UV-induced ferric phytate access to fast gelation of conductive and anti-freezing hydrogels for cryogenic strain sensing

Conductive hydrogels have great potential in flexible electronics due to their flexibility, excellent biocompatibility and diverse functionalities. However, most rapid-gelation hydrogels tend to manifest weak and fragile due to vigorous reaction process and poor adaptability in cryogenic environment, which severely impede their practical applications. Herein, a facile and mild strategy for rapid gelation is proposed that accelerates polymerization by generating reactive oxygen radicals via electron transfer based on the excitation of ferric phytate ligands under UV irradiation, which takes only 17 s to initiate. Interestingly, the introduced phytic acid imparts the hydrogel excellent electrical conductivity (12 ms/cm), frost resistance (−31℃) and improves tensile properties (elongation at break 1299 %). The hydrogel that combines the above merits inspires the construction of strain sensor for monitoring physiological activity of low-temperature environments. This study provides a simple and universal approach for the rapid preparation of antifreeze hydrogels and reinforces the focus on sustainable and high-value utilization of phytic acid in advanced applications.