Design and Development of Super Water- and Oil-Repellent Surfaces by Topographic Manipulation

美国宾夕法尼亚州匹兹堡大学化学与石油工程系和机械工程系，宾夕法尼亚州匹兹堡大学化学与石油工程系和机械工程系15261超疏水和憎油表面，其水和油的接触角分别大于150，在绿色建筑、自清洁产品和微流体系统中有很大的应用价值。通常，材料平面上的接触角需要大于90，才能通过调整表面粗糙度来进一步增加接触角。然而，这项拟议的研究旨在通过在微米和纳米尺度上操纵表面形貌，从本质上亲水/亲油的材料(其平面上的接触角小于90)开发出超疏水/憎油表面。这将通过构建由悬挑组成的设计地形的表面来实现。突出部分将通过提供位置来支撑位于固体和空气复合表面之上的液体，从而诱导形成FAKIR液滴，这将导致宏观上的疏水/憎油。此外，将设计和制造分层的地形配置，以进一步增加所构建表面的疏水性/憎油性。还将研究液体在构造表面上的动态特性(如滑动、蠕动、滚动和反弹)。该项目将把研究和教育结合起来，增加代表性不足的群体的参与，并扩大到小学和让年轻学生接触表面科学。

Abstract Design and Development of Super Water- and Oil-Repellent Surfaces by Topographic ManipulationDi Gao and Hsin-Hua HuDepartment of Chemical and Petroleum Engineering and Department of Mechanical EngineeringUniversity of Pittsburgh, Pittsburgh, PA 15261Super-hydrophobic and oleophobic surfaces with contact angles of greater than 150 for water and oil, respectively, are of great interest for applications in green construction, self-cleaning products, and microfludic systems. Typically, a contact angle of greater than 90 on the flat surface of a material is required to further increase the contact angle by tuning the surface roughness. However, the proposed research aims to develop super-hydrophobic/oleophobic surfaces from intrinsically hydrophilic/oleophilic materials (with contact angles of less than 90 on their flat surfaces) by manipulating the surface topography in micro- and nano-scales. This will be realized by constructing surfaces with designed topographies consisting of overhangs. The overhangs will induce the formation of fakir liquid droplets by providing positions to support the liquid sitting above a composite surface of solid and air, which will result in a macroscopic hydrophobicity/oleophobicity. In addition, hierarchical topographic configurations will be designed and fabricated to further increase the hydrophobicity/oleophobicity of the constructed surfaces. Dynamic properties of liquids (such as sliding, creeping, rolling, and bouncing) on the constructed surfaces will also be investigated. This project will integrate research and education by increased participation of underrepresented groups, and outreach to elementary schools and exposure of young students to surface science.