界面张力诱导下的微结构内液滴生成和流动控制研究

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, whose capabilities are subjected to the liquid flow rate. Highlighting the dominance of the interfacial tension on droplet flow characteristics, which can reduce effects of the flow rate and finally expand the suitable driving methods of the microdroplet techniques. Based on the interfacial tension induced microfluidics, this project will systematically study the surface evolution and flow characteristics, which result from the Laplace pressure jump of the confined droplet incorporated by the geometry, during the droplet generation and flow controls including the path selection, droplet trapping and on-demand releasing. The relation of flow rates and droplet sizes will be investigated to achieve a weakly dependent droplet emerging geometry. In parallel, the performance of the multi-branch channel will be documented, which originate from the Laplace pressure jump. To expand the suitable flow condition of the microdroplet techniques, a microfluidic system with modules of the droplet generation, trapping and releasing will be studied, which can stably work under various driving approaches. Results of this project will enrich the researches induced by the interfacial tension and offer a deeper understanding of the dependence of the surface applied forces and the droplet behaviors.

液滴微流控技术因其低耗、高效和封闭等优点被广泛关注，其性能受两相流动速度的影响显著。降低液体流动速度对流动特性的影响，突出界面张力的作用，可以使液滴微流控芯片适用于不同类型的驱动方式。本项目基于界面张力诱导下的液滴微流控技术，针对微液滴生成和流动中支路选择、停留和按需释放的控制过程，研究几何受限不平衡所引起的拉普拉斯压力差对两相界面变化和液体流动的影响。分析液体流动速度与微液滴生成尺寸之间的关系，得到流动速度对液滴尺寸影响相对较小的微液滴生成结构；探究多支路结构中，拉普拉斯压力差对液滴流动状态的作用规律；设计一种适用速度范围较大的微流控系统，实现微液滴的稳定生成、停留和按需释放，并且在不同的驱动方式下仍然能够稳定地发挥功能。本项目将丰富界面张力诱导下的微液滴生成和控制方式的研究成果，深化对微液滴界面受力与流动行为之间关系的认识。

本项目基于几何结构与液滴界面的相互作用，研究其所产生的影响液滴运动和变形状态的作用力，并分析其在微液滴生成和流动中支路选择等的控制过程中的作用，以实现降低微液滴的生成和运动控制对驱动速度的依赖性。重点研究了几何受限不平衡所引起的拉普拉斯压力差对两相界面变化和液体流动的影响。分析了液滴生成中几何结构、液体流动速度与微液滴生成尺寸之间的关系，得到了流动速度对液滴尺寸影响相对较小的微液滴生成结构，实现了液滴的稳定生成；研究了多支路结构中，拉普拉斯压力差对液滴流动状态的作用规律，分析了界面张力在液滴运动控制方面的作用形式和作用范围，实现了在变动的速度范围内受限通道中微液滴的运动控制。本项目丰富了微液滴生成和控制方式的研究成果，有助于深化对微液滴界面受力与流动行为之间关系的相关研究。