MRI-R2: Developing Instrumentation for measuring decoupled normal and lateral retention forces for systems of drops on surfaces

MRI-R2：开发用于测量表面液滴系统的解耦法向力和横向保持力的仪器

• 批准号: 0960229
• 负责人: Rafael Tadmor
• 金额: $ 11.93万
• 依托单位: Lamar University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0960229&HistoricalAwards=false
• 关键词: MRI; R2; Developing; Instrumentation; measuring

0960229Tadmor"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Tribology teaches that the lateral force required to slide two surfaces against each other (friction force) is in fact proportional to the contact area. The Amonton law, therefore, is a special case in which the contact area of a rough surface happens to increase linearly with the load. The PI recently presented a system in which the lateral force decreases with the normal force in spite of the fact that the contact area increases. This happens for drops on surfaces, and the discovery was enabled using an instrument that allowed for the first time some limited decoupling between normal and lateral retention forces, namely the Centrifugal Adhesion Balance (CAB). In this proposal the PI will develop the CAB such that it will enable for the first time complete independent manipulations of the normal and lateral retention forces, which is essential for the study of the dependence of lateral retention forces on the normal forces. Enabling the measurement will change the way we consider the mutual influence of orthogonal retention forces. This will create a new paradigm in surface science (aiming to find relation between normal and lateral retention forces) leading to transformative research. Another feature that this will add to the CAB is the possibility to decrease the normal force under zero lateral force. In this configuration the drop can only move normal to the surface, and will eventually fly off the surface at some negative normal force. Such an experiment will be the first experimental direct test for the Dupre equation - a central issue in surface science - thereby bearing the potential to radically change our understanding of the Young-Dupre equation thereby leading again to a transformative research. This instrument will be used to study drops on surfaces and also any other case in which two orthogonal retention forces may influence each other.

0960229Tadmor“该奖项是根据 2009 年美国复苏和再投资法案（公法 111-5）资助的。”摩擦学告诉我们，两个表面相互滑动所需的横向力（摩擦力）实际上与接触面积成正比。因此，阿蒙顿定律是一种特殊情况，其中粗糙表面的接触面积恰好随载荷线性增加。 PI 最近提出了一种系统，尽管接触面积增加，但侧向力随法向力减小。这种现象发生在表面上的液滴上，而这一发现是通过使用一种仪器实现的，该仪器首次允许法向保持力和横向保持力之间的有限解耦，即离心粘附天平（CAB）。在本提案中，PI 将开发 CAB，使其首次能够完全独立地操纵法向保持力和横向保持力，这对于研究横向保持力对法向力的依赖性至关重要。启用测量将改变我们考虑正交保持力相互影响的方式。这将在表面科学领域创建一个新的范式（旨在找到法向保持力和横向保持力之间的关系），从而带来变革性的研究。这将为 CAB 添加的另一个功能是可以在零侧向力下减小法向力。在这种配置中，水滴只能垂直于表面移动，并且最终会在某些负法向力的作用下飞离表面。这样的实验将是对杜普雷方程（表面科学的一个核心问题）的首次实验直接测试，从而有可能从根本上改变我们对杨-杜普雷方程的理解，从而再次带来变革性的研究。该仪器将用于研究表面上的跌落以及两个正交保持力可能相互影响的任何其他情况。