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.
Date of this Version
1. R. Roy, R.L. Seiler, J.A. Weibel, and S.V. Garimella, “Droplets on Soft Surfaces Exhibit a Reluctance to Coalesce due to an Intervening Wetting Ridge,” Advanced Materials Interfaces, 2000731, 2020.