UNS: Molecular Modeling of Wetting and Dewetting Transitions on Nanotextured Surfaces

1511437-贴片表面粗糙度或纹理可放大疏水或“憎水”表面的理想特性。这种超疏水表面由于具有拒水、自清洁和抵抗生物膜形成的能力而有许多应用。然而，这些革命性材料的广泛采用受到了这样一个事实的阻碍，即超疏水性是脆弱的，如果水渗入表面纹理，就会被摧毁。因此，充分实现这些材料的前景需要稳定脆弱的超疏水状态的策略。这项工作将利用专门的分子模拟方法来提高对表面形貌和超疏水状态稳定性之间的联系的理解，并改变设计坚固的超疏水表面的能力。所提出的工作旨在建立对纳米织构表面的润湿-去湿转变的热力学如何受表面纳米结构的形态影响的理解，并利用这一理解来指导设计坚固的超疏水和超疏油表面。虽然已经用宏观界面热力学对纹理表面的润湿-去湿转变进行了广泛的研究，但对这种转变如何受到集体水密度波动的影响还缺乏基本的理解。我们的工作有望开辟新的天地，通过使用分子模拟来表征纳米结构表面这种润湿-去湿转变的自由能量学，以及相应的机制路径，以及它们对外部条件(如压力)的依赖。这项工作的结果也可能有助于揭示纳米结构表面上的润湿-去湿转变是重要的其他现象，例如气泡的异质成核和接触线钉扎。通过揭示表面纳米结构和超疏水CASSIE态稳定性之间的基本联系，这项拟议的工作有可能为坚固的超疏水和超疏油表面的合理设计提供信息，并对这些材料在实际应用中的使用带来革命性的影响，这些应用范围从自清洁涂料和涂料到防水汽车挡风玻璃，以及飞机机翼和太阳能电池的防冰涂层。拟议的工作将导致培训一名博士生，并将促进国际学生协会对代表不足的少数群体和本科生的指导。该项目的调查结果也将作为加强宾夕法尼亚大学PI正在开发的一门新课程的基础。

1511437 - PatelSurface roughness or texture can amplify the desirable properties of hydrophobic or "water-hating" surfaces. Such superhydrophobic surfaces have numerous applications due to their ability to repel water, to be self-cleaning, and to resist the formation of biofilms. However, the widespread adoption of these revolutionary materials has been thwarted by the fact that superhydrophobicity is fragile, and can be destroyed if water penetrates the surface texture. Thus, fully realizing the promise of these materials requires strategies to stabilize the fragile superhydrophobic state. The work proposed here will employ specialized molecular simulation methods to improve understanding of the connection between surface topography and the stability of the superhydrophobic state, and transform the ability to design robust superhydrophobic surfaces.The proposed work seeks to establish an understanding of how the thermodynamics of wetting-dewetting transitions on nanotextured surfaces are affected by the morphology of the surface nanotexture, and to use this understanding to inform the design of robust superhydrophobic and superoleophobic surfaces. Although wetting-dewetting transitions on textured surfaces have been studied extensively using macroscopic interfacial thermodynamics, a fundamental understanding of how such transitions are affected by collective water density fluctuations is missing. Our work promises to break new ground by using molecular simulations to characterize the free energetics of such wetting-dewetting transitions on nanotextured surfaces, the corresponding mechanistic pathways, and their dependence on external conditions such as pressure. The results of the work could also shed light on other phenomena where wetting-dewetting transitions on nanotextured surfaces are important, e.g., heterogeneous nucleation of bubbles and contact line pinning. By uncovering the fundamental connection between surface nanotexture and the stability of the superhydrophobic Cassie state, the proposed work has the potential to inform the rational design of robust superhydrophobic and superoleophobic surfaces, and bring about a transformative effect on the use of these materials in real-world applications that range from self-cleaning paints and coatings to water-repellent automobile windshields, and ice-resistant coatings for airplane wings and solar cells. The proposed work will lead to the training of a doctoral student and will also facilitate the mentoring of under-represented minority and undergraduate students by the PI. The findings of this project will also serve as the basis for augmenting a new course being developed by the PI at the University of Pennsylvania.