Water harvesting through the condensation of vapor in air has the potential to alleviate water scarcity in arid regions around the globe. When water vapor is condensed on a cooled surface, tiny water droplets act as thermal barriers. Thus, they must be removed rapidly for efficient water harvesting. Passive technologies for droplet removal rely on in-site growth and direct contact of densely distributed droplets. However, it is challenging to remove submicrometer droplets that lead to a poor water harvesting rate. Here, we present a coarsening effect to rapidly remove water droplets with diameters <20 μm from the hydrophilic slippery liquid-infused porous surface (SLIPS). We quantitatively study the driving and drag forces to enhance the rapid droplet size evolution. The self-propelled coarsening effect enables rapid droplet removal regardless of surface orientations, showing a promising approach compared to those on PEGylated hydrophilic surface, hydrophobic SLIPS, and superhydrophobic surface in water harvesting.

通过空气中的蒸汽冷凝而收集的水具有缓解全球干旱地区缺水的潜力。当水蒸气在冷却的表面上冷凝时，微小的水滴会充当热障。因此，必须迅速将它们去除以有效地进行水收集。去除液滴的被动技术依赖于现场生长以及密集分布的液滴的直接接触。然而，去除亚微米的液滴是有挑战性的，这导致较差的集水率。在这里，我们提出了一种粗化效果，以从亲水滑液注入的多孔表面（SLIPS）中快速去除直径<20μm的水滴。我们定量研究驱动力和阻力，以增强液滴尺寸的快速演变。