A self-adhesive strain sensor based on the synergy of metal complexation and chemical cross-linking

As a promising functional material , hydrogels have received extensive attention in the field of flexible wearable sensors . However, it remains a huge challenge to explore a multifunctional hydrogel sensor combining excellent self-adhesion, strain sensitivity, mechanical attributes, and self-healable ability. Here, different from the traditional dissolution method with strong acidic media, chitosan (CS) was directly dissolved in 2-acrylamide-2-methylpropane sulfonic acid (AMPS) and ferric solution, and then combining acrylic acid (AA) to construct a multifunctional hydrogel based on the synergy of metal complexation and chemical cross-linking. The hydrogels exhibited excellent adhesion both in air and underwater, proper mechanical attributes and self-healable properties. Moreover, the hydrogel with good electrical conductivity possessed strain sensitivity, which could serve as strain sensors to detect body movements. Therefore, this work could broaden sight into the preparation of multifunctional hydrogel strain sensors.