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材料，以防止腐蚀或提供特殊的表面性能。一种常见的涂层方法是在表面喷洒一种液体。涂层的有效性和弹性通常取决于复杂的细节，即液滴如何影响表面反弹、飞溅并在表面上扩散形成涂层。尽管经过了几十年的研究和实践，但人们对涂层工艺的基本原理，特别是在具有复杂形状的产品和机器上的基础还没有完全了解。这个GOALI项目是伊利诺伊大学芝加哥分校(UIC)和喷涂系统公司共同努力的结果，目的是进行实验和开发数值模拟，以确定是否可以通过施加电场来控制液滴撞击表面时的液滴动力学细节来改进涂层工艺。在UIC进行的基础研究的结果将被用于制定喷雾方案，并将在喷雾系统在工业相关条件下进行测试。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，以吸引所有学术水平的学生，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。该GALI项目的目标是研究电场存在下的液滴动力学，以操纵喷涂过程。该项目将专注于液滴在附着在产生电场的电极上的衬底上的撞击、沉积和传播。将进行实验，分析液滴在介电和导电表面上的碰撞和传播，以评估液滴的形状和传播差异。将评估表面形貌对液滴过程的影响。用从头算密度泛函理论计算液滴撞击介电表面和导电表面的相场模型，得到表面结合能。结果将用于开发喷洒方案，并将在喷洒系统的实践中进行测试。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.