3D Printable Organohydrogel\nwith Long-Lasting Moisture\nand Extreme-Temperature Tolerance for Flexible Electronics

Abstract

Hydrogels with high electrical conductivity and mechanical\nstretchability\nare promising materials for flexible electronics. However, traditional\nhydrogels are applied in short-term usage at room temperature or low\ntemperature due to their poor water-retention ability and freezing-tolerance\nproperty. Here, a dually cross-linked glycerol–organohydrogel\n(GL–organohydrogel) based on GL and acrylic acid was synthesized\nin a GL–water binary solvent. Fe³⁺ ions working\nas an electrolyte were added to improve the conductivity of the organohydrogel\nand form coordination interactions between Fe³⁺ ions and\ncarboxyl groups of acrylic acid. The strong hydrogen bonding between\nGL and water molecules firmly lock water in the organohydrogel network,\nthereby endowing the GL–organohydrogel with the antifreezing\nproperty, long-term stability, and moisture lock-in capability. Our\norganohydrogel could endure extremely low temperature (−80\n°C) over 30 days without freezing and retain its water content\n(almost 100% of its initial state) after being stored at room temperature\n(25 °C, 54% humidity) for 30 days. It also demonstrated desired\nstretchable properties, conductivity, three-dimensional (3D) printability,\nand self-healing ability. A wearable data glove was constructed by\nusing the GL–organohydrogel and digital light processing technology.\nThis work opens a new avenue for developing hydrogels with long-term\nstability, moisture lock-in capability, and extreme-temperature tolerance\nfor stretchable electronics.