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材料层，以防止腐蚀或提供特殊的表面性能。 施加涂层的常见方式是将液体喷射到表面上。 涂层的有效性和弹性通常取决于撞击表面的液滴如何反弹、飞溅和在表面上扩散以形成涂层的复杂细节。 尽管经过数十年的研究和实践，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，尚未完全理解。 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，旨在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液滴动力学的细节来改善涂层工艺。 在UIC进行的基础研究的结果将用于开发喷雾方案，这些方案将在工业相关条件下在喷雾系统进行测试。 UIC的研究团队和Spraying Systems的代表还将开展一系列外展活动，让所有学术水平的学生，特别是那些来自代表性不足的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液滴动力学，以操纵喷涂过程。该项目将重点关注液滴的影响，沉积和附着在电极上的基板上的扩散，这些电极会产生电场。 实验将进行分析液滴的影响和传播的介质和导电表面，以评估液滴的形状和传播的差异。 将评估表面形态对液滴过程的影响。 将进行液滴撞击到电介质和导电表面的相场模拟，使用从头计算密度泛函理论计算以获得表面结合能。 该奖项反映了NSF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.