Article révisé par les pairs
Résumé : The present theoretical study is concerned with evaporation-induced apparent contact angles for a perfectly wetting one-component liquid placed on a flat solid substrate and undergoing diffusion-limited evaporation into ambient air. The analysis pertains to a distinguished small vicinity of the contact line (the "microregion"), where such angles are established and where various microscopic effects typically enable relaxing the well-known evaporation-flux singularity. We proceed from a Joanny-Hervet-de Gennes-type approach, involving the spreading coefficient, disjoining pressure in the form of an inverse cubic law, and a truncated microfilm (precursor film) starting abruptly at a solid surface. A more classical regime with an (infinitely) extended adsorbed microfilm is recovered therefrom in the limit of large spreading coefficients upon additional incorporation of the Kelvin effect (dew point shift due to the liquid-gas pressure difference). The latter regime is critically revisited with a view to clarifying the scaling prefactor known in the literature. The influence of the kinetic resistance to evaporation is analyzed as well.