Rapid Self-Healing Polyurethane Elastomer Based on Ionic Aggregation for Triboelectric Nanogenerator

Self-healing materials are urgently needed in the electronics due to their ability to significantly extend product lifespan and reduce maintenance costs. However, achieving a balance between self-healing efficiency and mechanical properties remains a challenge. To overcome the challenge, a rapid self-healing polyurethane (IL-PU) is proposed on the basis of introducing dynamic ionic exchange method. To realize the method, hydroxyl-functionalized carboxylic acid and hydroxyl-functionalized imidazolium salts are introduced into the linear polyurethane system as chain extenders, resulting in imidazolium and carboxyl groups hanging from the main chain and work as stickers. In IL-PU regime of polyurethane matrix, the nano aggregates formed between imidazolium and carboxylate groups serve as physical crosslinking sites. These dynamic interactions allow the continuous rearrangement of the network at room temperature. It is shown that an increase in the content and length of imidazolium alkyl chain could also promote the self-healing ability. Based on self-healing elastomer (IL-PU), a triboelectric nanogenerator (IL-PU-TENG) was fabricated, with an open circuit voltage (Voc) of 200 V, and a power density of 3.07 W·m-2, demonstrating outstanding electron-donating ability. Moreover, even after cutting, the output performance of IL-PU-TENG could rapidly recover within 2 h at 40°C.