Dual-Mechanism-Driven Environmental-Friendly Fast Self-Healing Ionic Hydrogels with Excellent Sensitivity to Strain Responsiveness

Ionic hydrogels have important value for applications in bionic skin and flexible sensor fields. However, general ionic hydrogels suffer from inevitable damage and reduction of service life after long-term use. Here, we propose a dual mechanism-driven strategy with a reversible metal coordination bond and dynamic hydrogen bond to construct a novel fast self healing ionic hydrogel via a facile "two-step" approach based on environmental-friendly natural resources as raw materials. The dual-mechanism-driven mode endows the hydrogel with excellent self-healing properties (3 h, 95.31%), tensile strength (479.8 kPa), compression strength (5.235 MPa), and fatigue resistance. The hydrogel also showed excellent self-adhesion performance, even underwater, as well as high and stable conductivity (sigma = 17.54 mS center dot cm-1). In addition, it has an ion-responsive deformation feature so that the hydrogel can be shaped and restored in different ion solutions. As a sensor on human skin, the high sensitivity (GF = 2.363) enables it to detect and distinguish various human movements and even different letter pronunciations and pulses. These excellent performances lay a solid foundation for its application in bionic skin and flexible sensor fields.