The Rheology Of Polymer Solutions In Ultrathin Films Via A Combined Finite Elements-Brownian Dynamics Approach

通过组合有限元布朗动力学方法研究超薄膜中聚合物溶液的流变学

• 批准号: 9732535
• 负责人: Bamin Khomami
• 金额: $ 15万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9732535&HistoricalAwards=false
• 关键词: Rheology; Polymer; Solutions; Ultrathin; Films

ABSTRACT Proposal Number: CTS-9732435 Principal Investigator: Khomani This is a grant to address a number of important problems in the study of polymer rheology that can be characterized as non-continuum or non-local. These are typically associated with the influence of boundaries or constrained environments on the stress-strain rate relationship. The burgeoning interest in these problems arises from the growing need to process materials at the molecular level. In most cases, new physical principles need to be applied to such problems because the most fundamental relationships, e.g. the relationship between the tension along a molecular backbone and the average extra stress in the mixture, need to be derived anew. Moreover these highly constrained flow fields are now only beginning to be experimentally interrogated, but the early data suggests that qualitatively new Theological behavior needs to be understood in these cases. Three problems that can serve as paradigms for theoretical model-building have been selected for study: a) the Couette-Poiseuille flow of flexible chains in solution when the pore or channel thickness is comparable to the radius of gyration of the polymers, b) the bulk shearing flow of polymer solutions near a boundary where the interface may contain adsorbed or grafted polymer layers, and c) the squeeze flow lubrication of "wet" polymer brush covered surfaces. The technique will be used is a novel hybrid scheme involving self-consistent flow calculations using HP adaptive finite elements and large scale Brownian dynamics simulations of bead-rod (Kramer's) chains.

摘要建议编号：CTS-9732435主要研究者：Khomani这是一种拨款，旨在解决聚合物流变性研究中许多重要问题的赠款，这些问题可以被视为非智能或非本地。 这些通常与边界或约束环境对应力 - 应变率关系的影响有关。 对这些问题的新兴兴趣源于在分子水平上处理材料的日益增长的需求。 在大多数情况下，需要将新的物理原则应用于此类问题，因为最基本的关系，例如沿分子主链的张力与混合物中平均额外应力之间的关系需要重新得出。 此外，这些高度约束的流场现在才刚刚开始对实验进行询问，但是早期的数据表明，在这些情况下，定性上需要了解新的神学行为。已经选择了可以作为理论模型建设范式的三个问题进行研究：a）当孔或通道厚度与聚合物的循环半径相当时，溶液中柔性链中的脉冲脉流动流动，b）界面的散布在界面附近的聚合物剪切范围可能包含ad的界面，这些界面可能会散发出且均匀的缝隙，并散发出杂交的缝隙），该界面及其被涂料的缝隙均匀划分了。 “湿”聚合物刷覆盖表面。 该技术将用于一种新型的混合方案，涉及使用HP自适应有限元和大规模的Brownian Dynamics模拟珠棒（Kramer's）链的大规模布朗动力学模拟。