Electrothermally Regenerable PEDOT:PSS/PVA Composite Films for Solid-State Dehumidification Applications

Conventional thermal regeneration of solid desiccants is often hindered by high energy consumption. To address this challenge, we propose a novel scheme that eliminates the need for preheating the return air to regenerate the desiccant. Instead, moisture removal is achieved directly via electrothermal heating. To realize this, we employed a composite film strategy based on PEDOT:PSS and PVA, leveraging PEDOT:PSS’s dual hydrophilic and conductive properties while using PVA to improve mechanical robustness. EG is commonly used as a dopant and is considered to promote a conformational change of PEDOT chains from coiled to expanded structures. This transition may contribute to a more continuous conductive network and enhance π-π stacking and charge transport. Multiscale characterization and device-relevant testing were conducted to link the morphology and surface composition to mechanical durability, electrothermal stability, and moisture-sorption behavior. The composites demonstrated significant mechanical stability under cyclic tensile loading. Incorporating PVA markedly improved the mechanical robustness of the otherwise brittle PEDOT:PSS, increasing the elongation at the break to 630%. Moreover, the film maintained structural integrity during 100 loading–unloading tensile cycles to 20% strain under 25 °C and 80% RH. Electrothermal durability tests showed no significant electrical degradation during 12 h of continuous powering, indicating prolonged electrical stability. Water-vapor sorption measurements indicated that introducing PVA reduced the saturated uptake to 82% of the pristine film; nevertheless, the selected formulation (PP6) still exhibited a high absorption capacity of 1132.80 cm3 (STP) g–1 at P/P0 = 0.94, demonstrating strong moisture uptake in the high-humidity regime. Based on comprehensive performance evaluation, PP6 was used to produce the dehumidification element. The element displayed reversible absorption–desorption during electrothermal regeneration in cycling tests powered by approximately 10 W, confirming the composite’s viability via an electro-driven pathway. Overall, this study demonstrates a self-standing PEDOT:PSS-based polymer desiccant that simultaneously achieves humid-state mechanical durability and long-term electrothermal stability, enabling stable low-power regeneration cycling without thermally preheating high-flow-rate return air.