Mechanically robust eutectogels enabled by precisely engineered crystalline domains.

Eutectogels have emerged as promising candidates for technological applications due to their environmental stability, repeatable deformability, and high ionic conductivity. Nevertheless, the existing eutectogels often show fragile network structures, in which the simultaneous achievement of high modulus, strength, and toughness remains a real challenge. Herein, a variable-temperature solvent exchange (VTSE) strategy is proposed to fabricate mechanically robust eutectogels. The VTSE approach implements a two-stage solvent exchange process to synergistically optimize the crystal nucleation and growth of poly(vinyl alcohol), resulting in a robust network crosslinked by well-developed crystalline domains. The obtained eutectogels exhibit an advantageous combination of high Young's modulus (103.1 MPa), strength (40.5 MPa), toughness (86.8 MJ m), and fracture energy (98.7 kJ m), surpassing the performance of conventional hydrogels, organogels, and ionogels. Moreover, the versatility of VTSE approach allows its application to other solvent systems, providing a powerful platform for the design of advanced functional gels.