UNS: Organization and Interfacial Interactions of Surface-tethered Layers of Semiflexible Polymer Chains

UNS：半柔性聚合物链表面束缚层的组织和界面相互作用

• 批准号: 1512221
• 负责人: S Michael Kilbey
• 金额: $ 28.15万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-15 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1512221&HistoricalAwards=false
• 关键词: UNS; Organization; Interfacial; Interactions; Surface

1512221 - Kilbey, S. MichaelPolymers are widely encountered in daily life, and the structure and properties of their interfaces dictate their use and functioning in many applications. In most situations, the constituent polymers are considered to be coiled, flexible chains that adopt a variety of configurations of equal energy. However, when polymer chains are made of repeat units that give rise to chain stiffness, restrictions in configuration and resistance to bending lead to drastically different structures and behaviors. The proposed research project aims to investigate how those fundamental differences in chain stiffness impact interfacial structure and properties. To accomplish this research, a new type of polymer that enables chain microstructure, and therefore chain stiffness, to be tuned through synthetic chemistry will be synthesized, tethered to interfaces, and the resultant structure and properties will be measured using a variety of techniques capable of probing structure at the nanoscale. Results from this research will catalyze new thinking into how to rationally design polymer-modified interfaces that are useful in applications ranging from structural nanocomposite materials to advanced energy systems.A comprehensive research program encompassing polymer synthesis, interface modification and surface structure and property characterization is planned. Novel end-functional polymers based on poly (benzofulvene) (PBF), which enables chain microstructure to be tuned through synthetic chemistry, thereby setting chain stiffness and mobility, will be synthesized and characterized. Interfacial layers of PBFs will be made by reactive modification of activated surfaces, and the organization, structural response to solvents of different quality, and surface energy of those PBF "brushes" on flat surfaces will be investigated as a function of molecular weight, microstructure, and areal density of chains. The wetting behavior of PBF brushes coated with thin films of PBF chains will be examined to reveal how packing, arrangement, and microstructure dictate thermodynamic interactions across interfaces. The structure-property relationships resulting from sets of systematic studies will provide new foundational knowledge of the interfacial behaviors of semi flexible polymers, which is transformative not only because it addresses a research area that is largely vacant of experimental insights, but also because it establishes a basis for developing advanced nanocomposites that expand the boundaries of materials-property space.Semiflexible polymers are an important but under-studied class of materials that are relevant to biological polymers, conjugated polymers used in energy conversion, and mechanically robust synthetic filaments. A clear understanding of how chain stiffness and orientation interactions affect thermodynamic behaviors and interfacial structure is essential to support continue technological advances in those areas, as well as to develop new nanocomposites that make use of toughness and improved dispersion provided by chain rigidity. In addition to training graduate and undergraduate students, researchers engaged in this program will participate in outreach and education initiatives aimed at middle school students. These activities have goals of fostering personal and professional growth in young learners through mentoring and hands-on experimentation, inspiring curiosity and interest in careers in engineering and science, and promoting diversity. These will be augmented by engagement of a high school teacher in an authentic research experience, and results from all activities will be shared through publications and presentations at local and national conferences.

1512221 - Kilbey，S.迈克尔聚合物在日常生活中广泛使用，其界面的结构和性能决定了其在许多应用中的用途和功能。在大多数情况下，组成聚合物被认为是卷曲的，柔性的链，采用各种构型的相等的能量。然而，当聚合物链由产生链刚度的重复单元组成时，构型和抗弯曲性的限制会导致截然不同的结构和行为。拟议的研究项目旨在研究链刚度的根本差异如何影响界面结构和性能。为了完成这项研究，一种新型的聚合物，使链的微观结构，因此链的刚度，通过合成化学调整将被合成，拴系到界面，并得到的结构和性能将被测量使用各种技术能够探测结构在纳米级。该研究成果将为如何合理设计聚合物改性界面提供新的思路，这些界面在从结构纳米复合材料到先进能源系统的应用中非常有用。基于聚（苯并富烯）（PBF）的新型末端官能聚合物，其能够通过合成化学调节链的微观结构，从而设置链刚度和流动性，将被合成和表征。PBFs的界面层将通过活性表面的反应性改性制成，并且将研究作为分子量、微观结构和链的面密度的函数的组织、对不同质量的溶剂的结构响应以及那些PBF“刷”在平坦表面上的表面能。PBF刷涂薄膜的PBF链的润湿行为将被检查，以揭示如何包装，安排，和微观结构决定跨界面的热力学相互作用。从一系列系统研究中得出的结构-性能关系将为半柔性聚合物的界面行为提供新的基础知识，这不仅是因为它解决了一个基本上缺乏实验见解的研究领域，而且还因为它为开发先进的纳米复合材料奠定了基础，这些纳米复合材料扩展了材料性能空间的边界。半柔性聚合物是一种重要但不足的材料，研究了与生物聚合物、用于能量转换的共轭聚合物和机械坚固的合成长丝相关的一类材料。清楚地了解链刚度和取向相互作用如何影响热力学行为和界面结构对于支持这些领域的持续技术进步以及开发利用链刚度提供的韧性和改善的分散性的新纳米复合材料是必不可少的。除了培训研究生和本科生外，参与该计划的研究人员还将参与针对中学生的宣传和教育活动。这些活动的目标是通过指导和实践实验，激发对工程和科学职业的好奇心和兴趣，促进年轻学习者的个人和专业成长，并促进多样性。这些将通过一名高中教师参与真实的研究经验来增强，所有活动的结果将通过出版物和在地方和国家会议上的演讲来分享。