Temperature distribution over the surface of a thin water droplet on a structured surface at slight underheating

The dynamics of droplet surface temperature was studied for a sessile water droplet on a structured black silicon substrate that was heated to 90°C. The wetting properties of black silicon were analyzed during substrate heating in the temperature range of 30–90°C. IR thermography revealed that nucleation sites form at temperatures close to the boiling point at the liquid–black silicon interface. The dynamics of surface temperature changes for a thin liquid droplet during the final stages of evaporation was also examined, including the formation and subsequent development of bubble nuclei within the droplet. It is shown that convection and bubble formation causes temperature field nonuniformity.