Preparation of PVA/PAM/Ag strain sensor via compound gelation

Polyvinyl alcohol (PVA) and polyacrylamide (PAM) hydrogels as well as silver particles (Ag) composites are prepared by compound gelation. The structure and properties of the composites, which are controlled by the reaction of acrylamide in the hydrogel, are analyzed and the feasibility of their application in strain sensors are explored. The effects of different PVA concentration, content, and particle size of Ag on the mechanical properties, rheological properties of the composites are studied. PVA/PAM/Ag composites are selected as the substrate of the strain sensor, when the concentration of PVA is 0.08 g/ml, the particle size of Ag is 60 nm and the addition amount is 0.15 wt%. The strain sensing performance of the composites under low strain (5%, 20%, and 50%) and high strain (100% and 200%) are tested respectively. The hydrogel composite sensor shows sensitive and stable response to human motion, and it has the ability of distinguish the movement of different human body joints.