Super tough, stretchable and transparent ionic conductive hydrogel for flexible sensor with excellent temperature tolerance

The construction of high performance ionic conductive hydrogel together with strength, toughness, trans-parency, environment tolerance, stable conductivity and response is still an urgent demand in flexible sensing field. Here, a simple and feasible strategy was proposed to produce ionic conductive hydrogels by integrating polyvinyl alcohol (PVA)/silk sericin (SS) with sodium citrate (Na3Cit) in glycerol (Gl)/water solution. The synergistic action of physical cross-linked polymer networks and supra-molecular interactions enabled the resultant PVA/SS/Na3Cit/Gl hydrogels with super strong (7.56 MPa), tough (39.37 MJ/M3), stretchable (787.96%) and transparent (90%). Especially, the PVA/SS/Na3Cit/Gl hydrogels displayed excellent extreme temperature tolerance, retaining highly stretchability (> 500% strain), strong (7-12 MPa) and tough (25-52 MJ/ M3) at-25 to 60 degrees C or 7 d storage at 30 degrees C. Profiting from these advantageous performances, PVA/SS/Na3Cit/Gl hydrogels could be assembled as transparent flexible sensors to quickly and precisely response human activities with a wide strain range (up to 200% strain), excellent stability and repeatability even at-25 degrees C or 7 d storage. In addition, PVA/SS/Na3Cit/Gl hydrogels showed cytocompatibility with good cell proliferation of Cos 7 fi-broblasts within 72 h incubation. Thus, the presented PVA/SS/Na3Cit/Gl hydrogels suggested a promising prospect as reliable wearable electronics adapting to mechanical and environmental durability.