The polyhydrogen bond stretchable waterborne polyurethane film with excellent self-healing properties

The fabrication of self-healing dielectric elastomers that are capable of effective recovery from both electrical breakdown and mechanical damage represents a valuable advancement in the field of actuators. However, the mechanical and dielectric properties of the materials may be compromised during the repair process, which has thus far limited their application as dielectric elastomers. In this work, we have developed a self-healing polyurethane film based on hydrogen bonding interactions by incorporating tannic acid (TA), which has been shown to retain high mechanical properties and excellent dielectric performance. The incorporation of TA has been demonstrated to enhance the efficiency of the damage in question is mechanical or electrical breakdown. The tensile strength of WPU/TA_0.42 that had been subjected to mechanical damage was restored by up to 97.51 % after 48 h. Following an electrical breakdown, a 60 % ethanol solution was applied to the damaged surface of the samples in order to remove the deposited carbides. The breakdown strength of WPU/TA_0.42 recovered close to 100 %, and it was demonstrated to be capable of being re-braked stably at 80MV/m. It is noteworthy that WPU/TA_0.42 exhibits enhanced mechanical and dielectric properties which can be attributed to the increased formation hydrogen bonds at crosslinking sites and interfacial polarization. This work presents a straightforward approach to fabricating dielectric elastomers with enhanced mechanical and dielectric properties capable of efficient self-healing following mechanical damage and electric breakdown.