Dual-Network Ionic Liquid Gels with Excellent Mechanical Properties for Flame-Retardant Fabric Coatings

The majority of existing single-network ionic liquid gels (ionogels) exhibit suboptimal strength and toughness, and enhanced mechanical properties have the potential to expand the applications range. We present a straightforward one-step polymerization method, followed by vacuum drying and dehydration treatment, preparing synergistically tough P(AB-co-HB) double-network ionogels. The rigid component is constituted by the PAB ionogel, which is polymerized from acrylamide (AM) and 1-butyl-3-methylimidazole chloride ([BMIM]Cl). The elastic component is constituted by the PHB ionogel, which are polymerized from hydroxyethyl methacrylate (HEMA) and 1-butyl-3-methylimidazole tetrafluoroborate ([BMIM]BF₄). The combination of the elastic and rigid components significantly enhanced the fracture strength (2401.7 ± 130 kPa), toughness (∼18.6 ± 0.8 MJ/m³), and stretchability (∼1345%) of the ionogels. Concurrently, double-network ionogels can readily adhere to various substrates, leaving no residue or irritation on the surface after removal. P(AB-co-HB) ionogel-fabric laminates have the potential to reduce the flammability of fabrics, while exhibiting outstanding thermal insulation and flame retardant properties.