Fabrication And Electromechanics Study Of Nanoparticle-polymer Films

The nanoparticle-polymer film material formed by dispersing metal particles in a polymer matrix can have characteristics such as low density,high elasticity,and high conductivity.In recent years,due to the development of emerging technologies and traditional industries,the development of nanocomposites with high elasticity and high conductivity has made it impossible for flexible electronic/optoelectronic products such as wearable devices,smart electronic products,and stress-strain sensors.At this stage,the preparation method of the elastic nanocomposite film material and its electromechanical performance have not been systematically studied in China.In this paper,two types of nano-composite films,AgNPs/PI and AgNPs/PE,were successfully prepared by silver mirror synthesis using polyimide(PI)and polyethylene(PI)substrates.The electrical percolation properties,mechanical properties under large deformation and electro-mechanical piezoresistive properties of nanoparticle-polymer films were investigated.The relationship between "preparation process-structural characteristics-material properties" of composite film materials was explored.In addition,the conductive percolation behavior of the material was simulated by establishing a conductive percolation model,and compared with the experimental results to reveal the physical mechanism observed in the experiment,The paper concluded as follows:(1)In the preparation process of nano-silver particle-polymer film,the particle coverage and particle size of the polymer surface increase with the increase of adsorption time,however the distribution uniformity of nanoparticles decreases with time.(2)Comparing the Monte Carlo simulated conductive percolation results with the experimental data,the two agree that when the particle content is as small as a critical value,the resistance of the two composite film materials AgNPs/PI and AgNPs/PE increases.Two orders of magnitude;when the content of silver particles is further increased,the resistance value does not produce an order of magnitude change,and basically tends to be stable.(3)The addition of nanoparticles enhances the elastic modulus,yield strength and fracture strength of the polymer matrix,but the strain at break decreases.The yield strength and fracture strength of PE matrix materials are slightly higher than those of PI matrix materials.(4)The nanoparticle-polymer film is an anisotropic material.During the uniaxial stretching of the sample,the spacing between the nanoparticles increases,and the longitudinal resistance and lateral resistance of the composite film material increase,but due to the Poisson's ratio effect and each According to the principle of the opposite sex,the lateral resistance increase of the material is always higher than the increase of the longitudinal resistance.(5)In the process of increasing strain,the resistance sensitivity of the two nanoparticle-polymer films is increasing;and the lower the content of silver particles,the higher the resistance sensitivity of such materials.In addition,during the continuous stretching process of the sample,as the number of cycles increases,the sensitivity of the composite film increases and the stability decreases.