Abstract below

Pr. Satish Kumar

Department of Chemical Engineering and Materials Science
University of Minnesota, USA

Droplet dynamics near topographical features

While solid substrates are often idealized as being perfectly smooth, all real surfaces possess some level of topographical and chemical heterogeneity. This heterogeneity can greatly influence droplet dynamics, and is of tremendous relevance for applications ranging from oil recovery to water harvesting to advanced manufacturing.
In this talk, we will show how mathematical models based on lubrication theory that account for surface topography provide insight into how topographical features induce pinning of the three-phase contact line where the liquid, air, and solid all meet. Sufficiently strong external forces cause contact-line depinning, and in some cases the depinning force can be understood through relatively simple scaling relationships. Three examples will be presented involving (i) shear-induced depinning, (ii) gravity-induced depinning, and (iii) evaporation-induced depinning. Comparisons to existing experimental observations will be discussed.