Regensburg 2019 – wissenschaftliches Programm
CPP 25.58: Poster
Dienstag, 2. April 2019, 14:00–16:00, Poster B1
Water freezing and frosting on lubricant impregnated surfaces — •Lukas Hauer1,2 and William Wong1 — 1Max Planck Institute for Polymer Research — 2Institute of Fluid Mechanics and Aerodynamics, Technische Universität Darmstadt
In the scope of the present work, frost formation and drop freezing in/on lubricant-infused surfaces ("under-oil" dynamics) are experimentally investigated. Glass substrates structured with SU-8 micropillar arrays are chosen as model surfaces. To examine frost formation, a sample is placed on a Linkam peltier stage which is enclosed in a chamber with humidity control to induce condensation-frosting. To examine freezing, the sample (and deposited drop) is placed in an alternate chamber with temperature control, which is cooled using liquid nitrogen. Frost formation and drop freezing will be observed using an inverted laser scanning confocal microscope. This spatially and temporally resolved technique allows accurate observation of these dynamic processes close to the substrate surface. By adding a dye to the lubricant, the water-lubricant interfaces can be discriminated, allowing us to monitor lubricant mobility during freezing/frosting. During frost formation, a migration of the lubricant to the top of the ice has been observed. Due to the dendritic morphology of frost, capillary effects are believed to be the driving forces of this phenomenon. Such effects could lead to lubricant drainage and failure of surface functionality. A fundamental understanding of the lubricant migration will help to design more ice-durable slippery surfaces.