Anti-shrinkage Rigid Macroporous Hydrogel with Dual Osmotic-Capillary Pumping for Ultra-Fast Atmospheric Water...

Hygroscopic hydrogels are promising materials for high-efficiency sorption-based atmospheric water harvesting (SAWH); however, their practical application is constrained by intrinsically slow water transport within the collapsed dehydrated polymer networks, a process predominantly governed by osmotic pressure gradient (∇π_os). Here, we develop a rigid-polymer-network-based interconnected macroporous hygroscopic hydrogel (H_RIMP) via a facile foaming-assisted polyelectrolyte diffusion-complexation strategy, enabling ultrafast sorption/desorption kinetics for high-efficiency SAWH. The antishrinkage rigid network resists structural collapse during dehydration, preserving a hierarchical porous architecture that synergistically combines ∇π_os with capillary pumping to accelerate water transport beyond the limitations of conventional hydrogels. Consequently, the H_RIMP exhibits excellent sorption/desorption kinetics across a wide humidity range, achieving equilibrium water uptake within just 45 and 90 min at 30% and 90% relative humidity (RH), respectively, and releasing 83.4% of adsorbed water within only 29.5 min under one sun irradiation. Leveraging this ultrafast kinetics, we design a continuous cyclic SAWH device that maintains high water productivity (1.07 L_water kg_sorbents^-1 day^-1) even under cold, dry winter conditions (around 0 °C, 43% RH). This rigid-network design strategy provides a generalizable approach to overcome the inherent mass-transfer limitations of gel-based adsorbents, promoting the practical application of high-performance SAWH systems.