Multi-Scale Analysis and Simulation of Nanofiber Coatings: Growth and Applications

建议：DMS-0305580PI：Gerald W.Young[gwYoung@uakron.edu]机构：阿克伦大学标题：纳米纤维涂层的多尺度分析和模拟：生长和应用该项目建议开发用于模拟纳米纤维涂层生长的多尺度数学模型和算法。在过滤、复合材料、生物医学和电子领域中，包覆的纳米纤维以及在纳米纤维核心溶解后产生的纳米管具有潜在的应用。对这些高质量纳米材料应用的不断增长的需求推动了对描述涂层过程的模型以及描述所制造的纳米纤维和纳米管的材料和电磁特性的模型的需求。通过物理气相沉积(PVD)方法对纳米纤维进行涂层是一个还不完全了解的过程。虽然关于纳米沉积技术的数据已经收集了十多年，但还没有开发出涂层过程的全面量化模型。拟议的研究通过概述一项计划来满足这一及时需求，该计划旨在开发在连续介质长度尺度上的涂层生长的真正多尺度模型和模拟，同时携手进行实验验证。PVD方法允许控制实验条件，因此实验结果与模型预测之间的比较将是直截了当的。将渐近分析、数值模拟、量子力学和分子动力学联系起来的计划构成了研究纳米现象的重要一步。这些模型和模拟将把PVD等离子体反应器中的全局连续介质模型、涂覆纤维周围的局部纳米模型以及原子尺度的量子力学和分子动力学模型联系起来。这些模型将向涂层生长的宏观尺度模型提供输入，从而可以通过水平集方法跟踪涂层的形态。多尺度建模、模拟和实验工作的总体目标是了解PVD工艺参数如何影响涂层生长，确定控制涂层生长的最佳参数范围，解释尚未很好理解的涂层生长的实验观察，并确定最终产品的有效电磁性能。该项目建议开发多尺度数学模型和算法来模拟纳米纤维上涂层的生长。用特定材料对纳米纤维进行涂层是一种相对较新的工艺，用于生产涂层纳米纤维和纳米管(去除纳米纤维芯后产生的)。这些纳米结构在过滤、复合材料、生物医学和电子领域有许多潜在的应用。所提出的建模和实验工作的结合将有助于解决有关纳米纤维涂层的物理和化学以及涂层性能的基本未解答问题。特别是，该项目将提供必要的了解，以控制涂层厚度和均匀性，以生产具有所需尺寸特征的纳米管。除了对科学研究的影响外，该项目还将加强对研究生纳米级建模的培训。这对于发展强大的纳米技术工业基础至关重要。这一研究项目将允许阿克伦大学开发必要的专业知识，以增强现有的课程，包括研究生和本科生的纳米技术建模专业。此外，预计在这项研究工作中获得的对纳米级制造过程的更好理解将使制造商能够改进现有产品和开发新产品。

Proposal: DMS-0305580PI: Gerald W. Young [gwyoung@uakron.edu]Institution: University of AkronTitle: MULTISCALE ANALYSIS AND SIMULATION OF NANOFIBER COATINGS: GROWTH AND APPLICATIONSABSTRACTThis project proposes to develop multiscale mathematical models and algorithms for simulating the growth of a coating on a nanofiber. There is potential application for coated nanofibers, and the nanotubes that result after dissolution of the nanofiber cores, in the areas of filtration, composites, biomedicine, and electronics. The ever increasing demand for these high quality nanomaterials applications drives the need for models that describe the coating process as well as models that describe the material and electromagnetic properties of manufactured nanofibers and nanotubes. The coating of nanofibers by physical vapor deposition (PVD) methods is a process that is only partially understood. While data on nanodeposition techniques have been collected for over a decade, a comprehensive quantitative model of the coating process has not yet been developed. The proposed research addresses this timely need by outlining a plan to develop truly multiscale models and simulations of coating growth at the continuum length scale while proceeding hand-in-hand with experimental validation. The PVD method allows for control over the experimental conditions so that comparisons between the experimental results and themodel predictions will be straightforward. The plan to link asymptotic analysis, numerical simulation, quantum mechanics and molecular dynamics constitutes a major step in the study of nanoscale phenomena. The models and simulations will connect global continuum models in a PVD plasma reactor, local nanoscale models around a coated fiber, and quantummechanical and molecular dynamics models at the atomistic scale. These models will provide inputs to a macroscopic scale model of the coating growth so that the morphology of the coating can be tracked via a level set method. The overall goals of the multiscale modeling, simulation, and experimental efforts are to provide an understanding of how PVD process parameters affect the coating growth, to identify an optimal range of parameters for controlling the growth, to explain experimental observations of coating growth that are not well understood, and to determine the effective electromagnetic properties of the completed product.This project proposes to develop multiscale mathematical models and algorithms for simulating the growth of a coating on a nanofiber. The coating of nanofibers with specific materials is a relatively new process for producing coated nanofibers and nanotubes (that result after removing the nanofiber cores). These nanostructures have many potential applications in filtration, composites, biomedicine, and electronics. The proposed combination of modeling and experimental efforts will help to address the fundamental unanswered questions concerning the physics and chemistry of nanofiber coating and the properties of the coating. In particular, this project will provide the understanding necessary to control the coating thickness and uniformity to produce nanotubes with desired dimensional features. In addition to its impact on scientific research, this project will enhance the training of graduate students in nanoscale modeling. This is essential for the development of a strong industrial base in nanotechnology. This research project will allow The University of Akron to develop the expertise necessary to augment existing programs to include a specialization in nanotechnology modeling, at the graduate and the undergraduate level. Further, it is anticipated that the enhanced understanding of nanoscale manufacturing processes gained during this research effort will allow manufacturers to improve existing products and to develop new products.