Future Conversion Technology Research Division, Korea Institute of Science and Technology, Seoul, 130-650, Korea.
Nanoscale. 2012 Apr 28;4(9):2900-5. doi: 10.1039/c2nr11934j. Epub 2012 Mar 29.
The exterior structures of natural organisms have continuously evolved by controlling wettability, such as the Namib Desert beetle, whose back has hydrophilic/hydrophobic contrast for water harvesting by mist condensation in dry desert environments, and some plant leaves that have hierarchical micro/nanostructures to collect or repel liquid water. In this work, we have provided a method for wettability contrast on alloy steels by both nano-flake or needle patterns and tuning of the surface energy. Steels were provided with hierarchical micro/nanostructures of Fe oxides by fluorination and by a subsequent catalytic reaction of fluorine ions on the steel surfaces in water. A hydrophobic material was deposited on the structured surfaces, rendering superhydrophobicity. Plasma oxidization induces the formation of superhydrophilic surfaces on selective regions surrounded by superhydrophobic surfaces. We show that wettability contrast surfaces align liquid water within patterned hydrophilic regions during the condensation process. Furthermore, this method could have a greater potential to align other liquids or living cells.
自然界生物体的外部结构通过控制润湿性不断进化，例如纳米布沙漠甲虫，其背部具有亲水性/疏水性对比，可通过雾冷凝在干燥的沙漠环境中收集水分，还有一些植物叶片具有分级的微/纳结构，可收集或排斥液态水。在这项工作中，我们提供了一种在合金钢上实现润湿性对比的方法，包括纳米薄片或针状图案和表面能的调节。通过氟化和随后在水中钢表面上氟离子的催化反应，在钢上形成了 Fe 氧化物的分级微/纳结构。在结构化表面上沉积疏水性材料，使其具有超疏水性。等离子氧化在超疏水表面包围的选择性区域上诱导形成超亲水表面。我们表明，在冷凝过程中，润湿性对比表面可在图案化亲水区域内对齐液态水。此外，该方法有可能更好地对齐其他液体或活细胞。
