Influence of the substrate thermal properties on sessile droplet evaporation: Effect of transient heat transport

When using most models of new energy saving dish-washers, one annoying thing happens: plastic dishes remain still wet after the drying cycle, whereas ceramic dishes or metal cutlery are well dry. To start understanding the different drying behavior of different materials, we conducted sessile drop evaporation experiments on substrates with dissimilar thermal conductivity, but similar wettability. A total of 30 evaporation experiments with pure water drops of different sizes were conducted and analyzed. We found that the thermal properties of the substrate have a strong influence on evaporation time of a sessile droplet. A numerical model describing transient heat conduction in the drop and in the substrate as well as vapor diffusion in the gas has been developed. The numerical predictions of drop evolution show a good agreement with experimental data.