Macromolecular Fluids: Theory, Simulation and Experiment

在粘性溶剂或柔性聚合物溶液中，新型材料被加工成“设计”大分子的液体混合物。这些大分子的范围从小分子量，棒状液晶到纳米粘土片，针对各种高性能材料和设备。分子被很好地近似为椭球体，通过新兴的理论、计算和实验可以精确地归入大分子流体的范畴。此外，悬浮在粘性溶剂中的刚性单元、单分散分子是基本的模型体系。在数学上，它们代表了理论的前沿；从物理上讲，它们是许多微流体系统现在可以理想地建模并最终理解的基础。导电性或阻隔性虽然决定材料的最终用途，但在加工过程中是被动的。更确切地说，设计和控制的基本问题是在加工过程中出现的远离单个分子的长度尺度（高达微米）结构，称为介观结构，它在经验上主导着最终的性能特征。例子包括隔离的液晶岛阵列，以及在棒状和圆盘状纳米复合材料中出现的不同模式。在刚性单位大分子流体的原型流动中，介观结构的开始、发展和饱和是工作的主要焦点。这项工作确定开放的数学，数值和实验问题，并构建集体策略，以解决这些问题，结合实验，理论和计算专业知识。在粘性溶剂或聚合物熔体和溶液中，新型材料被加工成“设计大分子”的液体混合物，其中设计大分子具有几到几百纳米的简单几何形状（1纳米等于1米的十亿分之一）。在材料加工过程中，微米级（1微米是1米的百万分之一）的介观结构的出现决定了材料的性能。PI与复杂流体领域的一组领先的实验学家合作，确定开放的数学，数值和实验问题，并结合实验，理论和计算专业知识构建解决这些问题的集体策略。

New classes of materials are processed as liquid mixtures of "designer" macromolecules either in viscous solvents or in flexible polymer solutions. These macromolecules range from small molecular weight, rod-like liquid crystals to nano-clay platelets, targeting a diverse family of high-performance materials and devices. The molecules are well approximated as ellipsoids, precisely falling within the class of macromolecular fluids accessible by emerging theory, computation, and experiment. Furthermore, rigid-unit, monodisperse molecules suspended in viscous solvent are fundamental model systems. Mathematically, they represent the leading edge of theory; physically, they are the foundation from which many micro-fluidic systems can now be ideally modeled, and eventually understood. Conductivity or barrier properties, while governing material end-use, are passive during processing. Rather, the fundamental issue for design and control is the emergence of structures during processing at length scales (up to microns) far removed from individual molecules, called mesostructures, which empirically dominate ultimate performance features. Examples include sequestered island arrays of liquid crystals and distinguished patterns that arise in rod-like and disc-like nano-composites. The onset, development, and saturation of mesostructures in prototypical flows of rigid-unit macromolecular fluids is the primary focus of the workl. The work identifies open mathematical, numerical, and experimental issues, and constructs collective strategies toward their resolution, combining experimental, theoretical and computational expertise. New class of materials are processed as liquid mixtures of "designer macromolecules"either in viscous solvents or in polymer melts and solutions, in which the designermacromolecules are of simple geometry in a few to several hundred nanometers (1 nanometer isequal to 1 billionth of 1 meter). The material properties are dominated by the emergence of the mesostructure at the micron level (1 micron is 1 millionth of 1 meter) during the material processing. The PI, teamed up with a group of leading experimentalists in the field of complexfluids, identifies the open mathematical, numerical and experimental issues and constructscollective strategies toward their resolution combining experimental, theoretical and computationalexpertise.