Microscale interactions with deformable substrates are of fundamental interest for studying self‐assembly processes and the mobility of cells on soft surfaces, with applications in traction force microscopy. The behavior of microscale water droplets on a soft polymer substrate is investigated. Droplets formed by condensation on the soft substrate are reluctant to coalesce, which leads to coverage of the surface with clusters of droplets assembled in a honeycomb‐like pattern. Cryogenically fixed in this state, scanning electron microscopy of these droplets reveals the presence of an intervening wetting ridge of the polymer that acts as a barrier between neighboring droplets and prevents coalescence. A linear elastic deformation model is developed to predict this surface profile and corroborate the observed behavior.
It is an everyday observation that water droplets condensing on a rigid substrate coalesce immediately upon touching. Soft surfaces, however, possess unique properties that create an illusionary effect in this situation, making it appear that droplets can touch and form a dense pattern instead of coalescing. In article number 2000731 Rishav Roy, Suresh V. Garimella, and coworkers demonstrate that this reluctance to coalesce is a consequence of deformation of the soft surfaces to form intervening ridges between the droplets. The cover art illustrates the topography of droplet ‘footprints’ after they are removed from a cryogenically fixed soft substrate.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.