Synthesis And Characterization Of Self-Healing Dielectric Supramolecular Elastomers Base On Hydrogen Bonding

Self-healing elastomers are able to repair mechanical damage on themselves spontaneously or with the aid of a stimulus.And their self-healing properties have attracted wide attention from researchers.The self-healing ability relies on dynamic covalent bonds and noncovalent interactions.The hydrogen bonds in noncovalent bonds have attracted much attention due to their advantages such as directivity,orientation and effective construction of supramolecular elastomer networks.Nowadays,there is an increasing need to develop multifunctional polymers by the combination of various predefined functions.Although self-healing elastomers based on supramolecular assemblies have been investigated,there has been no focus on dielectric properties.The aniline tetramer has the properties of high dielectric and low modulus similar to polyaniline,so we added aniline tetramer into the reaction system to make the self-healing elastomer have a certain dielectric property.We synthesized carboxyl-capped aniline tetramer by oxidative coupling.The FT-IR results showed that aniline tetramer contained quinone ring and benzene ring,and there was a carboxyl group that reacted with diethylenetriamine;The TGA test of aniline tetramer showed that aniline tetramer had good thermal stability;The UV test of aniline tetramer showed that aniline tetramer had electrochemical properties.Based on previous studies,we demonstrated a new design strategy to produce a self-healing dielectric elastomer by synthesizing an aniline tetramer(AT)-functionalized supramolecular elastomer(SE-AT).’H NMR test results showed that the addition of aniline tetramer was beneficial to the formation of 1,1-dialkyl urea or urea capped 1,3-dialkyl urea;DSC and XRD result demonstrated that the termination of AT in supramolecular system not only shortened linear amide molecular chain to decrease glass transition temperature,but also destroyed the crystallization to achieve amorphous structure.Tensile curve showed that the self-healing dielectric elastomers had good elongation at break and self-healing properties.Self-healing property of SE-AT20%was the best,and self-healing efficiency of SE-AT20%can achieve complete healing of 100%after 24h.At the same time,the material also exhibited good dielectric properties.The maximum actuated strain significantly increased with the increasing AT content.Moreover SE-AT exhibited the ability to regaining actuated strain at electric field after self-healing.