Characterization of non-Newtonian fluids at small length scales

流体在毫米及以下的长度尺度上表现出高度粘性的行为，而由于这些材料的复杂性质，它们的流动可能非常复杂。在自然界、生物体、制造业以及环境和生物医学设备中，存在着许多这样小长度尺度的流动。我的研究计划旨在增加我们对小尺度复杂流动行为的理解，以开发新的生产方法，以及设计有效的设备概念，在生命科学，自然资源和印刷领域具有重要应用。该基金支持本研究计划中涉及两类流动问题的几个项目的研究：(1)在高温下可逆固化的热响应流体的流动；(2)聚合物的溶剂铸造。这两个领域的研究将受益于我的实验室开发的先进成像和流动表征方法。***我们将展示基于这些热响应流体的智能阀门的几个概念，用于生物医学和环境监测设备。我们还将热响应流体沉积在透明的加热表面上，以阐明液滴在表面上的凝固机制，这在相关的不透明流体中很难观察到，例如熔融食品（即巧克力）和熔融金属。此外，我们将测量盐的存在如何影响热响应流体的凝固，以及研究这些流体在类似于油藏岩石孔隙的小通道中的流动。我们将评估这些生物相容性液体是否适合提高采收率，并开发使用后去除这些液体的方法。***在聚合物溶液的溶剂铸造中，溶剂蒸发后在模具上留下聚合物涂层。该工艺允许制造微结构设备，如用于生物医学应用的微针。当溶剂蒸发时，我们将描述这些聚合物溶液中的流动，以预测聚合物在模具上的沉积剖面，以及设计适当的材料和优化工艺条件。我们将把我们对溶剂铸造过程中流动现象的理解应用到溶剂铸造过程中电子芯片的集成中。这将最终导致廉价的高性能生物医学和环境设备和系统，用于快速检测化合物。***在整个研究项目中，对小尺度非牛顿流体的表征将导致我们对小尺度流体力学的理解取得重大突破，使新技术能够改善加拿大人的生活和环境，对加拿大的经济产生积极影响。*****

Fluids show highly viscous behaviour at length scales of millimetres and below, while the flow of these materials can be highly complex due to their complex properties. Flows at such small length scales exist with many examples in nature, living organisms, manufacturing, and environmental and biomedical devices. My research program aims at increasing our understanding of this complex flow behaviour at small length scales in order to develop new production methods, as well as to design effective device concepts with important applications in life sciences, natural resources, and printing. This grant supports research on several projects within this research program involving two types of flow problems: (1) the flow of thermally responsive fluids that can solidify reversibly at elevated temperatures and (2) solvent casting of polymers. Research in both areas will benefit from the advanced imaging and flow characterization methods developed in my lab.***We will demonstrate several concepts of smart valves based on these thermally responsive fluids for applications in biomedical and environmental monitoring devices. We will also deposit thermally responsive fluids onto transparent heated surfaces to elucidate the solidification mechanics of drops on surfaces, which is difficult to observe in relevant opaque fluids such as molten food stuff (i.e. chocolate) and molten metal. Further, we will measure how the presence of salts can affect the solidification of thermally responsive fluids, as well as investigate the flow of these fluids in small channels comparable to the pores of rock in oil reservoirs. We will assess whether these biocompatible fluids are suitable for enhanced oil recovery and also develop methods to remove these fluids after use.***In solvent casting of polymer solutions, the solvent evaporates leaving a polymer coating on the mould. This process allows the fabrication of microstructured devices such as microneedles for biomedical applications. We will characterize the flow within these polymer solutions as the solvent evaporates to predict the polymer deposition profile on the moulds, as well as design adequate materials and optimize process conditions. We will apply our understanding of the flow phenomena during solvent casting to the integration of electronic chips during the solvent casting process. This will eventually lead to inexpensive high-performance biomedical and environmental devices and systems for the rapid detection of compounds.***The characterization of non-Newtonian fluids at small length scales throughout this research program will lead to significant breakthroughs in our understanding of small-scale fluid mechanics enabling new technologies to improve the lives of Canadians and the environment with a positive impact on Canada's economy.*****