Tough, Antifreezing, and Conductive Hydrogel Based on Gelatin and Oxidized Dextran

Abstract Forming natural polymers‐based hydrogels with enhanced mechanical strength, outstanding antifreezing property and superior conductivity is still a challenge. Here, gelatin/oxidized dextran hydrogel is fabricated and it shows enhanced mechanical performance, antifreeze tolerance, and conductivity due to the synergistic interaction of ammonium sulfate and betaine. The resulting gelatin/oxidized dextran/(NH₄)₂SO₄/betaine hydrogel exhibits high stretchability (570%), tough tensile (2.49 MPa) and compressive (46.41 MPa) fracture strength, favorable tensile (6.05 MJ m⁻³) and compressive (3.08 MJ m⁻³) toughness, antifreezing property (−30 °C) and high conductivity (2.86 S m⁻¹). Based on the above characteristics, the hydrogel is applied for strain sensor to monitor the joints motion of human body such as finger, wrist, elbow, knee, neck, and throat. The hydrogel can maintain good mechanical performance and stable sensing signal from 25 to −30 °C. Therefore, the designed hydrogel based on natural polymers shows a huge potential for tissue engineering and biosensing under the mild or extreme environment.