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

1512221-Kilbey，S.Michael聚合物在日常生活中广泛存在，其界面的结构和性质决定了它们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，采用各种相同能量的构型。然而，当聚合物链由产生链刚性的重复单元组成时，在配置和抗弯方面的限制导致了截然不同的结构和行为。这项拟议的研究项目旨在调查链刚性的这些根本差异如何影响界面结构和性能。为了完成这项研究，将合成一种新型的聚合物，这种聚合物能够通过合成化学来调节链的微结构，从而调节链的刚性，并将拴在界面上，使用能够在纳米尺度上探测结构的各种技术来测量得到的结构和性能。这项研究的结果将促使人们对如何合理设计聚合物改性界面进行新的思考，这些界面适用于从结构纳米复合材料到先进能源系统的各种应用。计划开展一项涵盖聚合物合成、界面改性以及表面结构和性能表征的综合研究计划。基于聚苯并富烯(PBF)的新型末端功能聚合物(PBF)可以通过合成化学来调节链的微观结构，从而设定链的刚性和迁移率，将被合成和表征。通过活化表面的反应性改性，制备PBF的界面层，并研究PBF在平面上的结构、对不同性质的溶剂的结构响应以及表面能随分子量、微观结构和链面密度的变化。我们将研究涂有PBF链薄膜的PBF刷子的润湿行为，以揭示填充、排列和微观结构如何决定界面上的热力学相互作用。由一系列系统研究产生的结构-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在很大程度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，这种复合材料扩展了材料-性能空间的边界。半柔性聚合物是一类重要但研究不足的材料，与生物聚合物、用于能量转换的共轭聚合物以及机械坚固的合成纤维相关。清楚地了解链刚性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性提供的韧性和改善分散性的新型纳米复合材料至关重要。除了培训研究生和本科生外，参与该项目的研究人员还将参与针对中学生的外展和教育活动。这些活动的目标是通过指导和实践实验，促进年轻学习者的个人和职业成长，激发对工程和科学职业的好奇心和兴趣，并促进多样性。将通过邀请一名高中教师参与真实的研究体验来加强这一点，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。

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.