Bond Tension, Surface Structure and Adsorption on Bottle-Brush Tethered Polymer Layers

该奖项支持理论和计算研究和教育，旨在对涂有瓶刷聚合物的表面进行基本理解，以增加表面的新功能，例如覆盖骨骼的软骨表面的瓶刷聚合物增加润滑。瓶刷聚合物在涂料和表面处理中有重要的应用，特别是对于耐特定蛋白质或对特定蛋白质有选择性的涂料，例如生物医学应用中需要对某些蛋白质有选择性的应用，以及通过去除这些杂质来过滤或修复水。聚合物是由分子串在一起形成长链分子。瓶刷分子的特征是侧链接枝到线性主链上，其密度如此之大，以至于侧链之间存在高度的斥力。这种排斥力导致沿侧链的张力传递到主链，主链可以用来破坏分子内的键以产生自我修改行为。对这些结构的性质进行实验评估在成本和时间上都是令人望而却步的，而且使这些分子有趣的相互作用通常发生在分子水平上，几乎不在实验研究的范围内。计算机模拟可以对不同长度和时间尺度的瓶刷分子进行研究，以评估特定应用中给定类别聚合物的性能。PI将使用计算机模拟来推进对瓶刷系住层的性质及其与瓶刷聚合物结构的关系的理解。这项工作将从根本上推进瓶刷聚合物的物理性质理论，特别是瓶刷聚合物附着在表面以增加新的功能。它还将为未来理论的发展提供一个框架，这些理论涉及新型聚合物结构的物理性质以及结构对聚合物基涂层表面性质的影响，基于替代聚合物结构的表面和表面处理。它将有助于基于替代聚合物结构的新型聚合物基材料、系统和设备的设计。因此，这项研究有助于实现材料基因组计划的目标。从研究中获得的知识有助于发现和理解由于新结构而产生的紧急效应，例如瓶刷聚合物中的张力积累和吸附阻力。除了使用该奖项对本科生和研究生进行培训和指导外，获得的新知识将被纳入研究生水平的课程。该奖项支持理论和计算研究，旨在推进对聚合物功能化表面（如聚合物瓶刷）的基本理解。通过在瓶刷系绳层中使用分子间或分子内张力进行自修饰的概念是一个相对较新的概念，直到最近几年才进行了实验研究。它最常用于分离链不与骨架保持在一起的情况，例如用于药物输送应用的涂层。然而，据我们所知，在致密的表面层中，表面层内侧链或瓶刷碎片的分离和扩散尚未通过模拟或实验进行广泛研究。根据电刷层的密度，以及电刷组分之间存在的任何分子间相互作用，侧链的脱离可能导致局部效应，例如重新定向到小范围区域，也可能具有全局效应，例如直接影响吸附特性和表面结构的电刷层的塑化。计算机模拟可以研究瓶刷聚合物和相关系统，从原子到粗粒度或连续体的尺度，以评估特定应用中给定类别聚合物的性能。PI将使用粗粒度分子动力学模拟来表征瓶刷系结层，以研究侧链接枝密度、相对主链/侧链长度以及刷组件的化学性质（例如共聚和非共价相互作用）变化的影响。PI将使用模拟来表征完整刷层和允许组件分离（侧链，刷段）的刷层的表面吸附特性，以研究分离动力学以及分离组件对刷层结构和表面特性的影响。这项工作将从根本上推进瓶刷聚合物的物理性质理论，特别是瓶刷聚合物附着在表面以增加新的功能。它还将为未来理论的发展提供一个框架，这些理论涉及新型聚合物结构的物理性质以及结构对聚合物基涂层表面性质的影响，基于替代聚合物结构的表面和表面处理。它将有助于基于替代聚合物结构的新型聚合物基材料、系统和设备的设计。因此，这项研究有助于实现材料基因组计划的目标。从研究中获得的知识有助于发现和理解由于新结构而产生的紧急效应，例如瓶刷聚合物中的张力积累和吸附阻力。除了使用该奖项对本科生和研究生进行培训和指导外，获得的新知识将被纳入研究生水平的课程。

NONTECHNICAL SUMMARYThis award supports theoretical and computational research and education aimed at a fundamental understanding of surfaces coated with bottle-brush polymers to add new function to the surface, for example bottle-brush polymers on the cartilage surface covering bone adds lubrication. Bottle-brush polymers have found important applications in coatings and surface treatments, especially for coatings that are resistant to particular proteins or selective to specific proteins, such as for applications requiring selectivity toward certain proteins in biomedical applications and for the filtering or remediation of water by removing such impurities. Polymers are made of molecules that are strung together to form long chain molecules. Bottle-brush molecules feature side chains grafted to a linear backbone at such density that there is a high degree of repulsion between side chains. This repulsion results in tension along the side chain which is transmitted to the backbone which may be harnessed to break bonds within the molecule to create self-modifying behavior. Experimental evaluation of the properties of such structures can be prohibitive in cost and time and the interactions that make such molecules interesting often occur at the molecular level, barely in range of experimental investigation. Computer simulation enables investigations of bottle-brush molecules at different length and time scales to evaluate the properties of given classes of polymers for a specified application. The PI will use computer simulation to advance understanding of the properties of bottle-brush tethered layers and their relationship to the architecture of bottle-brush polymers.This work will fundamentally advance the theory of physical properties of bottle-brush polymers and specifically bottle-brush polymers tethered to surfaces to add new functionality. It will also provide a framework for the development of future theory regarding the physical properties of novel polymer architectures and the effects of architecture in the surface properties of polymer-based coatings, surfaces and surface treatments based on alternative polymer structures. It will aid in the design