Fully Stretchable and Self-Healing Graphene-Hydrogel E-Skin with Temperature-Strain Self-Calibration

Hydrogels exhibit mechanical properties very similar to biological skin, rendering them promising candidates for electronic skin (e-skin) sensors. However, these materials suffer from significant temperature-induced electrical drift and unstable interfacial contact with metallic electrodes. In this study, we employ elastic graphene foam as electrodes to realize a fully flexible hydrogel device architecture. By designing straight-line and serpentine hydrogel geometries, we enable temperature self-calibration during strain measurements. The resulting hydrogel sensor demonstrates exceptional performance, including constant strain sensitivity (GF = 2.44 with linearity R2 = 0.9999), rapid strain dynamic response (70 ms), low strain detection limit (0.05%), and low temperature drift. This approach not only addresses critical limitations in hydrogel-based sensing platforms but also establishes a robust framework for developing more reliable and versatile flexible sensors.