Mork Family Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California 90089, United States.
ACS Appl Mater Interfaces. 2013 Dec 11;5(23):12701-7. doi: 10.1021/am404049x. Epub 2013 Nov 27.
In this study, we demonstrate for the first time the ability to pattern lipophobic fluoropolymer barriers for the incorporation of pure organic solvents as operating liquids within paper-based microfluidic devices. Our fabrication method involves replacing traditional wax barriers with fluoropolymer coatings by combining initiated chemical vapor deposition with inhibiting transition metal salt to pattern the polymer. Multiple techniques for patterning the transition metal salt are tested including painting, spray coating, and selective wetting through the use of a photoresist. The efficacy of the barrier coatings to contain organic solvents is found to be dependent on the conformality of the polymer deposited around the paper fibers. We demonstrate examples of the benefits provided by the containment of organic solvents in paper-based microfluidic applications including the ability to tune the separation of analytes by varying the operating solvent and by modifying the channel region of the devices with additional polymer coatings. The work exhibited in this paper has the potential to significantly expand the applications of paper-based microfluidics to include detection of water insoluble analytes. Additionally, the generality of the patterning process allows this technique to be extended to other applications that may require the use of patterned hydrophobic and lipophobic regions, such as biosensing, chemical detection, and optics.
在这项研究中，我们首次展示了在基于纸张的微流控设备中，通过图案化疏油氟聚合物屏障来引入纯有机溶剂作为工作液体的能力。我们的制造方法涉及通过将引发化学气相沉积与抑制过渡金属盐相结合来替代传统的蜡屏障，从而对聚合物进行图案化。我们测试了多种图案化过渡金属盐的方法，包括绘画、喷涂和通过使用光致抗蚀剂进行选择性润湿。发现屏障涂层对有机溶剂的容纳效果取决于沉积在纸张纤维周围的聚合物的一致性。我们展示了在基于纸张的微流控应用中包含有机溶剂所提供的益处的示例，包括通过改变工作溶剂和通过用附加聚合物涂层修饰设备的通道区域来调整分析物的分离能力。本文展示的工作有可能显著扩展基于纸张的微流控技术的应用范围，包括检测不溶于水的分析物。此外，图案化过程的通用性允许将该技术扩展到其他可能需要使用图案化疏油和疏脂区域的应用，例如生物传感、化学检测和光学。
