Strain-Stiffening Ionogel with High-Temperature Tolerance via the Synergy of Ionic Clusters and Hydrogen Bonds

Abstract

Highly stretchable and conductive ionogels have great potential in flexible electronics and soft robotic skins. However, current ionogels are still far from being able to accurately duplicate the mechanically responsive behavior of real human skin. Furthermore, durable robotic skins that are applicable under harsh conditions are still lacking. Herein, a strong noncovalent interaction, ionic clusters, is combined with hydrogen bonds to obtain a physically cross-linked ionogel (PCI). Benefiting from the strong ionic bonding of the ionic cluster, the PCI shows strain-stiffening behavior similar to that of human skin, thus enabling it to have a perception-strengthening ability. Additionally, the strong ionic clusters can also ensure the PCI remains stable at high temperatures. Even when the temperature is raised to 200 °C, the PCI can maintain the gel state. Moreover, the PCI exhibits high transparency, recyclability, good adhesion, and high conductivity. Such excellent features distinguish the PCI from ordinary ionogels, providing a new way to realize skin-like sensing in harsh environments for future bionic machines.

Impact of hydrogen bonding interaction energy on the polymerization kinetics of polymerizable deep eutectic solvent monomers

“…Currently, the conductor materials for flexible electronic devices are mainly composed of conductive polymers, 10,11 metal-based conductive materials, 12 hydrogels, 13–15 and ionic gels. 16–18 However, conductive polymers are generally complex and costly to prepare. A higher modulus of elasticity of metal-based conductive materials will lead to stress concentration and fracture during bending or stretching, affecting the stability and reliability of the device.…”