  We present a large range of experimental data concerning the influence of
surfactants on the well-known Landau-Levich-Derjaguin experiment where a liquid
film is generated by pulling a solid plate out of a bath. The thickness h of
the film was measured as a function of the pulling velocity V for different
kind of surfactant and at various concentrations. Measuring the thickening
factor $\alpha=h/h_{LLD}$, where hLLD is obtained for a pure liquid, in a wide
range of capillary ($Ca=\eta V/\gamma$), two regimes of constant thickening can
be identified: at small capillary number, $\alpha$ is large due to a
confinement and surface elasticity (or Marangoni) effects and at large Ca,
$\alpha$ is slightly higher than unity, due to surface viscous effects. At
intermediate Ca, $\alpha$ decreases as Ca increases along a "dynamic
transition". In the case of non-ionic surfactants, the dynamic transition
occurs at a fixed Ca, independently of the surfactant concentration, while for
ionic surfactants, the dynamic transition depends on the concentration due to
the existence of an electrostatic barrier. The control of physico-chemical
parameters allowed us to elucidate the nature of the dynamic transition and to
relate it to surface rheology.
