GOALI: Controlled Coating via Charged Droplet Impact and Deposition on Dielectric and Conducting Surfaces

消费者和工业使用的许多产品都涂有一层又一层的材料，以防止腐蚀或提供特殊的表面性能。一种常用的涂覆方法是在表面喷一种液体。涂层的有效性和弹性通常取决于影响表面的液滴如何反弹，飞溅并在表面上扩散以形成涂层的复杂细节。尽管经过几十年的研究和实践，涂装工艺的基本原理，特别是在复杂形状的产品和机器上，还没有完全理解。GOALI项目由伊利诺伊大学芝加哥分校（UIC）和喷涂系统公司共同开展，旨在通过实验和数值模拟来确定涂层过程是否可以通过施加电场来控制液滴撞击表面时的动力学细节来改进。在UIC进行的基础研究结果将用于制定喷洒方案，并在与工业相关的条件下在喷洒系统上进行测试。UIC的研究团队和喷涂系统公司的代表还将开展一系列外展活动，让各个学术水平的学生，特别是那些来自代表性不足群体的学生参与研究和相关演示。这个GOALI项目的目标是研究电场存在下的滴动力学，以操纵喷涂过程。该项目将重点研究液滴在附着在电极上的基底上的撞击、沉积和扩散，从而产生电场。通过实验分析液滴在介电表面和导电表面的冲击和扩散，评价液滴的形状和扩散差异。将评估表面形貌对液滴过程的影响。液滴撞击介质和导电表面的相场建模将采用从头算密度函数理论计算得到表面结合能。研究结果将用于制定喷洒方案，并在喷洒系统进行实践测试。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Many products used by consumers and industry are coated with layers of materials to prevent corrosion or to provide specialized surface properties. A common way to apply a coating is to spray a liquid onto the surface. The effectiveness and resilience of the coating often depends on intricate details of how the liquid drops that impact the surface bounce, splash, and spread over the surface to form the coating. Despite decades of research and practice, the fundamentals of coating processes, especially on products and machines with complex shapes, are not fully understood. This GOALI project is a joint effort between the University of Illinois - Chicago (UIC) and the Spraying Systems Company to conduct experiments and develop numerical simulations that will determine whether coating processes can be improved by applying an electric field to control details of drop dynamics as the drops impact the surface. The results of fundamental studies conducted at UIC will be used to develop spraying protocols that will be tested at Spraying Systems under industrially relevant conditions. The research team at UIC and representatives from Spraying Systems will also conduct a series of outreach activities to engage students at all academic levels, especially those from underrepresented groups, in the research and related demonstrations.The goal of this GOALI project is to investigate drop dynamics in the presence of an electric field to manipulate spray coating processes. The project will focus on droplet impact, deposition, and spreading on substrates attached to electrodes that generate an electric field. Experiments will be conducted to analyze droplet impact and spreading on dielectric and conducting surfaces to evaluate the droplet's shape and spreading difference. The influence of the morphology of the surface on droplet processes will be evaluated. Phase-field modeling of droplet impact onto dielectric and conducting surfaces will be carried out, using ab initio density function theory calculations to obtain surface binding energies. The results will be used to develops spraying protocols that will be tested in practice at Spraying Systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.