Supramolecular Zwitterionic Network Enabling Environment-Tolerant, Transparent, Adhesive, and Biocompatible Organogel for Epidermal Electronics

Ionic hydrogels are ideal for soft bioelectronics due to their softness, stretchability, and ion-mediated signal transduction. However, traditional hydrogels face dehydration and freezing issues. Inspired by natural skin, this study creates a supramolecular ionic organogel using silk fibroin, zwitterionic polymers, Ca2+, and ethylene glycol (EG). The organogel is conductive, highly stretchable, adhesive, environmentally stable, and biocompatible. Theoretical calculations reveal that interactions among Ca2+, zwitterionic groups, EG, and water are stronger than water-water interactions, converting "free" water into "locked" water. This mechanism allows the organogel to retain over 90% of its weight after 30 days at 25 °C and 60% relative humidity, while also resisting freezing by disrupting ice formation. Its conductivity, adhesion, and biocompatibility enable applications in on-skin strain sensors and electrodes for monitoring motion and recording electrophysiological signals. This work elucidates molecular interactions in organogel networks, provides a design framework for environmentally tolerant organogel, and advances ion-conductive bioelectronics.