Synthesis of high strength, high elasticity, self-healing deep eutectic ionic elastomers based on multiple non-covalent interactions by using biobased glycerol monomer HPA for strain sensors

Abstract

Deep eutectic ionic elastomers (DEIEs) have emerged as a research focus in flexible ionic conductors due to their advantages, including rapid and convenient preparation processes, excellent mechanical and electrical properties. However, there remains an obvious research gap in developing DEIEs with superior comprehensive mechanical properties using greener biobased monomers and simpler formulations. In this study, two novel LiTFSI(lithium bis(trifluoromethane sulfonimide))-based polymerizable deep eutectic solvents systems: HPA(2-hydroxy-3-phenoxypropyl acrylate)/LiTFSI and HEA (2-hydroxyethyl acrylate)/LiTFSI were successfully discovered. Notably, the biobased monomer HPA was utilized for the first time in constructing PDES (polymerizable deep eutectic solvents), and then DEIEs were successfully prepared by UV-initiated free radical random copolymerization using these 2 kinds of PDES. The DEIEs’ polymer networks exhibit various non-covalent interactions, such as hydrogen bonds, dipole-dipole interactions, and π-π interactions, which endow them with high mechanical strength (2.76 MPa), good stretchability (687%), and high elasticity. These abundant physical interactions also confer the material with good self-healing capabilities. Moreover, the DEIEs demonstrate good transparency, sufficient ionic conductivity, and a wide operating temperature range. This material can not only be used for sensing and detecting conventional human physiological activities but also maintains stable sensing performance under complex conditions, such as mechanical damage and low-temperature environments, showcasing significant potential in flexible sensing applications.