Cooperation with Germany: Studies of Polyelectrolyte Brushes in Confined Environments

在这个由化学系的大分子、超分子和纳米化学项目资助的项目中，康奈尔大学的克里斯托弗·奥伯将研究刷子的物理化学。这项工作包括与德国弗赖堡大学的Jurgen Ruhe教授的国际合作。 Ruhe教授的工作将由德国研究共同体（DFG）资助。 聚电解质刷是特别令人感兴趣的，因为它们的特征在于限制，这迫使聚合物链进入很大程度上拉伸的构象，以及沿着聚合物主链沿着存在电荷。该国际团队将研究微刷的膨胀如何与使用先进光刻法产生的纳米结构的尺寸成比例，以及该系统如何从二维图案的膨胀过渡到三维结构的膨胀。此外，该团队将表征刷子高度，电荷和密度对与可溶性物质相互作用的影响，并确定稳定刷子结构和防止“熵死”的有希望的策略，即刷子表面的熵诱导链断裂。更广泛的影响涉及积极的国际交流，使研究生和相关的本科生研究人员接触到全球研究伙伴关系。此外，还将举办针对特定主题的暑期学校，以更深入地思考聚合物刷研究中遇到的问题类型。聚合物是长链有机分子，在日常生活中使用塑料的许多方面都存在，包括食品包装，汽车和航空航天运输的结构材料以及轻质电子设备。 大自然在界面处使用带电聚合物膜来控制润滑，限制生物污垢，并帮助保持表面湿润。 该研究旨在开发和理解稳定，可持续的表面结构，这些结构与可溶性，合成或生物材料进行受控的相互作用。 通过开发新的化学成分和工艺策略，这项研究可以为生物医学设备，环境和医疗传感器以及环境友好涂层提供更好的材料。

In this project funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Christopher Ober of Cornell University will study the physical chemistry of polyelectrolyte brushes. This work includes an international collaboration with Prof. Jurgen Ruhe of the University of Freiburg, Germany. Prof. Ruhe's work will be funded by the Deutsche Forschungsgemeinschaft (DFG). Polyelectrolyte brushes are of particular interest because they feature both confinement, which forces the polymer chains into a largely stretched conformation, and the presence of charges along the polymer backbones. The international team will investigate how the swelling of polyelectrolyte brushes scales with the size of a nanostructure produced using advanced lithography and how the system transitions from swelling of a two-dimensional pattern into swelling of a three-dimensional structure. Furthermore, the team will characterize the effects of brush height, charge and density on interactions with soluble species and establish what are promising strategies to stabilize polyelectrolyte brush structures and prevent "entropic death," that is the entropy induced breakage of chains from the brush surface. The broader impacts involve active international exchanges exposing graduate students and associated undergraduate researchers to a global research partnership. Additionally, summer schools will be hosted on specific topics that enable a deeper consideration of the types of problems encountered in the study of polymer brushes.Polymers are long chain organic molecules and are found in many facets of everyday life that utilize plastics, including food packaging, structural materials for automotive and aerospace transportation, and lightweight electronic devices. Nature uses charged polymer films at interfaces to control lubrication, to limit biofouling, and to aid in keeping surfaces wet. This research seeks to develop and understand stable, sustainable surface structures that undergo controlled interactions with soluble, synthetic or biological materials. Through development of new chemical components and process strategies, this research could lead to better materials for biomedical devices, environmental and medical sensors, and environmentally friendly coatings.