A Smart Design Strategy for Super‐Elastic Hydrogel with Long‐Term Moisture, Extreme Temperature Resistance, and Non‐Flammability

Abstract

Elastic hydrogel is a promising material category for designing biological muscles, repairable building materials, flexible electronic devices, and vulcanized rubber substitutes, which is required to have a long life, good self‐healing performance and extreme temperature tolerance. Herein, a super‐elastic mineral hydrogel is developed with long‐lasting moisture, based on dynamic physical crosslinking between hydrated calcium ion clusters and amide groups of polyacrylamide (PAM). The complex hydrogel exhibits a super stretchability of 13 600% at room temperature, and can maintain the super flexibility in a wide temperature range of −40–50 °C or for a long period of 28 days. Particularly, the soft material cannot be ignited under an open flame at 400–500 °C, because of coupling dual flame retardant mechanisms containing the endothermic effect of liquid water evaporation and the barrier effect of calcium mineral salt on oxygen. In conclusion, the novel complex hydrogel with excellent tensile property, stability in extreme temperature or long operating time, and flame retardancy may become a promising candidate in the fields of agriculture, food, construction, medicine, and machinery.

Ultrastretchable Luminescent Nanocomposite Hydrogel with Self-Healing Behavior

“…In addition, five cycles of loading–unloading tests were carried out at 500% strain without rest. As shown in Figure d, the dissipated energy decreases after the first cycle, and the following hysteresis cycles almost overlap each other, indicating that the nanocomposite hydrogel has good fatigue resistance. , …”

“…As shown in Figure 1d, the dissipated energy decreases after the first cycle, and the following hysteresis cycles almost overlap each other, indicating that the nanocomposite hydrogel has good fatigue resistance. 29,30 Subsequently, photoluminescence properties of the nanocomposite hydrogels were investigated. The excitation spectrum of Eu 3+ -containing nanocomposite hydrogel is shown in Figure S9 (Supporting Information).…”

A high-thermopower ionic hydrogel for intelligent fire protection

“…S1a†). 26,27 In HTIG3, the characteristic peak of C–N + in PDDA shifted from 2070 cm −1 to 2098 cm −1 , indicating an electrostatic interaction between poly(AAm/AMPSA) and PDDA (Fig. 2a).…”

Hydrogels Enable Future Smart Batteries

“…However, concomitant side reactions in batteries at elevated temperatures may occur and cause permanent capacity fading or risk of fire (when organic electrolytes are employed). Hydrogels ward off fires due to the intrinsic endothermic effect of water evaporation and the oxygen barrier effect of inner salts, , but the hydrogels are still limited by the instability of the electrolyte/electrode interface. The external thermal management system cools down the batteries by fans or flowing liquids, which increases the complexity and footprint of the entire system.…”