Preparation And Performance Study Of Flexible Pressure Sensors Based On Different Substrates

Centered on the printing of flexible pressure sensors,in this theses,two different materials,PDMS silicone rubber and polyphenoxy resin,were selected as doping substrates for flexible composite functional materials and carbon black nanoparticles as conductive doping fillers to prepare two sets of flexible pressure sensors with different principles in a printed manner.And by determining the conductivity threshold,adding silica nano-doping,and curing agent cross-linking modification,the performance and preparation process were improved and enhanced respectively,and the influence of each factor such as material formulation,solid content,three-roll grinding,and curing additives on the sensor preparation was investigated.The pressure sensor inks were first prepared using different types of PDMS silicone rubber to compare better functional sensor ink formulations.Two different types of sensors with "forked finger" structure and "sandwich" structure were prepared by screen printing and ink scraping respectively.Based on the conductivity threshold theory and the mass percentage concentration of carbon black as a reference,the conductivity percolation threshold interval of different formulations was determined by comparing the conductivity of different solid content material systems,and the optimal ratio of conductive carbon black in the formulations was determined.Based on this,fumed silica nanoparticle additives were added to the composite system to obtain a flexible pressure sensor with better performance.Finally,different formulations and different types of flexible pressure sensors were tested to compare the piezoresistive properties,creep properties and cyclic stability of each sensor,and the ink formulation and process of flexible pressure sensors with obvious piezoresistive effect,good linear relationship,small creep and good cyclic stability were investigated,which have a wide range of application prospects.In addition,the curing mechanism of the sensor functional material was investigated by using polyphenoxy resin as a doped substrate,and the structure of the substrate material was changed by adding anhydride curing agent to prepare a sensing material with good resistance to creep and temperature resistance,and the structure and printing process of the flexible pressure sensor were designed based on the principle of interface effect.The structural changes were verified by infrared characterization and cross-linking curing tests on the composite material;the piezoresistive characteristics,resistance creep,and temperature resistance of the flexible pressure sensor were tested,and the results showed that the flexible pressure sensor has a resistance creep rate of 14%when the acid anhydride equivalent ratio r = 0.16,and can withstand a maximum temperature of 110°C.It has great development prospects and application markets in the future.