Simple Fabrication\nof Silica Amino Sphere-Reinforced\nIonic Liquids/Graphene Conductive Hydrogel Sensors with Super Toughness,\nSelf-Healing, and Strain Sensitivity Properties

Abstract

Conductive\nhydrogels have gained considerable interest in their\npotential applications in fields such as soft robotics, electronic\ndevices, and wearable technology. However, their widespread use has\nbeen limited due to the inherent brittleness of conventional hydrogels.\nIn response to this challenge, we have engineered a multifunctional\nconductive hydrogel, characterized by dual physical cross-linking\nnetworks, using a simple, one-pot method. Our design incorporates\nacrylamide (AM), lauryl methacrylate (LMA), graphene (GN), silica\namino spheres (SiO₂-NH₂), and 1-hexadecyl-3-methylimidazole\nchloride (ILs). Notably, the LMA, SiO₂-NH₂ spheres,\nand AM play key roles in energy dissipation through hydrophobic association\nand hydrogen bonding, serving as dynamic cross-linking points. This\nstructural configuration endows our resultant PAM@SiO₂-NH₂/(ILs-GN) hydrogels with impressive tensile strains, peaking\nat an extraordinary 15,318%, along with super toughness measuring\n51.4 MJ/m³ and self-healing capabilities. Moreover, the\nILs facilitate effective dispersion of graphene, leading to superior\nconductivity and stable resistance changes in the hydrogel, with a\nconductivity measurement of 12 mS/cm. The hydrogel also demonstrates\nhigh sensitivity, with a gauge factor of 18.94 at a strain of 1200%.\nWhen implemented as a strain sensor, the hydrogel capably monitors\na broad spectrum of human movements in real time, capturing both large-scale\ndeformation and minute, nuanced motions. The culmination of these\nfindings suggests the immense potential of our hydrogel sensors for\nuse in flexible electronic skin applications, establishing them as\npromising candidates for multifunctional sensors and flexible electrodes.