Multiscale modelling of nanostructured soft materials

我的研究重点是增加我们对液晶，纳米颗粒和聚合物混合物的理解，并帮助开发这些复杂系统的新应用。 本论文的主要目的是：（1）研究强约束和表面润湿对聚合物非平衡动力学的影响，（2）深入了解液晶有序性、界面形状和胶体粒子在液晶中的自组织性之间的相互作用;以及（3）了解混合到聚合物熔体中的纳米纤维的有序化如何在纤维周围的聚合物基质中诱导局部有序化。 在这些系统中，微观尺度上相互作用的微妙平衡导致了一系列脆弱的紧急状态。 因此，通过研究这些杂化材料，我们希望能够更全面地了解无序、挫折和失衡行为的后果。为了达到这些目标，我们将模拟这些系统使用多尺度计算模型，其功能形式和本构系数将主要基于实验可实现的系统。 将物体浸入液晶或聚合物熔体中会在基质的取向有序（或无序）与胶体包裹体表面的优选有序之间产生竞争。 我们将使用模拟来表征浸没物体的行为，无论是溶液中的受限聚合物，还是液晶或聚合物熔体中的夹杂物。 这些模拟将帮助我们识别所观察到的物理现象的起源，并指导利用这些效应的材料和设备的设计。 我的研究的长期目标是双重的。首先，我们希望利用我们的研究结果来设计和操纵纳米颗粒，液晶和聚合物之间的相互作用，以创造具有理想性能的新型纳米结构材料。其次，我们希望获得设计更有效的微流变学分析工具和纳米流体设备中单分子（如DNA）操作的知识。

The focus of my research is to increase our understanding of hybrid mixtures of liquid crystals, nanoparticles, and polymers and to aid the development of novel applications for these complex systems.  The objectives are the following: (1) to study the effect of strong confinement and surface wetting on the non-equilibrium dynamics of polymers; (2) to gain insight into the interplay between liquid crystalline order, interface shape, and the self-organization of colloidal particles immersed in a liquid crystal; and (3) to learn how the ordering of nanofibers mixed into a polymer melt induces local order in the polymer matrix surrounding the fibers.   The delicate balance of interactions at the microscale in these systems leads to a fragile set of emergent states.  As a result, by studying these hybrid materials we hope to achieve a more complete understanding of the consequences of disorder, frustration, and out-of-equilibrium behavior. To reach these goals, we will simulate these systems using multi-scale computational models whose functional form and constitutive coefficients will be based primarily on experimentally realizable systems.  Immersing objects in a liquid crystal or polymer melt creates competition between the orientational order (or disorder) of the matrix and the preferred ordering at the surface of the colloidal inclusion.  We will use simulations to characterize the behaviour of immersed objects, whether confined polymers in solution, or inclusions in a liquid crystal or polymer melt.  These simulations will help us to identify both the origin of the observed physical phenomena and guide the design of materials and devices that exploit these effects. The long-term goals of my research are two-fold. First, we wish to use our findings to design and manipulate interactions between nano-particles, liquid crystals, and polymers to create novel nanostructured materials with desirable properties. Second, we hope to acquire knowledge for designing more effective analysis tools for microrheology and the manipulation of single molecules (like DNA) in nanofluidic devices.