Anti-dryable, anti-freezable, and self-healable conductive hydrogel for adhesive electrodes

Poly(vinyl alcohol) (PVA)-based hydrogels are widely used in devices requiring self-healing abilities. However, these hydrogels consist largely of water; thus, moisture evaporates easily, and the hydrogels cannot be used for a long time. In this study, glycerol (Gly) and 1,2,3,4-butane tetracarboxylic acid were added to a PVA-based hydrogel to enhance its anti-freezing and anti-drying properties. Graphite was then added to provide conductivity. The prepared conductive hydrogel exhibited an excellent self-healing ability in terms of mechanical and electrical performance. With the introduction of Gly, the adhesion of the hydrogel can be easily achieved, and a simple circuit configuration can be used as an adhesive electrode. The manufactured hydrogel has an excellent self-healing ability and conductivity, as well as excellent mechanical/electrical, anti-drying, and anti-freezing properties, making it suitable for the fabrication of next-generation sensors and wearable electronic devices.