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.
Rewritable paper exhibits the potential to replace conventional paper due to its reusable properties. However, compared to conventional paper, rewritable paper can fade, making it impossible to store information stably for a long time in a daily environment, which limits its application. Here, a series of photochromic gelatin/polyvinyl alcohol (PVA) composited films containing polyoxometalate were prepared. The addition of PVA had a significant effect on the mechanical, transparent, photochromic and fading properties of the film. The addition of PVA significantly inhibited the fading process of the film after photochromism. This was due to the increase of crosslink density in the film and the existence of hydrogen bonding between PVA and inorganic photochromic ammonium molybdate. Despite this, the film was able to achieve complete fading in 1.5 days in a humid environment and the fading time could be further accelerated to 2 h by heating. This film could display information stably over a long time while being rewritable. It was expected that this simple and effective design strategy is conducive to the development of a new generation of rewritable paper.
危险品化学品经营许可证（带存储）