School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, P. R. China.
School of Automotive Engineering, Changshu Institute of Technology, No. 99 Hushan Road, Changshu, Suzhou 215500, P. R. China.
Langmuir. 2021 Nov 23;37(46):13703-13711. doi: 10.1021/acs.langmuir.1c02368. Epub 2021 Nov 12.
Fog collection plays an important role in alleviating the global water shortage. Despite great progress in creating bionic surfaces to collect fog, water droplets still could adhere to the microscale hydrophilic region and reach the thermodynamic stable state before falling, which delays the transport of water and hinders the continuous fog collection. Inspired by lotus leaves and cactuses, we designed a Janus membrane that functions to both collect fog from the air and transport it to a certain region. The Janus membrane with opposite wettability contains conical microcolumns with a wettability gradient and hydrophilic copper mesh surface. The apexes of conical microcolumns are superhydrophobic and the rest are hydrophobic. The fog droplets were deposited, coalesced, and directionally transported to the bottom of the conical microcolumns. Then, the droplets unidirectionally passed through the membrane and flowed into the water film on the surface of the copper mesh. The asymmetric structural and wettability merits endow the Janus membrane with an improved fog collection of ∼7.05 g/cm/h. The study is valuable for designing and developing fluid control equipment in fog collection, liquid manipulation, and microfluidics.
集雾在缓解全球水资源短缺方面发挥着重要作用。尽管在创造仿生表面集雾方面取得了很大进展，但液滴仍会附着在微尺度亲水区域，并在下落前达到热力学稳定状态，这会延迟水的传输并阻碍连续集雾。受荷叶和仙人掌的启发，我们设计了一种 Janus 膜，它既能从空气中集雾，又能将雾输送到特定区域。具有相反润湿性的 Janus 膜包含具有润湿性梯度的锥形微柱和亲水铜网表面。锥形微柱的顶点是超疏水的，其余部分是疏水的。雾滴在那里沉积、合并，并定向运输到锥形微柱的底部。然后，液滴单向穿过薄膜，流入铜网表面上的水膜。不对称的结构和润湿性优势使 Janus 膜的集雾效率提高到约 7.05 g/cm/h。该研究对于设计和开发集雾、液体处理和微流控领域的流体控制设备具有重要价值。
