A bionic tactile plastic hydrogel-based electronic skin constructed by a nerve-like nanonetwork combining stretchable, compliant, and self-healing properties

Abstract

To completely mimic the tactile sensing of natural skin, flexible conductive hydrogels (CHs) have been assembled into bionic skin. However, most CHs cannot perfectly rebuild the feeling of human skin due to their highly linear structure. In addition, CHs are difficult to meet the super-stretchable, rapid self-healing properties at the same time. Here, we innovatively incorporated a proanthocyanins/reduced graphene oxide (PC/rGO) composite with a nerve-like nanonetwork into a glycerol-plasticized polyvinyl alcohol-borax (PVA-borax) hydrogel system to obtain a bionic tactile PC/rGO/PVA hydrogel-based electronic skin, which perfectly simulates the tactual sensation of human skin and integrates excellent stretchability (>5000%), compliance (1 mm), self-healing (3 s, 95.73%) ability for the first time. Due to its unique structure and mechanical properties, this electronic skin has remarkable wearable and strain-sensitive (GF = 14.14) properties, which can mimic and detect some real skin epidermis movements such as finger bending, facial expression changes, and throat vocalization. Interestingly, the hydrogel can also be used as an adhesive electrode for the accurate detection of electrocardiograph (ECG) and electromyography (EMG) signals. More importantly, this work provides a new route in mimicking the natural skin’s tactile ability through a hierarchical design of hydrogel networks.