Cantact angle hysteresis
Abstract: Wetting of a solid surface by a liquid is quantified by the advancing and receding contact angles. Theadvancing contact angle is always larger than the receding contact angle. The difference between the two iscalled contact angle hysteresis. Contact angle hysteresis influences our daily life. It, for example, preventsfrictionless sliding of sessile drops. Sliding without resistance may be an advantage to keep windows,windscreens or glasses clean, but it would make many applications such as printing or coating extremely difficult.From the fundamental point of view, contact angle hysteresis prohibits us from measuring the equilibrium contactangle and thus impedes and easy link to theory via Young's equation. In the presentation, effects leading to contactangle hysteresis will be discussed including some effects, which have only been realized recently, such as adaption.Contact angle hysteresis is directly linked to the mobility of sessile drops on surfaces. Therefore, sliding ofdrops on super liquid-repellent and lubricant infused surface will be analyzed. About the Speaker: Prof. Hans-Jürgen Butt is a director at the Max Planck Institute for Polymer Research, Mainz, Germany.He studies the structure and dynamics of interfaces. The aim is to better understand the relationship betweenstructural changes, dynamics, and the driving forces. Major topics are interfacial forces .and wetting, in particularwetting of superamphiphobic surfaces. His group investigates liquids that are internally structured at dfferentlength scales, such as polymer melts, solutions, dispersions, or emulsions. He published more than 450 papersincluding papers in Science, Nature sister journals, PRL, Adv Mater, JACS, Angew Chem Int Ed. He wasawarded ERC Advanced Grant and elected as president of IACIS (International Association of Colloid andInterface Scientists).