Large-Amplitude Oscillatory Shear Flow of Polymeric Liquids

流变学是研究物质的流动和变形的科学。不是简单的物质，如水或空气，而是复杂的物质，如粘稠的弹性液体。这些流体很复杂，因为它们的分子又长又像链状。我的流变学研究是关于将这些长链分子的运动和排列与液体弹性联系起来。我们将通过仔细摇动最新昂贵、复杂、计算机化的流变仪中的聚合物分子来揭示这些联系。在我的探索基金期间以及之后的几年里，我的团队将在被称为大振幅振荡剪切(LAOS)的抖动实验中探索弹性液体的分子结构和它们的流变学之间的关系。 我们之所以关心振动剪切，是因为它是最流行的粘弹性特性测量方法，当在大振幅下进行时，该测试可以揭示复杂液体响应的非线性粘性和弹性部分的丰富的有趣细节。自从我在这个主题上的博士论文[McGill，化学工程(1987)]以来，我的团队一直是老挝聚合物液体表征的领先实验室。 为了加深我们对这些反应的理解，在液体微观结构方面，我的团队现在将注意力转向使用动力学分子理论来探索分子结构和老挝应激反应之间的联系[JCP140,074904(2014年)]。在接下来的五年里，我们的目标是根据振荡剪切流中模型分子的长度来计算聚合物液体的应力响应，并将这些预测与我们的实验测量进行比较。具体地说，我们的目标是在实验室中改变分子结构，并探索其对流变学反应的影响。当将动力学分子理论推广到多分散体系时，会出现一些特殊的问题，因为弛豫谱与麦克斯韦模型不同。在接下来的五年里，我的团队将解决这些特殊的理论问题。 我的新女王实验室将很快配备最新的突破性仪器，用于测量老挝的流变性反应：平板隔板锥板流动。在去年夏天在德国合作完善这项技术后，我设计了这项提案，以利用我的新加拿大流变学研究主席的资源，特别是从相应的CFI资金订购的新设备。我们为博士后和博士后学生寻求发现资助，以通过仔细测量已知分子结构的聚合物液体来评估结构理论的最新进展。

Rheology is the study of the flow and deformation of matter. Not of simple matter, like water or air, but complex matter, like sticky, gooey, elastic liquids. These fluids are complex because their molecules are long and chainlike. My rheological research is all about connecting the motions and alignments of these long chain molecules with liquid elasticity. We will uncover these connections by carefully jiggling the polymer molecules in the latest expensive, sophisticated, computerized instruments called rheometers. Over the period of my Discovery Grant, and for years beyond, my team will explore the relation between the molecular structure of elastic liquids, and their rheology in jiggling experiments called large-amplitude oscillatory shear (LAOS). We care about oscillatory shear because it is the most popular viscoelastic property measurement, and when done at large amplitude, this test can uncover a rich diversity of interesting detail about the nonlinear viscous and elastic parts of a complex liquid response. Since my doctoral thesis on this subject [McGill, Chemical Engineering (1987)], my group has been a leading laboratory on the characterization of polymeric liquids in LAOS. To deepen our understanding of these responses, in terms of the liquid microstructure, my group is now turning its attention to the use of kinetic molecular theory to explore the connections between molecular structure and the stress response in LAOS [JCP, 140, 074904 (2014)]. Over the next five years, we aim to calculate the stress response of the polymeric liquid in terms of the length of the model molecule in oscillatory shear flows, and to compare these predictions with our experimental measurements. Specifically, we aim to vary the molecular structure in the laboratory, and to explore its effect on the rheological response. Special problems arise when extending the kinetic molecular theory for polydisperse systems, since the relaxation spectrum departs from the Maxwell model. Over the next five years, my group will tackle these special theoretical problems. My new Queen's laboratory will soon be equipped with the latest breakthrough instrument for measuring rheological response in LAOS: cone-plate flow with plate partitioning. Having spent last summer collaborating in Germany to perfect this technique, I design this proposal to exploit the resources of my new Canada Research Chair in Rheology, and especially the new equipment on order from the corresponding CFI monies. We seek Discovery Grant support for postdoctoral and doctoral students to evaluate the latest advances in structural theory with careful measurements on polymeric liquids of known molecular structure.