High-Strength Nanocomposite Hydrogels with Swelling-Resistant and Anti-Dehydration Properties

Abstract

Hydrogels with excellent mechanical properties have potential for use in various fields. However, the swelling of hydrogels under water and the dehydration of hydrogels in air severely limits the practical applications of high-strength hydrogels due to the influence of air and water on the mechanical performance of hydrogels. In this study, we report on a kind of tough and strong nanocomposite hydrogels (NC-G gels) with both swelling-resistant and anti-dehydration properties via in situ free radical copolymerization of acrylic acid (AA) and N-vinyl-2-pyrrolidone (VP) in the water-glycerol bi-solvent solutions containing small amounts of alumina nanoparticles (Al2O3 NPs) as the inorganic cross-linking agents. The topotactic chelation reactions between Al2O3 NPs and polymer matrix are thought to contribute to the cross-linking structure, outstanding mechanical performance, and swelling-resistant property of NC-G gels, whereas the strong hydrogen bonds between water and glycerol endow them with anti-dehydration capacity. As a result, the NC-G gels could maintain mechanical properties comparable to other as-prepared high-strength hydrogels when utilized both under water and in air environments. Thus, this novel type of hydrogel would considerably enlarge the application range of hydrogel materials.

Novel Chitosan-Silica Hybrid Hydrogels for Cell Encapsulation and Drug Delivery

“…Chitosan is degradable at a relatively slow rate, however, in the presence of lysozyme, the degradation was accelerated. According to a previous study, the incorporation of glycerol in the hydrogel systems which contained acrylic acid, N-vinyl-2-pyrrolidone affected the degradation rate, as more than 40% glycerol content in the hydrogel caused destruction of the hydrogen bonds between polymer chains, which decreased the cross-linking density of gels [72]. That phenomenon may have explained the rapid degradation of the hydrogels in the present study over the first few days followed by the subsequent slower degradation.…”

Ultrastable Zinc Anodes Enabled by Anti-Dehydration Ionic Liquid Polymer Electrolyte for Aqueous Zn Batteries

“…After 9 h, IL-PAM maintains 73% of its initial weight; however, PAM and the LE lose more than 65% of their initial weight. The reason why PAM loses less water is that the abundant hydroxyl groups in the polymer chain form hydrogen bonds with water molecules. , As shown in Table S3, compared to other previously reported hydrogel electrolytes, IL-PAM exhibits an excellent anti-dehydration property under extremely low humidity. − Conductivity is closely related to the water content of the electrolyte. As shown in the conductivity-time curves (Figure c), in an unsealed environment at 50 °C, the conductivity of the LE continues to decrease as water evaporates until it fails after 10 h, and the LFP|Zn battery with the LE fails after a few cycles due to a huge charge transfer resistance and kinetics sluggish (Figure d).…”

Transparent and Flexible Electronics Assembled with Metallic Nanowire-Layered Nondrying Glycerogel

“…Certain studies have incorporated glycerol into hydrogels to attain nondrying properties by either dissolving the initial reactants in glycerol before forming the gel or by incubating a preformed hydrogel in a solution containing glycerol after formation. − However, most studies simply weigh the glycerol-incorporated gels while exposing them to air at various time points and conclude the gels are nondrying. − These studies address little about the mechanism by which the gels remain wet in air. , Simulations using density functional theory have modeled the interaction between water, glycerol, and the polymer in a nondrying gel. However, these simulation results were mainly used to support the experimental observation that the total gel mass did not change over time . A certain study used thermal gravimetric analysis and differential scanning calorimetry to show that glycerol slows the evaporation of the liquid in a gel.…”