An Antibacterial, Self-adhesive, Recyclable and Tough Conductive Composite Hydrogel for Ultrasensitive Strain Sensing.

Owing to the characteristics of mimicking human skin's function and transmitting sensory signals, electronic skin (e-skin), as an emerging and exciting research field, has inspired tremendous efforts in the biomedical field. However, it is frustrating that most e-skins are prone to bacterial infections, resulting a serious threat to human health. Therefore, the construction of e-skin with integrated perceptual signal and anti-bacterial properties is highly desirable. Herein, the dynamic supramolecular hydrogel was prepared through a freezing/thawing method by crosslinking the conductive graphene (G), biocompatible polyvinyl alcohol (PVA), self-adhesive polydopamine (PDA) and in situ formation antibacterial silver nanoparticles (AgNPs). Having fabricated the hierarchical network structure, the PVA-G-PDA-AgNPs composite hydrogel with tensile strength of 1.174 MPa and elongation of 331% paves a promising prospect for flexible e-skins. Notably, the PVA-G-PDA-AgNPs hydrogel exhibits outstanding antibacterial activity to typical pathogenic microbes (e.g., gram-negative Escherichia Coli and gram-positive Staphylococcus aureus), which effectively prevents bacterial infections that harm to human health. With self-adhesiveness to various surfaces and excellent conductivity, the PVA-G-PDA-AgNPs composite hydrogel was used as strain sensors to detect a variety of macro-scale and micro-scale human motions successfully. Meanwhile, the excellent re-healing property allows the hydrogel to recycle as a new sensor to detect large-scale human activities or tiny movement. Based on these remarkable features, the antibacterial, self-adhesive, recyclable and tough conductive composite hydrogels possess the great promising application in biomedical materials.