Poly(vinyl alcohol)/Gelatin-Based Eutectogels for the Sensitive Strain Sensor with Recyclability and Multienvironmental Suitability

Flexible gel-based strain sensors have made remarkable progress, emerging as promising candidates for wearable electronic devices. Too much attention was paid to the sensing sensitivity of the conventional gel sensors, and their environmental tolerance and green recyclability were ignored. This work designs a high ion conductive, multienvironmentally adaptable, and recyclable eutectogel, with gelatin-strengthened poly(vinyl alcohol) (PVA) and deep eutectic solvent (DES) as the gelator and disperser, respectively. Interestingly, the cross-linked network composed of PVA and gelatin polymer molecules endows the eutectogel with an ultimate tensile strength of 6.8 MPa. Moreover, the ionic liquid-like characteristic of DES at room temperature and abundant hydrogen bonds in DES can simultaneously improve the ionic conductivity (0.12 S/m) and environmental tolerance of the eutectogel. A reliable strain sensor based on this eutectogel exhibits high stability over a wide temperature range (−20∼100 °C) and harsh chemical environments (acid and base). Furthermore, this recyclable eutectogel can be easily disintegrated and regelatinized via a simple solvation–evaporation procedure, while retaining its initial mechanical and sensing performances. This study creates a candidate for applications in wearable electronic devices and sheds light on minimizing the environmental impact of other electronic wastes.