Department of Electrical Engineering, University of Missouri-Columbia, Columbia, Missouri 65211, USA.
Langmuir. 2013 Jan 29;29(4):994-8. doi: 10.1021/la3040038. Epub 2013 Jan 17.
Manipulating and controlling water-based aqueous solutions with the use of virtual walls is relatively simple compared to that of nonaqueous low-surface-tension liquids, which pose greater challenges to microfluidic devices. This letter reports a novel technique to form a virtual wall for various low-surface-tension liquids. A microfluidic channel with virtual walls has been made to guide low-surface-tension liquids by using a specially designed oil-repellent surface. Unlike generic superoleophobic surfaces, our oil-repellent surface exhibited strong repellency to the lateral flow of low-surface-tension liquids such as hexadecane and dodecane. A plasma-assisted surface micromachining process has been utilized to form the oil-repellent surface. The use of combined features of re-entrant geometries on the surface played an important role in promoting its repellence to the lateral flow of low-surface-tension liquids. We have successfully demonstrated how low-surface-tension liquids can be well confined by the virtual walls.
与非水低表面张力液体相比，使用虚拟墙来操纵和控制水基水溶液相对简单，因为后者对微流控设备构成了更大的挑战。这封信报告了一种用于各种低表面张力液体的形成虚拟墙的新技术。通过使用专门设计的疏油表面，已经制造出具有虚拟壁的微流道来引导低表面张力液体。与通用的超疏油表面不同，我们的疏油表面对低表面张力液体（如十六烷和十二烷）的横向流动表现出很强的排斥性。等离子体辅助的表面微加工工艺已用于形成疏油表面。表面上的凹入几何形状的组合特征在促进其对低表面张力液体的横向流动的排斥性方面发挥了重要作用。我们已经成功地证明了低表面张力液体如何可以通过虚拟壁很好地被限制。
