Tough, Transparent, and Multifunctional Zwitterionic Eutectogels Enabled by Metal-Salt Deep Eutectic Solvents

Deep eutectic solvent (DES)-based eutectogels are emerging as promising candidates for flexible sensors owing to their intrinsic ionic conductivity, nonvolatility, biocompatibility, and cost-effectiveness. However, conventional eutectogels are typically mechanically weak, as they lack efficient mechanisms to dissipate energy through reversible molecular interactions. In this work, we demonstrate the rational design of transparent and ultratough eutectogels achieved by in situ polymerization of sulfobetaine vinylimidazole (VIPS) in a ZnCl2–acetamide (ZnCl2–AcAm) Type IV metal-salt DES. In this system, the sulfonate groups on PVIPS chains dynamically coordinate with Zn2+, while the adjacent imidazolium rings stabilize these interactions through dipole–dipole and π–π associations. Meanwhile, acetamide molecules form extensive hydrogen bonds with sulfonate and imidazolium groups of PVIPS, providing an additional dynamic cross-linking network. The resulting eutectogel exhibits outstanding mechanical performance with a tensile strength of 3.95 MPa, toughness of 19.78 MJ m–3, stretchability of 683%, and high optical transparency of 90%. The eutectogels also display multifunctional features including self-healing, adhesion, shape memory, and stable mechano-ionic coupling, which enable sensitive responses to strain, pressure, and temperature. These results establish the integration of zwitterionic polymers with metal-salt DESs as a distinctive strategy for designing adaptive eutectogels, advancing the development of flexible and wearable electronics.