EAGER: A Novel Experiment to Study Interfacial Processes between Droplet and Patterned Surfaces

EAGER：研究液滴与图案表面之间界面过程的新颖实验

• 批准号: 1247512
• 负责人: K. Jimmy Hsia
• 金额: $ 15.13万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-10-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1247512&HistoricalAwards=false
• 关键词: EAGER; Novel; Experiment; Study; Interfacial

Hsia CBET - 1247512The proposed exploratory EAGER project aims at the first quantitative measurement of interfacial interactions between a droplet and a patterned substrate. A novel experimental technique is developed to quantitatively study the interaction forces as a function of the geometry and defect characteristics of the micropatterns. The system provides a quantitative testbed for long-standing theories of interfacial processes such as contact-line pinning under different geometric and chemical conditions for the first time, thus benefitting a huge variety of fields, including solid state physics, surface chemistry, and microfabrication. Intellectual MeritSubstrates with micropatterns, particularly those with a "forest" of micropillars interacting with small-scale droplets, have garnered enormous interest in recent years for their versatility and unusual properties, including wettability, adhesive energy, conductivity or capacitance. These patterns have potential applications in widespread industrial processes that rely on non-wetting surfaces that reject dirt, have low adhesive energy, reject water (e.g. coatings for windshields), resist condensation (e.g. in refrigeration devices), or are useful in pore filtration of gases (e.g. in micro fuel cells). Nevertheless, a quantitative understanding of droplet shapes and dynamics lags behind a large number of proof-of-principle experiments. In particular, very little is known about the effect of pattern and pillar geometry on the dynamics of contact line motion and the forces needed to sustain (or arrest) such motion. The proposed work will apply novel experimental techniques for simultaneous quantitative measurements of droplet shape and contact-line pinning forces, both with a spatial resolution at the single-defect level and capable of fast time resolution. The interaction of isolated defects of defined shape with contact lines has long been the subject of pinning theories, perceived as an idealization of the description of real contact line behavior. With high-speed photography and sensitive force sensors, forces and deformations of droplets and substrates in relative motion will be determined simultaneously by making crucial measurements for an accurate description of dynamical contact angle hysteresis as well as droplet repulsion, fragmentation, and coalescence on hydrophobic surfaces. The experiments can access and analyze a wide range of speeds beyond current experiments, in a regime highly relevant for applications. The proposed EAGER research proposal has the following objectives: (i) to seek an accurate understanding of contact line pinning and depinning from isolated defects, in an experimental system that can serve as a paradigm for defect pinning in broader contexts of interfacial processes; (ii) to acknowledge the effect of defect distribution and defect interaction on the contact line as a whole; (iii) to explore an innovative combination of experimental techniques, promising an improved set of tools for analyzing contact line motion on the microscale.Broader ImpactsThe Broader Impacts of the proposed work include those on the societal, group, and individual scales. The research provides fundamental insight in fields of great societal need: clean water, refrigeration, energy, and advanced manufacturing. The graduate and undergraduate students involved in the project will be trained in the areas of microfabrication, soft lithography, surface patterning, and other processes that are of great importance. The PI will also incorporate research results in existing courses and demonstrations. The PI has plans in place to boost the participation of members from under-represented groups by proactively participating in several on-campus/off-campus programs, including Women in Engineering Program, the Minority Engineering Program, and the McNair Scholar Program.

HSIA CBET -1247512拟议的探索性渴望项目旨在首先定量测量液滴和图案化底物之间的界面相互作用。开发了一种新型的实验技术来定量研究相互作用的作用，这是微图案的几何特征和缺陷特征的函数。 该系统为长期存在的界面过程的理论提供了定量测试床，例如第一次在不同的几何和化学条件下固定的接触线固定，从而使各种各样的领域受益，包括固态物理学，表面化学和微型制作。 具有微生物的知识分子优异成绩，尤其是那些与小型液滴相互作用的“森林”的人，近年来对它们的多功能性和异常特性（包括润湿性，粘合能，电导率或能力）引起了极大的兴趣。 这些模式在广泛的工业过程中具有潜在的应用，这些工​​业过程依赖于拒绝污垢，具有低粘合能，拒绝水（例如挡风玻璃涂层）的非润湿表面，抵抗凝结（例如，在制冷设备中），或在孔隙过滤中有用气体（例如在微燃料电池中）。 然而，对液滴形状和动力学的定量理解落在了大量原则实验后面。 特别是，关于模式和支柱几何形状对接触线运动动力学以及维持（或逮捕）这种运动所需的力的影响，知之甚少。 拟议的工作将应用新颖的实验技术，以同时对液滴形状和接触线固定力进行定量测量，均以单位缺陷水平的空间分辨率以及能够快速分辨率分辨率进行空间分辨率。 长期以来，定义形状与接触线的孤立缺陷与接触线的相互作用一直是固定理论的主题，被认为是对真实接触线行为描述的理想化。 通过高速摄影和灵敏力传感器，将通过对动态接触角滞后以及液滴排斥，碎片和在疏水表面上合并的液滴测量来同时确定液滴和底物的力和变形。 。 在与应用高度相关的政权中，实验可以访问和分析超出当前实验的广泛速度。 拟议的急切研究建议具有以下目标：（i）在一个实验系统中，可以准确了解接触线固定和从孤立的缺陷中钉下来，该系统可以用作范围内的范式，以在互生过程的更广泛背景下固定； （ii）确认缺陷分布和缺陷相互作用对整个接触线的影响； （iii）探索实验技术的创新组合，有望有改进的一组用于分析显微镜上的接触线运动的工具。Broader影响拟议的工作的更广泛影响包括社会，组和各个量表上的工作。 这项研究为社会需求的领域提供了基本见解：清洁水，制冷，能源和先进的制造业。 参与该项目的研究生和本科生将接受微加工，软版印刷，表面图案和其他非常重要的过程的培训。 PI还将将研究结果纳入现有课程和示范中。 PI计划通过积极参与几个校园/校外计划，包括工程课程，少数族裔工程计划和麦克奈尔学者计划，从而促进代表性不足群体的成员的参与。