Simple Fabrication of Silica Amino Sphere-Reinforced Ionic Liquids/Graphene Conductive Hydrogel Sensors with Super Toughness, Self-Healing, and Strain Sensitivity Properties

Conductive hydrogels have gained considerable interest in their potential applications in fields such as soft robotics, electronic devices, and wearable technology. However, their widespread use has been limited due to the inherent brittleness of conventional hydrogels. In response to this challenge, we have engineered a multifunctional conductive hydrogel, characterized by dual physical cross-linking networks, using a simple, one-pot method. Our design incorporates acrylamide (AM), lauryl methacrylate (LMA), graphene (GN), silica amino spheres (SiO2-NH2), and 1-hexadecyl-3-methylimidazole chloride (ILs). Notably, the LMA, SiO2-NH2 spheres, and AM play key roles in energy dissipation through hydrophobic association and hydrogen bonding, serving as dynamic cross-linking points. This structural configuration endows our resultant PAM@SiO2-NH2/(ILs-GN) hydrogels with impressive tensile strains, peaking at an extraordinary 15,318%, along with super toughness measuring 51.4 MJ/m3 and self-healing capabilities. Moreover, the ILs facilitate effective dispersion of graphene, leading to superior conductivity and stable resistance changes in the hydrogel, with a conductivity measurement of 12 mS/cm. The hydrogel also demonstrates high sensitivity, with a gauge factor of 18.94 at a strain of 1200%. When implemented as a strain sensor, the hydrogel capably monitors a broad spectrum of human movements in real time, capturing both large-scale deformation and minute, nuanced motions. The culmination of these findings suggests the immense potential of our hydrogel sensors for use in flexible electronic skin applications, establishing them as promising candidates for multifunctional sensors and flexible electrodes.