Ionic conductive amylopectin hydrogels for biocompatible and anti-freezing wearable sensors

Conductive hydrogels with excellent flexibility, durability and functional diversity have great development prospects in the field of flexible strain sensors. However, most hydrogels inevitably lose their properties (such as elasticity, electrical conductivity, fatigue resistance, etc.) when frozen and crystallized in low temperature environments, severely hindering their application in extreme environments. Hence, the hydrogel was successfully prepared by introducing amylopectin, polyvinyl alcohol, lithium chloride and glycerol, which possessed the ability of freezing resistance and water retention. The interaction between amylopectin and polyvinyl alcohol formed hydrogen bonds, which endowed the hydrogel excellent tensile strain (608%) and stress (581 kPa). In addition, the hydrogel possessed significant water retention and excellent freeze resistance due to the introduction of glycerol and lithium chloride. Simultaneously, the PGLA hydrogel was placed into mice for 14 days without redness, swelling, allergy and other reactions, indicating the hydrogel with biocompatibility. More importantly, the PGLA hydrogel could detect not only the large strain caused via joint campaign but also the small strain exhibited by weak mastication. This research provides a new way to the development of wearable sensors with the ability to operate in low-temperature environments and biocompatibility.