The Polymer Society of Korea

Abstract

Hydrogels are limited by poor thermal stability and insufficient stiffness. Glycol was introduced as a solvent to ensure long-term stability, leveraging its low vapor pressure and wide thermal window. Due to its lower hydrogen bonding density and polarity relative to water, glycol promotes enhanced polymer-polymer interactions. This suppresses solvent-induced plasticization, yielding a gel network with significantly improved structural robustness. We report tough glycol gels with a bicontinuous morphology of glassy and solvent-compatible domains, as evidenced by a single glass transition temperature (T_g). This integrated network achieves a work of fracture of 30 MJ/m³, and exhibits pronounced hysteresis that dissipates mechanical energy efficiently. Unlike permanently damaged soft materials, the stress–strain response is largely restored after brief annealing above the T_g. Owing to glycol’s low volatility, the gels strongly resist evaporation and remain stable.