Wetting and Microfluidic Flow of Liquid Crystal Droplets

液晶（lc）是一种介于简单液体和固体晶体之间的材料。它们通常被称为物质的第四种状态，并因其调制可见光的独特能力而引发了一场技术革命。随着新领域的不断涌现，技术应用的潜力远未枯竭，例如基于lc的集成芯片实验室设备，微和光流体系统以及生物传感器。在这个项目中，我们想要研究接近功能表面和微米大小的流动几何形状的液晶液滴的流动和润湿行为。它将由斯特拉斯克莱德大学物理系和数学与统计系合作进行，并结合使用计算方法，如流体动力学的晶格-玻尔兹曼方法和自由能泛函数方法，以及分析理论，如莱斯利-埃里克森框架。从液晶物理的基本观点来看，结果将是有趣的，但也与喷墨打印工艺高度相关，这将成为下一代液晶显示器新制造方法的基石。一些关键的研究方向包括飞行液滴或悬浮液滴的拓扑缺陷研究，这是当前液晶研究的一个非常活跃的领域，但其对流动和润湿行为的依赖完全没有被探索。其他方向包括液滴对功能基板的影响、缺陷的飞行退火以及液滴的平衡形状和有序结构M. Urbanski， C.G. Reyes， J.H. Noh， A. Sharma， Y. Geng， V.S. Jampani和J.P. Lagerwall， J. Phys。提供者。物质29,133003 (2017).[10张建军，李建军，张建军，张建军，张建军，张建军，张建军，张建军，张建军，张建军，张建军，张建军，张建军，张建军P.G. de Gennes， J. Prost，《液晶物理学》，牛津大学出版社，2002年第2版。

Liquid crystals (LCs) are fascinating materials as they feature properties between those of simple liquids and solid crystals. They have been often referred to as the fourth state of matter and ushered in a technological revolution due to their unique capability of modulating visible light. The potential for technological applications is far from being exhausted as new areas emerge constantly, such as LC-based integrated lab-on-a-chip devices, micro- and optofluidic systems as well as biosensors.In this project we want to investigate the flow and wetting behaviour of liquid crystalline droplets [1] close to functional surfaces and in micrometre-sized flow geometries. It will be carried out in a collaboration between the Department of Physics and the Department of Mathematics and Statistics at the University of Strathclyde and use a combination of computational methods such as the lattice-Boltzmann method for fluid dynamics and free energy functional methods [2] and analytical theory like the Leslie-Ericksen framework [3]. The outcome will be interesting from a fundamental point of view of liquid crystal physics, but be also highly relevant for ink-jet printing processes that will form a cornerstone of new manufacturing methods for the next generation of liquid crystal displays.Some of the key research directions include the study of topological defects in droplets in flight or in suspended droplets, a very active field of current liquid crystal research, but entirely unexplored in its dependence of flow and wetting behaviour. Other directions comprise the impact of droplets on functional substrates and the in-flight annealing of defects as well as the equilibrium shape and order structure of droplets.[1] M. Urbanski, C.G. Reyes, J.H. Noh, A. Sharma, Y. Geng, V.S. Jampani and J.P. Lagerwall, J. Phys. Condens. Matter 29, 133003 (2017).[2] K. Stratford, O. Henrich, J. Lintuvuori, D. Marenduzzo, M.E. Cates, Self-Assembly of Colloid- Cholesteric Composites: A Route to Switchable Optical Materials, Nat. Comm. 5, 3954 (2014).[3] P.G. de Gennes, J. Prost, The Physics of Liquid Crystals, Oxford University Press, 2nd editon (2002).