Harnessing Phase Separation and Solvation to Engineer Robust, Stretchable Gels

Organogels emerge as an important class of gels with diverse potential applications. Yet their uses often remain limited by poor mechanical performance. Although working mechanisms that promote polymer–polymer interactions, such as phase separation, have been studied, the role of polymer–solvent interactions in controlling gel toughness and extensibility remains seldomly explored1 . Synergizing both interactions could improve gels’ mechanics, which, however, is challenging because of their often-competing nature. Herein, we propose and validate an innovative and general scheme to engineer ultra-tough, stretchable gels by exploring both phase separation and polymer-solvation interactions. As a proof-of-concept, we successfully create hierarchical gels from polyacrylic acid (PAA) and polyvinyl alcohol (PVA) in dimethylformamide (DMF) showing excellent mechanical properties, and further extend the design principle towards a range of polar aprotic solvents, including acetone, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), and propylene carbonate (PC). The resulting gels demonstrate outstanding tensile strength to 62.5 MPa, fracture energy of ~410.9 MJ m⁻³, stretchability over 3000%, and controlled stiffness ranging from ~3 MPa (soft) to 1 GPa (thermoplastic-like). These gels further show enhanced impact resistivity, high energy absorption, long-term stability, and strong surface adhesion, critical for myriad real-world applications. This work could open a new pathway for rationally creating an array of gels with designed mechanical performances, relevant to wearable electronics, soft robotics, drug delivery, and energy storage devices.