Study On Preparation And Performance Of Poly (Acrylamide-Co-Acrylic Acid) Ionic Conductive Hydrogel Sensor

Flexible wearable sensors have attracted more and more attention in the fields of electronic skin,soft robots,human-machine interfaces,and health monitoring.Among them,the ion conductive hydrogel sensor has great application due to its flexibility,adjustable conductivity and excellent stretchability similar to human tissue.However,most ion-conducting hydrogels have many problems,such as poor mechanical properties and only responding to a single strain stimulus.In this paper,the double network structure was designed to improve the mechanical performance and sensing properties of poly（acrylamide-acrylic acid）（PMAA）multifunctional hydrogel sensor.The sodium alginate（SA）/PMAA/Ca²⁺conductive hydrogel was prepared,and the effects of sodium alginate content and calcium ion concentration on the mechanical properties,electrical conductivity and sensing properties of the hydrogel were studied.The results showed that with the increase of sodium content,the mechanical properties of SA/PMAA/Ca²⁺hydrogels gradually increased.When calcium ion concentration increased,the mechanical properties and electrical conductivity of SA/PMAA/Ca²⁺hydrogels gradually increased,while the sensing performance gradually decreased.When the SA content and the Ca²⁺concentration was 2 wt%and 0.3 M,respectively,the comprehensive performance of the hydrogel was the best with tensile strength of 410 k Pa,the elongation at break of 2626%,and the maximum sensitivity（GF）of 7.1.The sensor based on SA/PMAA/Ca²⁺conductive hydrogel could monitor human motion detection,touch recognition,temperature detection,sweat detection,p H detection and organic solvent detection.The polyvinyl alcohol（PVA）/PMAA/Fe³⁺conductive hydrogel was synthesized,and the effects of acrylic acid content and iron ion concentration on the mechanical properties,electrical conductivity and sensing properties of the hydrogel were investigate.The results showed that with the increase of acrylic acid content,the mechanical properties of PVA/PMAA/Fe³⁺hydrogel gradually increased;with the increase of iron ion concentration,the mechanical properties of PVA/PMAA/Fe³⁺hydrogel first increased and then decreased,the electrical conductivity gradually increased,while the sensing performance gradually decreased;when the ratio of AAc to AM was 2/10 and Fe³⁺concentration was 0.03 M,the comprehensive performance of the hydrogel was the best,with a tensile strength of 905 k Pa,an elongation at break of 816%,and a maximum sensitivity（GF）of 2.5.The（PVA）/PMAA/Fe³⁺conductive hydrogel had recyclability and biocompatibility.The sensor based on（PVA）/PMAA/Fe³⁺conductive hydrogel could monitor human motion detection,touch recognition,temperature detection,sweat detection,p H detection and organic solvent detection.The PVA/PMAA/Fe³⁺/Gly conductive hydrogel was prepared,and the influence of glycerin content on the mechanical properties,electrical conductivity,sensor performance,freezing resistance and water retention performance of the hydrogel were studied.The results showed that:with the increase of glycerin content,the mechanical properties and electrical conductivity of PVA/PMAA/Fe³⁺/Gly hydrogel gradually decreased,while the sensing performance,antifreeze performance and water retention performance gradually increased.When the glycerin content was 50 wt%,the comprehensive performance of the hydrogel was the best with the tensile strength of 409 k Pa,the elongation at break of 934%,the highest sensitivity（GF）of 3.13,the freezing temperature of-42°C,and the mass retention rate after seven days of 90.3%.The sensor based on PVA/PMAA/Fe³⁺/Gly conductive hydrogel could monitor human motion detection,touch recognition,temperature detection,sweat detection,p H detection and organic solvent detection.