A Waterborne Epoxy Vitrimer: Enabling Moisture-Driven Actuation, Continuous Moist-Electric Generation, and...

The integration of multiple hydroxyl structures presents a robust strategy for designing epoxy vitrimers based on transesterification reactions (TERs), enabling the realization of optimal dynamic properties. Nevertheless, significant challenges persist in achieving eco-friendly synthesis, hydrophilic-related functionalities, and sustainable degradation. Here, a catalyst-free waterborne epoxy vitrimer is developed by curing 1,4-butanediol diglycidyl ether with natural L-tartaric acid (L-TA), effectively addressing these challenges simultaneously. Harnessing the synergistic effects of multiple hydroxyl groups and the neighboring group participation effect imparted by L-TA, the resulting vitrimer exhibits rapid stress relaxation (τ^* = 270 s at 190 °C) and undergoes complete degradation in 95 °C pure water within 6 h. Furthermore, the abundant hydroxyl groups on polymer chains facilitate its function as a moisture-responsive actuator, achieving a crimping speed of 0.32 mm s^-1. Building on this, a moist-electric generator is engineered by utilizing the vitrimer as a matrix for ambient vapor collection and subsequent conversion into electrical energy. This device sustains a stable voltage output (0.42-0.50 V) under ambient conditions for 60 h, with capabilities for series amplification and capacitor charging. This study maximizes the potential of hydroxyl-rich TERs-based epoxy vitrimers, paving the way for the advancement and practical implementation of sustainable polymers.