Reduced graphene oxide reinforced PDA-Gly-PVA composite hydrogel as strain sensors for monitoring human motion

Hydrogels with soft, skin-friendly properties and high biocompatibility are promising alternatives to traditional sensors. However, balancing electrical conductivity and sensitivity remains a significant challenge. The sensitivity-improved strain sensor was designed by reduced graphene oxide (rGO) reinforced polydopamine (PDA)-glycerol (Gly)-polyvinyl alcohol composite hydrogels (PGPHs). The hydrogels exhibited excellent sensing sensitivity with a gauge factor of 2.78, conductivity of 2.2 S/m, tensile deformation of 200%, fast response time of 370 ms, and recovery time of 260 ms, surpassing those of most previously reported hydrogel-based strain sensors. This improvement can be attributed to the high electrical conductivity and uniform distribution of the rGO associated with Gly and PDA. PGPHs also exhibited an attractive monitoring effect for hand movements and precise detection feedback for the slight dynamics of the pharynx. Hydrogel-based strain sensors have been demonstrated as a potentially sustainable solution for dynamic detection and communication.