Easy Route to Superhydrophobic Copper-Based Wire-Guided Droplet Microfluidic Systems
Easy Route to Superhydrophobic Copper-Based Wire-Guided Droplet Microfluidic Systems
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DOI：
10.1021/nn900607p
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发表时间：
2009-09-01
期刊：
影响因子：
17.1
通讯作者：
Sikorski, Pawel
中科院分区：
文献类型：
--
作者：
Mumm, Florian;van Helvoort, Antonius T. J.;Sikorski, Pawel
基于液滴的微流控系统是基于单个液滴的修改和分析的实验室概念向灵活的、可重新配置的设置的扩展。超疏水表面是实现基于液滴的微流体系统的一个合适的候选者，因为水性液体在这种表面上的高流动性提供了使用新颖或更有效的液滴移动方法的可能性。在这里，铜基超疏水表面的产生，通过使用微电子工业中常见的蚀刻剂沿晶界沿着蚀刻多晶铜样品，通过电沉积铜膜，随后基于热氧化的纳米线装饰，或通过两者的组合。表面可以很容易地用硫醇改性的碳氟化合物疏水化，之后产生的表面显示出高达171度+/- 2度的水接触角。由于选择铜作为基础材料，从印刷电路板制造中采用的已建立的图案化技术可以用于在表面上制造宏观结构，目的是限制液滴，从而降低系统对倾斜和振动的敏感性。一个简单的液滴为基础的微流控芯片的入口，出口，样品储存，和混合区。导线引导，一个相对较新的驱动方法适用于超疏水表面上的水性液体，被施加到移动液滴。
Droplet-based microfluidic systems are an expansion of the lab on a (hip concept toward flexible, reconfigurable setups based on the modification and analysis of individual droplets. Superhydrophobic surfaces are one suitable candidate for the realization of droplet-based microfluidic systems as the high mobility of aqueous liquids on such surfaces offers possibilities to use novel or more efficient approaches to droplet movement. Here, copper-based superhydrophobic surfaces were produced either by the etching of polycrystalline copper samples along the grain boundaries using etchants common in the microelectronics industry, by electrodeposition of copper films with subsequent nanowire decoration based on thermal oxidization, or by a combination of both. The surfaces could be easily hydrophobized with thiol-modified fluorocarbons, after which the produced surfaces showed a water contact angle as high as 171 degrees +/- 2 degrees. As copper was chosen as the base material, established patterning techniques adopted from printed circuit board fabrication could be used to fabricate macrostructures on the surfaces with the intention to confine the droplets and, thus, to reduce the system's sensitivity to tilting and vibrations. A simple droplet-based microfluidic chip with inlets, outlets, sample storage, and mixing areas was produced. Wire guidance, a relatively new actuation method applicable to aqueous liquids on superhydrophobic surfaces, was applied to move the droplets.