应航天航空学院Marie-Jean Thoraval教授邀请，清华大学张瑞博士将来访我校并作学术报告。

报告人：张瑞博士

时间：2017年10月29日下午16:00-18:00

地点：航天航空学院教一楼第二会议室

报告题目：Designing Superhydrophobic Surfaces with Rapid Droplet Repelling Ability

报告摘要：

The study on the collision between liquid drops and solid surfaces has a history of over a hundred years, which has significant applications in a wide variety of fields, such as inkjet printing, spray cooling, surface coating, crop dusting, vehicle soiling, aircraft anti-icing, and forensic science. Inspired by many examples in nature, such as lotus leaves, the water strider, butterfly wings, and so on, superhydrophobic surfaces with low adhesion and high mobility are found to have excellent water repellency under drop impact. They have been widely applied in a variety of fields including self-cleaning, dropwise condensation, anti-icing, and thermal management. Two principles are proposed to induce rapid bouncing of impacting droplets: one is to suppress drop adhesion, the other is to reduce the contact time between liquid and solid. Hydrophobic surfaces with closed micro-cells are found to maintain the water-repellent characteristics under high-speed drop impact, due to the “gas spring” effect of the air stored in the micro-cavities, which prevents the sliding motion of liquid. A center-assisted recoil of high-speed droplets is observed on hydrophobic substrates with micro-cavities, with an approximately 40% reduction of contact time. The employment of submillimeter-scale textures were found to induce an internal breakup of high-speed droplets, which decreases the critical Weber number of internal rupture and reduces the contact time by 10%-50%. These findings are expected to be crucial to a fundamental understanding of the rapid collisions between drops and micro-structured surfaces, as well as a valuable strategy to guide the fabrication of novel super water-repellant and anti-icing surfaces.

报告人简介：

Ms. Zhang Rui is currently a PhD student in School of Aerospace, Tsinghua University. She has published papers in journals such as PRE, Langmuir, Soft Matter and Microfluidics & Nanofluidics. Her research interests include the high-speed drop impact dynamics, dropwise condensation, droplet freezing and the design of biomimetic super water-repellent surfaces. She will give a talk on high-speed drop impact dynamics and different strategies in fabricating self-cleaning and water-repellent substrates.