Rationally micropatterned antifogging hydrogels counteracting extreme condensation

Abstract Loss of transparency due to water vapor condensation is a widespread problem across diverse applications such as windows, eyewear, displays, vehicles, and kitchenware. Conventional antifogging strategies relying on hydrophilic or hydrophobic coatings, based on chemistry and/or nano-topography, can counteract up to mild water deposition, but lose functionality at excessive condensation environments. Here, we present a passive approach, rationally micropatterning an inherently hydrophilic hydrogel to maintain high transparency under supersaturation. Guided by optics and wetting theory, and employing a diffusion model to calculate related timescales of water film formation, we engineer a wicking structure on poly(ethylene glycol) diacrylate hydrogel, facilitating long-term sustainable filmwise condensation. Employing quantitative optical clarity measurements and visualization, we show that our approach clearly outperforms state-of-the-art antifogging alternatives, retaining high optical clarity even in boiling environments. Facile fabrication and superior performance establish our microstructured hydrogel as an excellent choice for sustaining transparency under extreme condensation.