GOALI: Collaborative Research: Non-invasive measurement of kinematics and rheology in a non-equilibrium drying complex fluid

涂料影响许多应用，包括消费品、医药、食品和工程应用，通常用于三个目的之一：保护和延长产品的寿命、改善美观或增加新功能。流体薄膜涂层在固化过程中形成的微小缺陷可能会损害涂层的最终功能。在一家汽车工厂，喷漆占能源消耗的60%，修复缺陷的翻新成本可能超过1000万美元/年。很少有方法能够在干燥过程中非侵入性地跟踪涂层特性。该项目的目标是开发利用时间和空间分辨率的光学测量来测量干燥涂层的瞬时粘度和流动的能力。通过该项目获得的有关瞬变流变学如何影响流体流动的基本知识将适用于多种涂层制造工艺。该项目将对涂料的设计和加工产生重大影响，有助于弥合学术界和工业界之间的差距，并将延伸到科学、技术、工程和数学界。该计划的研究目标是测量干燥复杂流体的瞬时流变学和运动学。传统的宏观流变学技术需要在测量过程中与涂层进行物理接触(即，该技术是侵入性的，并改变干燥)，并且无法在空间上解决涂层内的流变性变化。该项目将通过非侵入性、高时间和空间分辨率的光学技术来测量模型复杂流体中的时间和空间分辨的流变性和流动。具体地说，研究目标是：(1)测量变粘度干燥薄膜的流变性的空间相关性；(2)确定并实施适用于干燥粘弹性流体薄膜的对流修正方法；(3)测量配方和衬底角度对干燥粘弹性流体薄膜中瞬时对流胞结构和相关微结构形成的影响。拟议的~0.100 mm薄膜模型的工作将适用于一系列广泛的应用，并将补充工业合作伙伴PPG正在进行的工作。如果成功，这项研究将极大地提高涂料的设计和工艺，适用于广泛的应用。这一奖项反映了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。

Coatings impact many applications, including consumer products, medicine, food, and engineering applications, typically serve one of three purposes: to protect and extend the life of a product, to improve aesthetics, or to add new functionality. Small defects that form during solidification of a fluid film coating can harm the ultimate functionality of the coating. In a single automotive plant, painting accounts for 60% of the energy consumption, and refinishing to repair defects can cost more than $10 million/year. There are few methods capable of non-invasive tracking of the coating properties during drying. The objective of this project is to develop the capability to measure the transient viscosity and flow of a drying coating with time- and space- resolved optical measurements. The underlying knowledge gained via this project in relation to how transient rheology affects fluid flow will be applicable to a multitude of coating manufacturing processes. The project will have significant impact on coatings design and processing, help to bridge the gap between academia and industry, and include outreach to the science, technology, engineering, and math communities.The research objective of this proposal is to measure the transient rheology and kinematics of a drying complex fluid. Traditional macroscopic rheological techniques require physical contact with the coating during the measurement (i.e. the technique is invasive and alters drying) and are unable to spatially resolve rheological changes within the coating. This project will be enabled by non-invasive, high temporal and spatial resolution optical techniques to measure the time- and space-resolved rheology and flow in model complex fluids. Specifically, the research goals are to (1) measure the spatial dependence of rheology in a drying thin film with varied viscosity, (2) to determine and implement a suitable method of convection correction for thin films of drying viscoelastic fluids, and (3) to measure the impact of formulation and substrate angle on the transient convection cell structure and related microstructure formation in thin films of drying viscoelastic fluids. The proposed work on model ~0.100 mm thin films will be applicable to a broad set of applications and will complement ongoing work the industrial partner, PPG. When successful, this research will significantly enhance the design and processing of coatings for a wide range of applications.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.