同轴流动下双乳液滴的生成机理及控比分裂特性研究

液滴微流控技术因其低耗、高效和封闭等优点被广泛关注，双乳液滴独特的核-壳结构能够有效保护内核中的反应物，也为多组分液滴的精准操控提供了重要载体。双乳液滴的尺寸和生成通量是应用中的重要参数，目前主要依靠生成过程进行调节，作用范围局限性大并且调节机理欠缺系统分析。本项目基于同轴流动型的双乳液滴生成技术，针对双乳液滴生成和流动中的分裂过程，研究界面剪切变形和几何受限不平衡所引起的受力变化对界面破裂和液体流动状态的影响。分析液体流场与双乳液滴生成尺寸之间的关系，得到双乳液滴不同生成模式的临界条件；探究对称结构中，双乳液滴对称分裂的界面受力变化过程以及分裂条件；分析不对称分裂的影响因素，设计分裂比可控的微流控芯片，实现双乳液滴的可控、稳定分裂，并且在较大流量范围内仍然能够稳定地发挥功能。本项目将深化双乳液滴生成的理论研究，扩大双乳液滴性能的可控性并提高其应用性能。

The droplet-based microfluidic technique has attracted widespread interest, attributed to the advantages such as a small volume of reagents consumed, the fast reaction and the independent control of each droplet. Among them, the unique core - shell structure of double emulsion droplets can effectively protect the reaction products in the core and provide an important carrier for the precise handling of multi-component droplets. The size and throughput of the emulsion droplets are important parameters in the application that are mainly regulated by the generation process at present, while the scope of manipulation is limited and the systematic analysis of the adjustment mechanism is lacked. In view of the double emulsion droplet generation and splitting during the flow process, the influence of the stress variation on the interfacial rupture and liquid flow state caused by the shear-induced surface evolution and the geometry confined unbalance will be studied by this project, based on the co-flow type of double emulsion droplet generation technology. The relationship between the flow field and the size of the droplets will be analyzed to obtain the critical conditions for different formation modes. The change of interfacial forces and the splitting conditions of the double emulsion droplets will be investigated in the symmetrical structure. The influencing factors of asymmetric splitting will be analyzed and the microfluidic chip with desired splitting ratio will be designed to achieve controllable and stable splitting of double-emulsion droplets, which can still play a stable role within a large range of flow rate. This project will deepen the theoretical study of the generation of double emulsion droplets, and expand the performance of controllability and application of the double emulsion droplets as well.