Rational Design Strategy for High-Temperature-Tolerant Stretchable Hydrogels for Building Fire Protection

Polymer hydrogel is a promising material category for designing artificial skin, drug carriers, flexible electronic equipment, and self-healing building materials, which require good high-temperature resistance. Herein, an ultrastretchable polymer hydrogel resistant to high temperature is prepared by combining molecular self-assembly and in situ polymerization techniques. Fracture strain of the as-prepared hydrogel exceeds an unexpected 62 times, based on the ionic cross-linking of the Mg-ion and amide group of polyacrylamide (PAM). PAM frameworks retain a highly active amorphous state in harsh high-temperature vacuum environments due to Mg-ion cross-linking. Amorphous PAM frameworks inhibit the growth of magnesium chloride nanocrystals, resulting in the formation of a super porous sponge structure. The special microstructure enables the material to rapidly absorb water vapor from a humid environment, thereby restoring its inherent mechanical properties. The as-prepared composite provides a research direction for the design and application of a high-temperature-resistant polymer hydrogel.