of new polymer-based materials, systems, and devices based on alternative polymer architectures. As such, this research contributes to the goals of the Materials Genome Initiative. The knowledge gained from the research contributes to the discovery and understanding of emergent effects that result as a consequence of novel architectures, such as tension accumulation and adsorption resistance in bottle-brush polymers. In addition to training and mentoring of undergraduate and graduate students using this award, the new knowledge acquired will be incorporated in graduate level courses.NONTECHNICAL SUMMARYThis award supports theoretical and computational research aimed to advance fundamental understanding of polymer-functionalized surfaces such as polymer bottle-brushes. The concept of self-modification through the use of intermolecular or intramolecular tension within bottle-brush tethered layers is a relatively new one, having been investigated experimentally only in recent years. It has been most often applied to cases in which the detached chains do not remain with the backbone, such as in coatings for drug-delivery applications. In a dense surface layer, however, the detachment and diffusion of side chains or of bottle-brush fragments within the surface layer has not, to our knowledge, been extensively studied either by simulation or experiment. Depending on the density of the brush layer, as well as any present intermolecular interactions between brush components, detachment of side chains may lead to local effects, such as reorientation into small-scale domains or may have global effects, such as plasticization of the brush layer that directly affects the adsorption characteristics and surface structure. Computer simulation enables the investigation of bottle-brush polymers and related systems, at scales ranging from the atomic to the coarse-grained or continuum, to evaluate the properties of given classes of polymers for a specified application. The PI will use coarse-grained molecular dynamics simulation to characterize bottle-brush tethered layers to study the effects of variation in side-chain grafting density, relative backbone/side-chain length, and chemical nature of brush components, for example copolymerization and noncovalent interaction. The PI will use simulation to characterize the surface adsorption characteristics for intact brush layers and layers which allow component detachment (side chains, brush segments), to investigate detachment dynamics and the effect of detached components on the structure and surface characteristics of the brush layer.This work will fundamentally advance the theory of physical properties of bottle-brush polymers and specifically bottle-brush polymers tethered to surfaces to add new functionality. It will also provide a framework for the development of future theory regarding the physical properties of novel polymer architectures and the effects of architecture in the surface properties of polymer-based coatings, surfaces and surface treatments based on alternative polymer structures. It will aid in the design of new polymer-based materials, systems, and devices based on alternative polymer architectures. As such, this research contributes to the goals of the Materials Genome Initiative. The knowledge gained from the research contributes to the discovery and understanding of emergent effects that result as a consequence of novel architectures, such as tension accumulation and adsorption resistance in bottle-brush polymers. In addition to training and mentoring of undergraduate and graduate students using this award, the new knowledge acquired will be incorporated in graduate level courses.