Microporous activated carbon filled anti-freezing hydrogels used for low-temperature applications

Self-healing and anti-freezing hydrogels have attracted great attention as their ability to work stably in harsh environments. In this manuscript, we design a dual self-healing and anti-freezing hydrogels based on functionalized microcapsules and phytic acid (PA). Based on mussel-inspired chemistry, polydopamine (PDA) is wrapped on microporous activated carbon (MAC) to obtain functional microcapsule (LO@MAC@PDA), which is loaded with linseed oil (LO). The stronger hydrogen bonds between PA and water weakens the intermolecular between water, effectively reducing the freezing point of the hydrogel and enabling the hydrogel to maintain good flexibility at −20 °C. The dual self-healing effect of LO@MAC@PDA gives the hydrogel a self-healing efficiency of 93.5% at −20 °C. The PA-LMP/PVA hydrogel is assembled into hydrogel-based flexible sensors to achieve sensitive detection of human motion at low temperatures. We expect that this simple strategy to expand the temperature range for using of hydrogel-based flexible sensors.