面向微反应器的液体弹珠电操控的研究

液体弹珠指于空气中被疏水颗粒包裹形成的液滴。其具有体积小、制备简便、不润湿基底的特性，是一种理想的微反应器载体，并在微化学反应、生物医学检测等领域具有良好的应用前景。但目前液体弹珠的操控尚停留在单液滴层面，难以满足很多应用中的高通量需求。电场力方法有望利用可编程、可动态配置的电极系统来实现液体弹珠的高频操控。但液体弹珠的电响应特性复杂，交流电场对其电操控行为尚待进一步研究。针对以上问题，申请者将探讨液体弹珠的稳定性规律和机理，提出增强弹珠机械稳定性和抑制其蒸发过程的方法；构建交流电操控系统，对液体弹珠的电聚并现象进行系统考察和表征，并揭示交流电场触发电聚并的物理机理；利用感应电场力驱动液体弹珠内液体的对流，实现物质的快速、有效混合。并基于液体弹珠微反应器内开展化学反应，验证电混合的有效性。该研究将为实现液体弹珠的高通量电操控奠定实验和理论基础，从而推进液体弹珠在微反应器应用领域的发展。

Liquid marbles are droplets in air stabilized by non-wetting particles. They are millimeters in size, easy to be fabricated and non-steaky to substrates, which endows liquid marbles great potential as ideal micro-reactors for various applications such as chemical reactions, biomedical process and immunoassay. However, current manipulation of liquid marbles is on single-droplet scale which limits their potential in applications that demand high throughput operations. Electric manipulation of liquid marbles could take the advantage of arrays of surface electrodes that can be reconfigured in a computer software, and can significantly increase the operation frequency. However, the responses of liquid marble in an AC electric field still need to be explored explicitly. In this work, we will first investigate the liquid marbles’ mechanical stability and evaporation rate, aiming to propose a feasible approach to improve the mechanical stability of liquid marble as well as to prevent its evaporation rate. Afterwards, we will build an experiment system utilizing the AC electric field to study the electric manipulation of liquid marble. We will apply an electric stress to trigger the electro-coalescence of liquid marbles. A theoretical model will also be explored to explain the physics behind the electro-coalescence. Finally, we will study how the electric stress induce the fluid convection within liquid marbles and mix the contents efficiently and rapidly. Using the liquid marbles as the micro-reactors, we will also carry out chemical reactions and verify the effectiveness of the electric mixing. This work could provide the both experimental and theoretical guidelines for high-throughput electrical manipulation of liquid marbles, and thus promote the development of liquid marbles as microreactors for various applications.