Glassy Eutectogels with Superior Impact Resistance and Fire Protection Enabled by Localized Solvation

Abstract Eutectogels, polymeric networks swollen within deep eutectic solvents (DESs), hold tremendous promise as lightweight and soft armour in the field of impact protection. However, current impact‐resistant eutectogels not only heavily depend on complicated fabrication processes to overcome mechanical defects, but lack reliable fire safety, struggling to afford practical applications. Herein, by leveraging the mussle‐inspired interlocked phase structures and intumscent flame‐retardant mechanism, a simple way is reported to address this issue via copolymerizing vinylphosphonic acid (VPA) and N, N‐dimethylacrylamide with divergent hydrogen bond affinities in a polyhydroxy DESs. Due to the stronger association between VPA and DESs, the obtained copolymers undergo localized solvation, affording hydrogen‐bond interconnected bicontinuous phase structures with large modulus contrast. Profiting from the efficient stress transfer and dissipation between the separated phases, the eutectogel not only features ultrahigh modulus (498.6 MPa), energy dissipation rate (90%) and adhesive strength (3.9 MPa), but peerless compressive strength (130.2 MPa) under high‐velocity impact load, which surpasses the most reported impact‐resistant gels. Besides, when exposed to fire, the eutectogel preferentially forms thermally insulating intumescent char layers rather than burning, which contributes to protecting substrates and mitigating fire hazards. This work provides useful inspiration to engineer next‐generation soft protective materials.