Strong and Tough Water-Tolerant Conductive Eutectogels with Phase-Separated Hydrophilic/Hydrophobic Dual Ionic Channels.

Abstract

Eutectogels are emerging as the next-generation stretchable electronics due to their superior ionic conductivity, non-volatility, and cost-effectiveness. Nevertheless, most eutectogels suffer from weak mechanical strength and toughness and pronounced hygroscopicity. Herein, a strategy is proposed to fabricate phase-separated eutectogels with dual ionic channels (PSDIC-gel), which exhibit exceptional integrative properties, especially water resistance. By blending hydrophilic/hydrophobic polymerizable deep eutectic solvents, dual ionic channels spontaneously form via polymerization-induced phase separation. The hydrophilic poly(acrylic acid) (PAA) phase containing Li⁺-channels, rich in hydrogen bonding and ion-dipole interactions, provides mechanical strength and conductivity. The hydrophobic poly(hexafluorobutyl acrylate) (PHFBA) phase incorporating cholinium cation (Ch⁺) channels enhances toughness, conductivity, and water resistance. Adjusting the phase ratio yields a microphase-separated transparent eutectogel with high tensile strength (6.03 MPa), toughness (16.18 MJ m^-3), excellent ionic conductivity (1.6 × 10^-3 S m^-1), strong substrate adhesion, and rapid room-temperature self-healing. Solid-state NMR reveals the conductive mechanism and the phase-separated structure featuring dual ionic channels in PSDIC-gels, advancing the understanding of complex ionic interactions at the atomic level. The PSDIC-gel enables a flexible triboelectric nanogenerator for accurate real-time self-powered human motion sensing. This work advances eutectogel design through structure-property engineering, offering a universal strategy to reconcile mechanical robustness, environmental suitability, and ionic conductivity for wearable electronics.