Department of Electronics and Electrical Engineering, University of Glasgow, G12 8LT, United Kingdom.
Langmuir. 2010 Sep 21;26(18):14443-9. doi: 10.1021/la101517t.
Electrocoalescence of water-in-oil microdroplets in microfluidic channels is an active technique that enables droplet-based mixing functionalities to be achieved in lab-on-a-chip applications. In this work, a characterization of the electrocoalescence mechanisms of water microdroplets in oil is presented, using localized electric field systems. We report a theoretical and experimental description of the electrocoalscence behavior of droplet pairs by varying the physical and fluid dynamic conditions of the phases. Our results demonstrate that localized electric field systems can be reliably used to merge droplets in pairs, regardless of the distance between the drops. The coalescence behavior was dependent upon the viscosity of the continuous phase for water droplets that were separated by a thick layer of oil and upon interfacial tension for droplets that were in close proximity. We showed that these systems have the potential to be used for high-throughput applications and that, unlike other examples of active systems in the literature, the need of droplet synchronization and the application of high voltages is considerably reduced.
在微流控通道中，油包水乳状液滴的电聚并是一种主动技术，可实现微流控芯片应用中的基于液滴的混合功能。在这项工作中，我们使用局部电场系统对油中微小水滴的电聚并机制进行了表征。通过改变各相的物理和流体动力学条件，我们报告了液滴对电聚并行为的理论和实验描述。我们的结果表明，无论液滴之间的距离如何，局部电场系统都可以可靠地用于合并液滴对。聚并行为取决于被厚油层隔开的水相的粘度，以及接近的液滴的界面张力。我们表明，这些系统有可能用于高通量应用，与文献中其他主动系统的示例不同，不需要液滴同步和施加高电压。
