  The capillary forces exerted by liquid drops and bubbles on a soft solid are
directly measured using molecular dynamics simulations. The force on the solid
by the liquid near the contact line is not oriented along the liquid vapor
interface nor perpendicular to the solid surface, as usually assumed, but
points towards the liquid.
  It is shown that the elastic deformations induced by this force can only be
explained if, contrary to an incompressible liquid, the surface stress is
different from the surface energy. Using thermodynamic variations we show that
the the surface stress and the surface energy can both be determined accurately
by measuring the deformation of a slender body plunged in a liquid. The results
obtained from molecular dynamics fully confirm those recently obtained
experimentally [Marchand et al. Phys. Rev. Lett. 108, 094301 (2012)] for an
elastomeric wire.
