Thermal Marangoni Flow Impacts the Shape of Single Component Volatile Droplets on Thin, Completely Wetting Substrates

Despite surface energies dictating complete wetting, it has been classically observed that volatile alkanes do not spread completely on glass substrates, and faster evaporation rates lead to higher contact angles. Here we investigate how substrate thickness influences this behavior. For sufficiently thin find evaporate slower display apparent angles, at odds with the typical explanations involving just evaporation, capillarity, viscous dissipation. We derive droplet temperature distribution use as part of a criteria show thermal Marangoni contraction plays significant role in establishing shape substrates.