Inorganic Salts Induce Thermally Reversible and Anti‐Freezing Cellulose Hydrogels

Inspired by the anti‐freezing mechanisms found in nature, ionic compounds (ZnCl2/CaCl2) are integrated into cellulose hydrogel networks to enhance the freezing resistance. In this work, cotton cellulose is dissolved by a specially designed ZnCl2/CaCl2 system, which endows the cellulose hydrogels specific properties such as excellent freeze‐tolerance, good ion conductivity, and superior thermal reversibility. Interestingly, the rate of cellulose coagulation could be promoted by the addition of extra water or glycerol. This new type of cellulose‐based hydrogel may be suitable for the construction of flexible devices used at temperature as low as −70 °C. Frostschutzmittel: Gefrierschutz‐Cellulosehydrogele mit thermisch reversiblem Sol‐Gel‐Übergang wurden in wässriger ZnCl2/CaCl2‐Lösung hergestellt. Zn2+ trägt dabei zur Auflösung von Cellulose bei, und Ca2+ wirkt als Geliermittel. Diese Hydrogele können Anwendung in flexiblen und am Körper tragbaren Geräten für eine Verwendung bis hinab zu −70 °C finden.