A stretchable, compressible and anti‐freezing ionic gel based on a natural deep eutectic solvent applied as a strain sensor

Abstract Glycerin (Gly), a common by‐product in petrochemical industry, is used as hydrogen bond donor. Green organic choline chloride (ChCl) as hydrogen bond acceptor. Natural deep eutectic solvent (NDES) can be prepared with Gly and ChCl. Subsequently, a starch/NDES ionic gel is prepared by in situ free radical polymerization of acrylamide monomer in NDES with starch as the reinforcement. The effects of amylose content in starch and starch addition amount on mechanical properties of ionic gel are analyzed. The results show that starch could be partially dissolved and dispersed in NDES. Compared with the tensile strength of pure NDES gel (about 15 kPa), the tensile strength of starch/NDES ionic gel is increased by 6 times to 90 kPa. It shows good self‐recovery performance after 20 compression cycles. Starch/NDES ionic gel has good thermal stability and frost resistance. In addition, CS4 starch/NDES ionic gel has the highest conductivity. At the same time, starch/NDES ionic gel has been successfully applied to monitor grasping motion of hand, which has the potential of strain sensor. It provides a new green method for the design of electronic products such as electronic skin.