CAREER: Selective Grafting of Responsive Polymer Brushes on Topographically Structured Surfaces: A New Route for Surface and Interface Manipulation

这项拟议的研究是基于一项跨学科的努力，涉及聚合物表面化学、界面操纵和先进的纳米/微制造技术。通过微观和纳米尺度表面粗糙度在特定位置的相互作用，对表面性质的定量理解将发展并检验尚未完全理解的基本理论。具体地说，PI计划：1)设计新的化学路线，仅在纳米涂层表面的尖端选择性地接枝聚合物刷子；2)开发新的合成和制备策略，以空间控制硅和聚合物纳米结构上聚合物刷子的接枝密度、(相对)链长、组成、结构和位置；3)合成各种日益复杂的响应性刷子，以系统地研究它们在图案化衬底上折叠和延伸状态下的结构和功能；4)定量地将分子参数与表面润湿性和响应微小温度变化的转变的驱动力联系起来。自然提供了具有多方面功能的层次化体系结构的优秀示例。例如，动物毛皮将纤维的尖端拉在一起，同时使它们更接近皮肤，从而允许水从毛皮上剥离。壁虎的脚是自我清洁的，脚趾尖上有干胶水。受独特的自然设计的启发，这项提议旨在开发新的合成方法，将在三维空间控制和切换表面/界面属性。它不仅将为如何操纵表面润湿性和粘附性提供重要的科学见解，而且还将影响包括微流体、受控组装和材料合成、细胞工程和软机器人在内的各种技术。所有级别的学生将通过新的培训和拓展机会接触到化学、材料科学和工程以及纳米技术方面的一系列不同主题，包括年度研究务虚会、新课程开发和在贝尔实验室、朗讯技术公司的工业实习。

The proposed research is based on an interdisciplinary effort that involves polymer surface chemistry, interface manipulation, and advanced nano-/microfabrication techniques. Through the interplay of surface roughness at the micro- and nano- scales at specific locations on a topographically structured surface, a quantitative understanding of surface properties will evolve and test the incompletely understood basic theories. Specifically, the PI plans to: 1) design new chemical routes to selectively graft polymer brushes only on the tip of the nanopatterned surface; 2) develop novel synthetic and fabrication strategies to spatially control the grafting density, (relative) chain length, composition, architecture, and location of polymer brushes on the silicon and polymer nanostructures, 3) synthesize a variety of responsive brushes with increasing complexity, to systematically investigate their structure and function in collapsed and extended states on a patterned substrate; 4) quantitatively relate molecular parameters to the driving forces for the surface wettability and transition in response to a small temperature change. Nature offers excellent examples of hierarchical architectures with multi-faceted functions. For example, animal fur pulls the tips of the fibers together while keeping them separated closer to the skin, allowing for the sheeting of water off the fur. The geckos foot is self-cleaning, dry adhesive on the tips of the foot toes. Inspired by the unique natural designs, this proposal aims to develop novel synthetic approaches that will spatially control and switch the surface/interfacial properties in three dimensions. It will not only provide important scientific insights of how to manipulate surface wettability and adhesion, but also will impact a diverse range of technologies, including microfluidics, controlled assembly and material synthesis, cell engineering, and soft robotics. Students at all levels will be exposed to a diverse range of topics in chemistry, materials science and engineering, and nanotechnology through new training and outreach opportunities, including an annual research retreat, a new course development, and industrial internships at Bell Laboratories, Lucent Technologies.