apply the films to human expression test.