An all-natural strategy for versatile interpenetrating network hydrogels with self-healing, super-adhesion and high sensitivity

Self-healing conductive hydrogels create an important class of smart skin materials with robust mechanical properties and sensitivity. Yet, these reported hydrogels cannot function steadily or be widely used because of expensive cost, complex synthetic process and weak stability. Reported here is a novel interpenetrating network hydrogel based on an all-natural strategy with carboxymethyl cellulose and dopamine as raw materials. The interpenetrating network was constructed via a facile one-step method with amidation reaction and oxidative self-polymerization occurred simultaneously. The impressive features, self-healing performance and mechanism of the hydrogel were explored and unfold. This hydrogel could not only self-heal completely after destruction (3h 98.37%), but also had high sensitive feature (GF=4.741). It could detect various body movements (even throat vocalization and pulse beat) as a sensor in real-time. The excellent self-healing performance was thanked to multiple noncovalent reversible interactions. Both ultraviolet light and high water content contributed to the self-healing process. At the same time, this hydrogel showed super-adhesion (427±4 KPa) to various surfaces, such as human skin, paper, plastic, branch, stone, leaf and so on. And the super-adhesion character enabled the hydrogel to lift up to 10,000 times its own weight. Due to its unique structure, excellent self-healing performance, good tensile and compressive properties, impressive resilience, super-adhesion and high sensitivity, this versatile hydrogel is expected to serve as a novel smart skin system with remarkable intelligent wearable properties.