Preparation And Properties Of Gel-based Strain Sensing Material

As a carrier for receiving and transmitting signals,sensors are indispensable in the R&D and manufacturing of smart devices.Ordinary sensors have problems in such as poor flexibility,durability,poor portability,and high cost.Therefore,it is particularly important to develop a stretchable,highly flexible,durable and low-cost sensor.Aiming at the above problems,this paper uses conductive hydrogel as the substrate to study the structure and performance of three conductive gel materials that can be used for strain sensors.The general contents are as follows:(1)Polyvinyl alcohol(PVA)/polyacrylamide(PAM)/silver particles(Ag)composite conductive hydrogels were prepared by high-temperature rapid polymerization.Through comparative analysis of different PVA concentration,different content and particle size of Ag,the mechanical properties,rheological properties,water content and swelling properties of the composite hydrogel were explorered.The hydrogel sensor prepared on the basis of this material exhibits strain sensing stability and repeatability in a wide range of 5% to 200%.(2)The dimethyl sulfoxide(DMSO)-N,N-dimethylformamide(DMF)binary mixed solvent with well-dispersed multi-walled carbon nanotubes(MWCNTs)was obtained by the method of ultrasound and then centrifugation.The effects of PVA mass fraction,different types and mass fractions of MWCNTs on the structure and performance of composite hydrogels were studied.Combining the results of mechanical properties,rheological properties,water content and swelling properties,the optimal formula for preparing PVA/MWCNTs composite conductive hydrogel is obtained.The strain sensor prepared on the basis of this composite hydrogel has good stability and repeatability,as well as the ability to distinguish different joint motions.(3)Focusing on the structure and properties of the PVA/PAM/Ag composite gel,the process parameters of AM in DMSO photoinitiated polymerization and the influence of the presence of PVA and Ag on the mechanical and electrical properties of PAM organogel were studied.The gel has good moisture retention.Compared with PAM gel,the strength and elastic modulus of PVA/PAM/Ag composite gel are increased by nearly 10 times.The strain sensor made by this gel shows excellent and stable strain sensing performance at a low strain of 5% to 50%,and the sensing performance fluctuates at a large strain of 100%.