We measured forces between tiny emulsion droplets by using the magnetic cha
ining technique. Force versus distance profiles were obtained for emulsions
stabilized by Tween 20, Tween 20/BSA (bovine serum albumin) mixtures, and
beta-casein. For emulsions stabilized with Tween 20 alone, we observed clas
sical DLVO behavior. At very large Tween 20 concentration, the force profil
e is clearly deviating from the double-layer repulsion. An interpretation o
f the data is proposed combining classical DLVO with steric-like additional
effective repulsion due to the micellar condensation on the droplet surfac
e. The systems that contain both Tween 20 and BSA qualitatively show the sa
me kind of behavior: the purely electrostatic repulsion is progressively tr
ansformed into a steric one in the presence of BSA. The emulsions stabilize
d by beta-casein obey a different type of behavior: in that case the deplet
ion attraction is found to be of great importance. The data are interpreted
assuming additivity of standard DLVO forces and depletion attraction. The
threshold flocculation force, as a function of the ionic strength, was meas
ured for these systems.