Biocompatible and self-healing ionic gel skin as shape-adaptable and skin-adhering sensor of human motions

Artificial electric skin, which is capable of strongly adhering to different parts of human bodies and precisely detect different types of human motions, shows great promise for biomedical prosthetics, human/machine interfaces, wearable devices and soft robotics. In this study, biocompatible ionic gels with shape-adaptability and skin-adhering are produced through in situ polymerizing (3-acrylamidophenyl) boronic acid and acrylamide in the presence of chitosan containing catechol groups. The chemical cross-linkers are capable of modulating their elasticity, toughness and stretching tolerance. The reversible cross-linkers of H-bonding and dynamic covalent bonds endow the gels not only with strong adhering strength on different surfaces (including skin) and rapid self-healing in minutes, but also with large stretchability (e.g., 12–200 times of tensile length) and plasticity for shape-adaptability on irregular surfaces. Thus, by introducing mussel-inspired catechol groups into biomass-based macromolecules, a novel type of artificial ionic skin is designed with high sensitivity in combination with mechanical stretchability and bio-compatibility. They will promise great potential as (but not limited to) the skin-friendly sensor to detect various human motions with high accuracy and repeatability.