Preparation and Properties of Self-healing Triboelectric Nanogenerator Based on Waterborne Polyurethane Containing Diels–Alder Bonds

A type of waterborne polyurethane (WPU) with excellent self-healing and recyclable properties was successfully prepared by introducing Diels–Alder (DA) reaction groups into it. FT-IR was used to verify the successful synthesis of samples and the retro-DA reaction in the WPU-DA films. It was found that the self-healing efficiency of the WPU-DA-4/4 films was 72.8%. After four cycle times, the self-healing efficiency could still achieve 49.7%. Moreover, the WPU-DA film could be applied as the positive friction layer to prepare a triboelectric nanogenerator (TENG). Working in contact-separation mode, the electrical outputs with 2 × 2 cm 2 area can reach 58 V, 3.2 µA, 17.6 nC, respectively. It is also interesting to find that the electrical output properties of the TENG after damage-healed can be restored to more than 90% of the original one. The cross-linked WPU had good reprocessability and had great potential application prospects in intelligent materials.