Inviscid wetting and spreading by capillarity: the 'walking' instability

点击翻译按钮获取中文摘要

1236582SteenA moving liquid spreads across a solid by displacing the surrounding gas. The recent discovery that, under certain circumstances, the energy stored in the liquid shape can be converted into the energy of liquid motion - as in the droplet "walking instability" - represents a heretofore unknown pathway of energy conversion of potentially vast significance. The objective of this study is to map out the circumstances where this new pathway is operative by developing theoretical stability predictions and by testing these predictions against experiment. The approach that enables achieving our objective is jointly based on fresh mathematical techniques (for prediction) and recent innovative methods to tailor solid surface properties in the lab (for testing). The intellectual merit of this study lies in the new techniques for prediction and those to bring to life the predicted behavior. Broader impacts of this study will accrue for both human resource development and technology. On the side of technology, in the manufacturing arena, immersion lithography for semiconductor processing and casting of wide-format silicon subtrates for solar panel applications stand to benefit while, in the agricultural sciences arena, new paradigms for droplet atomization will enable better localization of pesticide spray while, in the health-care arena, tunable droplet actuation stands to be of benefit to lab-on-chip diagnostic devices. On the side of human resources, female graduate students will be trained as technical leaders through the development of an outreach module that brings the excitement of liquid shape-change motions to high school students and their parents and thereby also works to broaden female participation in the science, technology, engineering and mathematics disciplines.