Hand-extended noodle inspired physical conjoined-network organohydrogels with anti-freezing, high stiffness and toughness properties

To obtain excellent anti-freezing, non-drying, mechanical properties and conductivity of polymeric materials is important and necessary to realize their wide applications in the fields of sensor and smart wearable devices. However, it is very difficult to keep all these performances well due to the antagonistic action in different properties. Herein, inspired by the Chinese hand-extended noodles that salt and cooking oil enhance the elasticity, stretchability, and non-drying, a new strategy to fabricate conjoined-network organohydrogel with multiple excellent performances is reported. By dissolving calcium chloride (CaCl2, as ‘salt’) into glycerol/water solution (as ‘oil’) as solvent, a physical conjoined-network organohydrogel composed of polyvinyl alcohol (PVA) and sodium alginate (Alg) with excellent performance was fabricated by a simple gelation and soaking two-step strategy. Under the synergy of CaCl2 and glycerol, the organohydrogel shows excellent anti-freezing performance below −42.1 °C, well non-drying property (72 h), outstanding mechanical properties (tensile strength of 2.11 MPa, elongation at break of 580% and Young’s modulus of 0.42 MPa), and well ionic conductivity (1.69 S m−1) by construct a conjoined-network, which provides a general strategy for the design of hydrogels with multiple outstanding performances due to a variety of the cross-linking mechanisms available and synergistic effect. It was foreseen that the conjoined-network organohydrogel might be widely used in multiple areas such as electric skin, artificial intelligence, and smart wearable devices.