Nanocomposite Hydrogels Enhanced by Cellulose Nanocrystals Stabilized Pickering Emulsions with Self-Healing Performance in Subzero Environment

Abstract Nowadays, hydrogels as flexible materials have attracted considerable attention in frontier fields such as wearable electronic devices, soft actuators and robotics. However, most hydrogels use water as matrix will inevitably freeze at subzero and damage in severe environment, which greatly reducing their service life and practical value. Herein, nanocomposite hydrogels with self-healing performance at subzero temperatures were proposed by introducing binary water-glycerol continuous phase and dual self-healing interactions. The efficacy of binary solvents was emphasized in preventing formation of ice crystals, enhancing flexible and self-healing abilities of hydrogels in subzero environment. Particularly, linseed oil (LO) as healing agent was effectively loaded in Pickering droplets by cellulose nanocrystals (CNCs). Due to external healing agent and non-covalent bonding, hydrogels showed good self-healing performance at subzero temperature (the healing efficiency could be up to 80.1% for 12 h at -20 ℃). Thus, the designed hydrogels demonstrated multifunctional properties to overcome adverse conditions, which greatly elevated their durability and practicality.