Microscopic defects are ubiquitous in layered liquids such as smectic liquid crystals and concentrated surfactant solutions. Defects play a leading role in determining the flow behavior of layered liquids; indeed flows and defects are strongly coupled and more defects often form when a sample is sheared. The presence of defects therefore impacts a wide variety of industrial applications including the development of novel applications exploiting the ordered nature of lamellar materials, such as optoelectronic devices and displays, as well as processing of biomaterials to encapsulate drugs, and formulation and processing of coatings, adhesives, pharmaceuticals, and food products. The central problem in optimizing formulation and processing conditions for these applications is that neither theory nor experiment are adequately developed to quantitatively describe the fluid dynamics near flowing defects or the interaction of defects with flows. This project aims to bridge this gap by developing tools to model idealized defects both experimentally and theoretically. The central idea of the research plan is to change the length scale of flow devices in order to enhance control over the defect microstructures. The expected outcomes include the ability to tune the equilibrium defect array structure using geometry and surface anchoring, the development of an experimental phase diagram organizing observed defect microstructures as a function of initial defect configuration, flow strength, and time; comparison of experiments with available theoretical models through scaling and analytics; and finally, a preliminary study extending this work to other layered liquids. The central aim of the education plan is to motivate students to study engineering and help them to develop physical intuition for thermal-fluids concepts through the development of component-based learning instruments, which integrate several interactive learning activities around a central, industrially-relevant example of engineering hardware, e.g. inkjet printing. This approach offers students several perspectives from which to learn fundamental concepts, and it exposes them to emerging technologies. The component-based modules will be implemented across education levels and disciplines, and they will be simplified for K-12 outreach activities targeted toward encouraging participation of underrepresented groups in engineering and science.
Co-funded by the EHR Research on Learning and Education Program.
