Skin-Inspired\nGels with Toughness,\nAntifreezing, Conductivity, and Remoldability

Abstract

In recent years, nature-inspired conductive\nhydrogels have become ideal materials for the design of bioactuators,\nhealthcare monitoring sensors, and flexible wearable devices. However,\nconductive hydrogels are often hindered by problems such as the poor\nmechanical property, nonreusability, and narrow operating temperature\nrange. Here, a novel skin-inspired gel is prepared via one step of\nblending polyvinyl alcohol, gelatin, and glycerin. Due to their dermis-mimicking\nstructure, the obtained gels possess high mechanical properties (fracture\nstress of 1044 kPa, fracture strain of 715%, Young’s modulus\nof 157 kPa, and toughness of 3605 kJ m^–3). Especially,\nthe gels exhibit outstanding strain-sensitive electric behavior as\nbiosensors to monitor routine movement signals of the human body.\nMoreover, the gels with low temperature tolerance can maintain good\nconductivity and flexibility at −20 °C. Interestingly,\nthe gels are capable of being recovered and reused by heating injection,\ncooling molding, and freezing–thawing cycles. Thus, as bionic\nmaterials, the gels have fascinating potential applications in various\nfields, such as human–machine interfaces, biosensors, and wearable\ndevices.