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论文类型：期刊论文

发表时间：2016-02-10

发表刊物：ACS APPLIED MATERIALS & INTERFACES

收录刊物：SCIE、EI、PubMed

卷号：8

期号：5

页面范围：2942-2949

ISSN号：1944-8244

关键字：underwater spontaneous pumpless transportation; extreme wettability patterns; nonpolar organic liquids; cold plasma; superoleophobic surface

摘要：Spontaneous pumpless transportation (SPT) of liquids has generated tremendous demands in microfluidic systems and advanced devices. However, the transportation of nonpolar organic liquids on open platforms underwater remains a challenge because most existing SPT systems are only designed for use in air. Here, we report a surface-tension driven SPT system to transport various nonpolar organic liquids using underwater extreme wettability patterns. The patterns were fabricated with a wedge-shaped superoleophilic track on a superoleophobic background by combining CuCl2 etching, stearic acid modification, and mask-based nitrogen cold plasma treatment. Three types of underwater SPT processes horizontal transport, tilted transport, and directional transport were studied experimentally and theoretically. For horizontal SPT and tilted SPT, the capillary force was the main driving force, which depended on the wedge angle of the superoleophilic track. The excellent transportation ability of horizontal SPT of underwater liquid droplets was obtained at a wedge angle of 3-5. The maximum moving height of organic liquids on the tilted SPT transport was obtained at an angle of 8. For directional SPT, organic liquids did not drop off in the moving process because of the constraint imposed by surface tension, resulting in the sustained directional transport with long distances and complex trajectories.