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

高迪和胡新华匹兹堡大学化学与石油工程系和机械工程系，匹兹堡，PA 15261分别对水和油具有大于150 °的接触角的超疏水和疏油表面在绿色建筑中的应用具有极大的兴趣，自清洁产品和微流体系统。通常，需要在材料的平坦表面上大于90 °的接触角，以通过调节表面粗糙度来进一步增加接触角。然而，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（在其平坦表面上接触角小于90）开发超疏水/疏油表面。这将通过构建具有由悬突组成的设计形貌的表面来实现。悬突将通过提供位置以支撑位于固体和空气的复合表面上方的液体来诱导fakir液滴的形成，这将导致宏观疏水性/疏油性。此外，将设计和制造分层拓扑结构，以进一步增加构建表面的疏水性/疏油性。还将研究构造表面上的液体的动态特性（如滑动、爬行、滚动和弹跳）。该项目将通过增加代表性不足的群体的参与，以及向小学推广和让年轻学生接触表面科学，将研究和教育结合起来。

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.