Effects of surface properties on droplet dynamics in digital microfluidic systems

微流体学，顾名思义，是研究非常小体积流体的行为。微流体的应用可以在用于生化分析的生物技术芯片实验室、用于清洁和高效能源的燃料电池以及用于电子设备的微型热交换器中找到。近年来，液滴作为化学和生化反应的最小反应器被认为是新一代微流控技术，即数字微流控技术。在这类用于生物和生化分析的系统中，界面张力和表面润湿性通常用于流量计量、激活和控制。由于高的表面积体积比，在数字微流体中必须仔细考虑微观固流相互作用和相关的界面现象。然而，定量信息仍然不足，因此继续阻碍相关的工程应用。

Microfluidics, by name, studies the behaviors of fluids of very small volumes. Applications of microfluidics can be found in biotech lab-on-a-chips for biochemical analysis, fuel cells for clean and efficient energy, and micro heat exchangers for electronics. Recently, liquid droplets, which can function as the smallest reactors in chemical and biochemical reactions, are considered as the next generation microfluidic technology, or the so-called digital microfluidics. In such systems for biological and biochemical analysis, interfacial tension and surface wettability are usually employed for flow metering, activation, and control. Due to the high surface-area-to-volume ratio, microscopic solid-fluid interactions and related interfacial phenomena have to be considered carefully in digital microfluidics. However, quantitative information is still inadequate and hence continues to hinder relevant engineering applications.