earticle

영어

Ultra-thin liquid films on solid substrates in contact with the saturated vapor are studied by using molecular dynamics simulation. The properties of evaporation and condensation of the films of various adsorptive strengths and thicknesses are obtained during the quasi-steady film evolution. Net condensations occur when the ultra-thin films on the high energy surface come into contact with the saturated vapor phase because the normal film pressure stays lower than the saturated vapor pressure. The net condensation rate is higher for the material combination of higher adsorptive strength. It becomes more so when the film thickness is of a lesser size. On the other hand, that of lower adsorptive strength has lower net condensation rate and depends less on the film thickness. Therefore, the size effect of the condensation phenomenon is more significant for the system of a higher adsorptive strength. This properties come from the state of ultra- thin film, which can be quantified by using disjoining pressure in the quasi-steady processes. These results have implications in practical problems concerning the moving contact line when the precursor film formation is critical.