Temperature Dependence of Surface Energy of Ice and its Implications on Adhesion and Friction

冰表面能的温度依赖性及其对粘附和摩擦的影响

• 批准号: 2102578
• 负责人: Ali Dhinojwala
• 金额: $ 50万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2102578&HistoricalAwards=false
• 关键词: Temperature; Dependence; Surface; Energy; Ice

With support from the Chemical Structure, Dynamics and Mechanisms-A Program (CSDM-A) program in the Division of Chemistry, Professor Ali Dhinojwala of The University of Akron is investigating the temperature dependence of the surface energy of ice and how it influences adhesion and friction. As the surfaces of ice are covered with a water-like surface layer, this is expected to impact the surface energy, adhesion, and friction. Professor Dhinojwala and his students are using advanced spectroscopy techniques to study the contact interface between ice and a soft elastomer and how the structure of this interface changes with temperature. Their work will shed light on the transition temperature of the liquid-like layer of water and its influence on the surface energy of ice. Their discoveries could lead to the design of new materials or coatings for higher traction on ice such as winter tires and shoe soles; for ice-resistant surfaces and anti-icing coatings on aircraft, high voltage cables, and wind turbine blades; and materials to improve food preservation. Dr. Dhinojwala is promoting STEM (science, technology, engineering and mathematics)-related outreach activities as a Director of District Science Day and the co-director of the Biomimicry Center, and he is designing an honors class on materials that have influenced human civilization. This project seeks to reveal the molecular level details of an observation made by Professor Dhinojwala and his students, namely an abrupt transition in adhesion energy between a siloxane elastomer and an ice surface at 257 K (16 K below the bulk melting temperature of ice). Dhinojwala and his team hypoethesize that this change in adhesion energy is due to an abrupt transition of the bilayer of ice and potentially a change in the surface energy of the ice. Because both adhesion and friction will also be influenced by this transition, Dhinojwala’s research team is using the Johnson–Kendall–Roberts geometry to measure the thermodynamic work of adhesion and compare it to the temperature dependence of surface energy. The team is using a new interface-sensitive sum frequency generation spectroscopy (SFG) technique to study the contact interface between ice and soft elastomers, a problem of fundamental importance in understanding adhesion and friction of ice surfaces. Dhinojwala’s team is applying these measurements to study the influence of roughness and correlate with Persson’s predictions on how ice adhesion and friction are affected by roughness. The broader impacts of this research in technological applications stem from new insights that relate interfacial molecular structure to macroscopic friction coefficients.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系化学结构，动力学和机制计划（CSDM-A）的支持下，阿克伦大学的Ali Dhinojwala教授正在研究冰表面能的温度依赖性以及它如何影响粘附力和摩擦力。由于冰的表面覆盖着水状的表面层，这预计会影响表面能，粘附力和摩擦力。Dhinojwala教授和他的学生正在使用先进的光谱技术来研究冰和软弹性体之间的接触界面，以及该界面的结构如何随温度变化。他们的工作将揭示液态水层的转变温度及其对冰表面能的影响。他们的发现可能会导致设计新的材料或涂层，以提高冰上牵引力，如冬季轮胎和鞋底;用于飞机，高压电缆和风力涡轮机叶片的抗冰表面和防冰涂层;以及改善食品保存的材料。Dhinojwala博士作为地区科学日主任和仿生中心的联合主任，正在推动STEM（科学，技术，工程和数学）相关的外展活动，他正在设计一个关于影响人类文明的材料的荣誉课程。该项目旨在揭示Dhinojwala教授和他的学生所做的观察的分子水平细节，即硅氧烷弹性体和冰表面之间的粘附能在257 K（低于冰的整体熔化温度16 K）下突然转变。 Dhinojwala和他的团队假设，粘附能的这种变化是由于双层冰的突然转变以及冰表面能的潜在变化。由于粘附力和摩擦力也会受到这种转变的影响，因此Dhinojwala的研究团队正在使用Johnson-Kendall-Roberts几何来测量粘附力的热力学功，并将其与表面能的温度依赖性进行比较。该团队正在使用一种新的界面敏感和频发生光谱（SFG）技术来研究冰和软弹性体之间的接触界面，这是理解冰表面粘附和摩擦的一个重要问题。Dhinojwala的团队正在应用这些测量结果来研究粗糙度的影响，并与Alfreson关于冰的粘附力和摩擦力如何受到粗糙度影响的预测相关联。这项研究在技术应用方面的广泛影响源于将界面分子结构与宏观摩擦系数联系起来的新见解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。