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

拟议的研究是基于跨学科的努力，涉及聚合物表面化学，界面操作和先进的纳米/微加工技术。通过在微观和纳米尺度上在地形结构表面的特定位置的表面粗糙度的相互作用，对表面性质的定量理解将会发展并测试不完全理解的基本理论。具体来说，PI计划：1)设计新的化学路线，选择性地将聚合物刷枝接枝到纳米图案表面的尖端；2)开发新的合成和制造策略，以在空间上控制硅和聚合物纳米结构上聚合物刷的接枝密度、（相对）链长、组成、结构和位置；3)合成各种越来越复杂的响应刷，系统地研究它们在图案衬底上的折叠和扩展状态下的结构和功能；4)定量地将分子参数与响应小温度变化的表面润湿性和转变的驱动力联系起来。大自然提供了具有多面功能的分层架构的极好例子。例如，动物的皮毛将纤维的尖端拉在一起，同时使它们离皮肤更近，从而使水从皮毛上脱落。壁虎的脚是自洁的，脚尖上有干胶。受独特的自然设计的启发，该方案旨在开发新颖的合成方法，在空间上控制和切换三维的表面/界面特性。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，而且还将影响各种技术，包括微流体、受控装配和材料合成、细胞工程和软机器人。通过新的培训和拓展机会，各级学生将接触到化学、材料科学和工程以及纳米技术等各种主题，包括年度研究静修、新课程开发和贝尔实验室、朗讯技术的工业实习。

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.