Hydrogels possess great application potential in the fields of flexible electrodes and batteries

flexible sensors and soft robots. Usually

hydrogels freeze and become rigid

brittle

and non-conductive when the temperature decreases below the freezing point of water

severely limiting their use in this temperature range. To solve the weakening and failure of hydrogel at low temperature

the researchers designed and prepared a series of anti-freezing hydrogel materials through various methods. Ionic compounds and organic anti-freezing solvents play important roles in anti-freezing hydrogels system

ionic compounds could lower the freezing point of hydrogels and also provide the conductive capacity of hydrogels. A high concentration of solutes (e.g.

ethylene glycol

glycerol) is introduced into hydrogels to depress the water freezing point

and the combination of ionic compounds and organic anti-freezing solvents is applied to produce anti-freezing hydrogel materials. The mechanical flexibility

conductivity of the prepared hydrogels at subzero temperature were studied and measured. The response function at subzero temperature of the resulting hydrogel-based flexible electronics

such as a capacitive sensor

a resistive sensor and an actuator

were explored and developed. Recent progress made in preparation

properties and applications of anti-freezing hydrogels is reviewed

the prepared method which includes various anti-freezing solvent media systems was discussed

and the challenges in anti-freezing hydrogels such as biocompatibility

toxicity of anti-freezing solvents will be expected to be met and resolved.