Molecular Visualization: Spreading Kinematics and Dynamics

分子可视化：传播运动学和动力学

• 批准号: 0306787
• 负责人: Sergei Sheiko
• 金额: $ 29.2万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2006-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0306787&HistoricalAwards=false
• 关键词: Molecular; Visualization; Spreading; Kinematics; Dynamics

Spreading of thin polymer films on solid surfaces is of both fundamental and technological interest. During the last 20 years, significant experimental and theoretical studies have been carried out to understand the way fluids spread on surfaces. These have led to a macroscopic understanding of wetting; however, the molecular mechanism remains largely unknown. Thus, there is an apparent need for the development of experimental methods that are capable of visualization of individual molecules during spreading. It is proposed to develop an integrated system for monitoring molecular spreading based on a combination of AFM and fluorescent microscopy. It is also proposed to use branched polymer molecules as model systems that can be visualized by the chosen techniques. Four fundamental questions will be addressed in the project. (i) What is the conformation and packing of polymer chains confined to the surface plane? (ii) What is the spreading kinematics of polymer molecules in two dimensions and its correlation with the motion of the leading edge of the precursor film? (iii) What are the driving forces and dissipation channels, and their relative contribution to the wetting kinetics? (iv) What is the molecular pattern of the surface flow and its correlation with the surface structure of the substrate? This work will advance the fundamental understanding of the molecular mechanism of wetting and will also provide practical guidelines for manipulation of the molecular architecture to control the wetting kinetics.The project will also provide interdisciplinary research training for graduate and undergraduate students, since it combines fine polymer chemistry and advanced experimental techniques. An exceptional area of broader impact stems from the already established interactions with local high schools in form of regular scientific seminars and summer research at the UNC-Chapel Hill. In addition to the educational aspects, the project will reinforce collaborations in the Research Triangle Area including UNC, NCSU, and Duke University. Because of its innovative approach - investigation of material properties via visualization of individual molecules - this project will have broad impact on materials science and engineering in the area.

在固体表面上铺展聚合物薄膜具有基础和技术意义。在过去的 20 年里，人们进行了大量的实验和理论研究来了解流体在表面上的扩散方式。这些导致了对润湿的宏观理解；然而，其分子机制仍然很大程度上未知。因此，显然需要开发能够在扩散过程中可视化单个分子的实验方法。建议开发一种基于 AFM 和荧光显微镜相结合的监测分子扩散的集成系统。还建议使用支化聚合物分子作为可以通过所选技术可视化的模型系统。该项目将解决四个基本问题。 (i) 限制在表面平面的聚合物链的构象和堆积是什么？ (ii) 聚合物分子在二维中的扩散运动学及其与前体薄膜前缘运动的相关性是什么？ (iii) 驱动力和耗散通道是什么，以及它们对润湿动力学的相对贡献？ (iv) 表面流的分子模式及其与基材表面结构的相关性是什么？这项工作将增进对润湿分子机制的基本理解，并将为操纵分子结构以控制润湿动力学提供实用指南。该项目还将为研究生和本科生提供跨学科研究培训，因为它结合了精细聚合物化学和先进的实验技术。一个具有更广泛影响的特殊领域源于与当地高中已经建立的互动，以定期科学研讨会和北卡罗来纳大学教堂山分校夏季研究的形式进行。除了教育方面外，该项目还将加强北卡罗来纳大学、北卡罗来纳州立大学和杜克大学等研究三角地区的合作。由于其创新方法——通过单个分子的可视化来研究材料特性——该项目将对该领域的材料科学和工程产生广泛的影响。