Printable environmentally robust hydrophobic eutectogel sensors with high strength and strong adhesion for human–machine interaction

A water-resistant eutectogel with environmental stability was developed. • Balanced toughness, adhesion, self-healing, and ionic sensing were achieved. • Printable, structurally tunable gel devices designed for customized sensing needs. • Combining actuation with sensing for human–machine interaction. Flexible gel sensors for human-machine interaction are often constrained by trade-offs between environmental stability, mechanical robustness, interfacial adhesion, and multifunctional sensing. A printable hydrophobic eutectogel sensor with environmental robustness is reported, enabling operation in aqueous environments and under various temperature conditions. A hydrophobic deep eutectic solvent is constructed, followed by the introduction of the hydrophobic monomer and photopolymerization to form a three-dimensional network. Hydrogen bonding and hydrophobic association contribute to the gel's high strength and effective energy dissipation, while the non-covalent gel network provides toughness and self-healing properties. The eutectogel exhibits robust mechanical strength of 3.40 MPa and toughness of 19.03 MJ m −3 . Hydrophobic monomers effectively remove interfacial water and abundant carboxyl groups form multiple interactions with the substrate surface to establish strong interfacial adhesion strength of up to 897 kPa. Hydrophobic hydrogen acceptors and monomers reduce ion leakage and water penetration. The low glass transition temperature of the eutectogel ensures its anti-freezing performance, while the non-volatility of the eutectic solvent contributes to thermal stability. Stable ionic transport channels support multifunctional sensing, and the printability of the precursor facilitates the fabrication and integration of complex structural devices. Download: Download high-res image (239KB) Download: Download full-size image