胶体液滴蒸发中多物理效应协同下的颗粒输运动力学跨尺度研究

Over the last two decades, there has been a surge of scientific interest in the transport and deposition of particles in an evaporating colloidal droplet, not only because the evaporation process involves multiple physical phenomena, but because the process influences a wide range of applications such as inkjet printing, photonic crystal formation, disease diagnosis, etc. However, the particle transport dynamics in drying droplet is still imperfect, and the critical problem lies in the lack of comprehensive and systematic understanding about competition and cooperation mechanisms of multiple physical effects from macro- to micro-level, which has greatly limited its application. By combining theories and experiment, this project is proposed to study the spatiotemporal evolution and correlation of the macroscopic shape and microscopic particles during droplet evaporation by utilizing cross-scale analysis and visualization method. A macro-microscopic coupled mechanics-physics model of interfacial particle transport is established. Further more, this project intends to explore the particle transport mechanism under the cooperation and competition of various physical effects. Based on the above fundamental study, prediction and control of deposition pattern is expected to be implemented, which is capable of developing new functional microstructures and the related materials.

在过去的二十几年里，胶体液滴蒸发中的颗粒输运和沉积引起了科研人员极大的研究兴趣，这既因为蒸发过程中蕴含着丰富的物理学现象，又由于其在喷墨打印、光子晶体制备、疾病诊断等领域展现出广阔的应用前景。然而，关于蒸发液滴中的颗粒输运动力学理论仍然不完善，关键问题在于对跨（宏-微观）尺度层次下多物理效应的协同和竞争关系缺乏全面系统的理解，这大大限制了其应用。本项目拟利用实验和理论相结合的方法，对蒸发过程中液滴宏观形状和微观颗粒的时空演化规律和关联性开展跨尺度可视化研究，建立宏微观耦合的界面颗粒输运物理力学模型，探索多种物理效应协同和竞争下的颗粒输运机制，并基于上述机理开展沉积图案的调控，发展制备新型微纳功能材料的新方法。

本项目以胶体液滴系统为研究对象，针对液滴蒸发中的复杂粒子输运行为和沉积图案精确调控难题，对液滴宏观形状和微观粒子输运的时空演化过程开展了跨尺度可视化研究，研究内容包括：1）揭示了宏微观耦合下多物理效应的协同竞争作用决定粒子输运行为；2）建立了气液界面减压强化蒸发模型，基于界面捕获实现胶体粒子快速组装；3）引入纳米渗吸作用，实现胶体晶体的超快自组装和沉积图案的有效调控；4）将胶体自组装与直写打印结合，实现胶体序构的跨尺度制造。本项目开展的液滴蒸发与胶体自组装研究，有望为喷墨打印、光子晶体超材料、液滴生化检测等应用提供重要理论和方法支持。