Flexible Gelatin/PVA/LNH Salogels for Synergistic Hygroscopic and Thermal Management

Abstract

With the global energy shortage and deterioration of the human living environment as well as the increasing demand for personal protective equipment under extreme environments, phase change materials (PCMs) have received much attention due to their excellent energy storage and reusability. Herein, lithium nitrate trihydrate (LNH), one of the particularly promising low-temperature salt hydrate PCMs, was encapsulated with three-dimensional (3D) gelatin/polyvinyl alcohol (PVA) cross-linking networks to fabricate flexible, stretchable, and form-stable phase change salogels. Specifically, the salogels were fabricated by dissolving macromolecular gelatin and PVA in melted LNH and then cross-linked using 1,4-butanediol diglycidyl ether (BDDE). The encapsulation using a 3D cross-linked polymer network can effectively solve the problems of melting leakage/flowing and water-loss drying/hygroscopic deliquescence of LNH. The results showed that the gelatin/PVA/LNH salogels exhibit good form stability, high latent heat (~170.9 J g⁻¹), and excellent hygroscopic properties with the saturation water absorption of dry gels up to 1.730 g g⁻¹. Meanwhile, the gelatin/PVA/LNH salogels show good mechanical properties, and their elongation at break could reach 1086%. Therefore, these hygroscopic phase change salogels are expected to be applicable in wearable devices for human low-temperature thermal and humidity management.