Large-Amplitude Oscillatory Shear Flow of Polymeric Liquids

流变学是研究物质流动和变形的学科。不是简单的物质，比如水或空气，而是复杂的物质，比如粘稠的、有弹性的液体。这些液体很复杂，因为它们的分子很长，呈链状。我的流变学研究都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。我们将通过在最新的昂贵、复杂的计算机化仪器流变仪中仔细摇动聚合物分子来发现这些联系。在我的发现基金期间，以及之后的几年里，我的团队将探索弹性液体的分子结构与它们在被称为大振幅振荡剪切（LAOS）的振动实验中的流变学之间的关系。******我们关心振荡剪切，因为它是最流行的粘弹性特性测量，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多样的有趣细节。自从我就这个课题发表了博士论文[麦吉尔大学，化学工程（1987年）]以来，我的小组一直是老挝聚合物液体表征方面的领先实验室。***为了加深我们对这些响应的理解，在液体微观结构方面，我的团队现在将注意力转向利用分子动力学理论来探索老挝分子结构与应力响应之间的联系[JCP， 140, 074904(2014)]。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结果进行比较。具体来说，我们的目标是在实验室中改变分子结构，并探索其对流变反应的影响。在推广多分散体系的分子动力学理论时，由于弛豫谱偏离了麦克斯韦模型，出现了一些特殊问题。在接下来的五年里，我的小组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响应：带板分区的锥板流动。去年夏天，我在德国合作完善了这项技术，我设计了这个方案，以利用我在流变学方面的新加拿大研究主席的资源，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生寻求发现基金支持，通过对已知分子结构的聚合物液体的仔细测量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.**