  A novel mechanical approach is developed to explore by means of atom-scale
simulation the concept of line tension at a solid-liquid-vapor contact line as
well as its dependence on temperature, confinement, and solid/fluid
interactions. More precisely, by estimating the stresses exerted along and
normal to a straight contact line formed within a partially wet pore, the line
tension can be estimated while avoiding the pitfalls inherent to the
geometrical scaling methodology based on hemispherical drops. The line tension
for Lennard-Jones fluids is found to follow a generic behavior with temperature
and chemical potential effects that are all included in a simple contact angle
parameterization. Former discrepancies between theoretical modeling and
molecular simulation are resolved, and the line tension concept is shown to be
robust down to molecular confinements. The same qualitative behavior is
observed for water but the line tension at the wetting transition diverges or
converges towards a finite value depending on the range of the solid/fluid
interactions at play.
