Physically crosslinked amphiphilic eutectogels with underwater self-healing, strong adhesion, environmental stability and closed-loop recyclability for underwater sensing and information transmission

Eutectogels are emerging as soft material with great promise for application in soft electronics. However, they are generally unable to maintain autonomous self-healing and adhesiveness in submerged and humid environments, which causes some limitations to their applicability. Moreover, they often fail to undergo closed-loop recycling, due to the general presence of chemical cross-linking. Here, a amphiphilic eutectogel synthesized via a one-step photopolymerization strategy within a tailored deep eutectic solvent (DES) system, employing purely physical cross-linking mechanisms. Underwater, nanoscale phase-separated structures (~14.6 nm), triggered by hydrophobic aggregation in solution, arise from dominant hydrophobic interactions among polymer chains. These distinct domains facilitate efficient water drainage at the gel–substrate interface and impart excellent water resistance. The resulting eutectogel exhibits autonomous self-healing and robust adhesion in both air and underwater environments. The eutectogel could achieve closed-loop recycling without affecting their mechanical properties and adhesive performance. By finely tuning the dynamic interactions between polymer chains and DES, the gel achieves a physically crosslinked polymeric network with enhanced mechanical resilience and environmental stability across broad temperature ranges. The DES acts as a medium for monomer polymerization, facilitating synergistic interactions and homogeneous phase distribution, enabling synergistic interactions between hydrophilic and hydrophobic monomers, offering a universal strategy for eutectogel fabrication. The presence of freely mobile ions allows the gel to function as both a strain and pressure sensor in air and underwater, including applications in human motion sensing and information transmission, highlighting its immense potential for multifunctional sensing and wearable systems.