Polymer Dynamics at Surfaces and in Complex Media

技术总结：这项研究将对聚合物如何在表面和受限几何形状中扩散产生新的理解。 实验将基于使用荧光光谱的新实验平台，有时具有单分子分辨率（FCS，荧光相关光谱），有时具有FRAP（光漂白后的荧光恢复）。 实施，这两个实验将产生空间分辨率为0.5毫米的空间分辨测量。许多有趣的和相关的变量将被执行，与现有的理论相比，并用于鼓励新理论的发展。 提出了两项具体任务。 首先，我们将确定表面扩散如何依赖于链长和表面覆盖的聚合物吸附到固体表面从稀溶液。 其次，我们将研究聚合物熔体扩散在很宽的范围内的控制界面厚度，从纳米到微米。 这些实验将使一个新的仪器平台，将荧光实验整合到一个表面力装置。 新颖的光学设计和卓越的尺寸稳定性将使我们能够测量横向表面扩散如何取决于薄膜厚度。 在固体表面一侧，将探讨表面化学成分的关键作用。 在界面的聚合物侧，我们将关注关键控制方面，包括聚合物链长依赖性、聚合物表面覆盖率，以及在分子薄膜的情况下膜厚度，寻求理解这个问题的普遍方面 非技术性总结：本论文主要研究高分子材料物理性能的一个核心问题，即高分子如何沿固液界面沿着扩散，并在有限的几何空间内扩散。 科学发现将发展新的理解，这是许多科学和技术应用的基础，包括粘合，相互扩散，摩擦，以及复合材料和纳米复合材料的机械行为。 这项工作将进口，到高分子材料物理学领域，具有单分子灵敏度的荧光方法，为这一领域的特殊承诺。 这将通过开发该学科以前未使用的新技术来改善聚合物领域的研究基础设施。 研究生和本科生将与来自化学，化学工程，物理和材料科学的其他学生组成跨学科研究小组。

TECHNICAL SUMMARY: This research will develop new understanding of how polymers diffuse at surfaces and in confined geometries. The experiments will be based on using novel experimental platforms of fluorescence spectroscopy, sometimes with single-molecule resolution (FCS, fluorescence correlation spectroscopy), sometimes with FRAP (fluorescence recovery after photobleaching). As implemented, both experiments will yield spatially-resolved measurements with spatial resolution 0.5 mm. Many interesting and relevant variables will be performed, compared to available theory, and used to encourage the development of new theories. Two specific tasks are proposed. First, we will determine how surface diffusion depends on chain length and surface coverage for polymers adsorbed to solid surfaces from dilute solution. Second, we will study polymer melt diffusion over a wide range of controlled interfacial thickness, from nm to microns. These experiments will be enabled by a novel instrumental platform for integrating fluorescence experiments into a surface forces apparatus. Novel optical designs and exceptional dimensional stability will enable us to measure how lateral surface diffusion depends on thin film thickness. On the side of the solid surface, the critical role of the surface chemical composition will be explored. On the polymer side of the interface, we will focus on critical controlling aspects including the polymer chain length dependence, the polymer surface coverage, and in the case of molecularly-thin films, the film thickness, seeking to understand the universal aspects of this problem NON-TECHNICAL SUMMARY: This research focuses on a central problem of polymer materials physics performance how polymers diffuse along the solid-liquid interface and in confined geometries. The scientific findings will develop new understanding that is fundamental in many scientific and technical applications, including adhesion, interdiffusion, friction, and the mechanical behavior of composite and nanocomposite materials. This work will import, into the field of polymer materials physics, fluorescence methods with single-molecule sensitivity that hold exceptional promise for this field. This will improve research infrastructure in the polymer field by developing new techniques not previously used in this discipline. The graduate and undergraduate students will be part of an interdisciplinary research group with other students from chemistry, chemical engineering, physics, and materials science.