Three-Dimensional Printing of Chitin Nanocrystals/Gelatin Scaffold for Water Harvesting Application

Atmospheric water harvesting (AWH) technology based on adsorption offers a promising solution to freshwater scarcity. Chitin nanocrystals/gelatin composite scaffolds were precisely constructed via direct ink writing (DIW) 3D printing in this study. After polydopamine coating was applied to endow the scaffold with photothermal conversion properties, the scaffold was further impregnated with lithium chloride to introduce hygroscopicity. This process produced a hierarchical porous material for AWH. Compared to traditional aerogels, this 3D-printed scaffold exhibited approximately 59.5% higher water uptake and nearly 1.99 times higher average water sorption rate within 30 min. The scaffold demonstrated stable hygroscopic performance across a broad humidity range (30-90% RH). Under natural outdoor sunlight, the material achieved an average daily water yield of approximately 0.60 g g^-1. This study introduces a structurally controllable, performance-stable hygroscopic salt-based biomacromolecule composite for AWH, demonstrating potential for agricultural applications and environmental sustainability.