An environment-stable and tough wearable sensor enabled by xanthan gum-assisted hydrogel

Wearable sensors based on ionic hydrogels have attracted increasing attention, but practical application is often hampered by poor environmental tolerance. Here, an environment-stable and tough hydrogel was constructed by introducing glycerin, sodium chloride and xanthan gum into a polyvinyl alcohol hydrogel network. Hydrogen bonds were formed among glycerin, xanthan gum and polyvinyl alcohol chains to enhance the toughness of hydrogel. Furthermore, the salting-out effect of polyvinyl alcohol chains induced by sodium chloride also improved the strength of hydrogel. Besides, the hydrogel was highly sensitive to mechanical deformation of tensile and compressive strain. The obtained hydrogel with sensitivity was capable of serving as a wearable sensor for monitoring human motions including speaking, bending articulation and so on. Notably, the hydrogel still maintained flexibility, toughness and conductivity under subzero or ambient conditions for a long time. This simple method paves an effective way for designing environment-stable and tough hydrogels.