  Hypothesis: A broad range of phenomena, such as emulsification and emulsion
stability, foam formation or liquid evaporation, are closely related to the
dynamics of adsorbing colloidal particles. Elucidation of the mechanisms
implied is key to a correct design of many different types of materials.
  Experiments: Microspheres forced to rotate near a fluid interface exhibit a
roto-translational hydrodynamic mechanism that is hindered by capillary torques
as soon as the particles protrude the interface. Under these conditions, the
time evolution in the ratio of moving spheres provides a direct description of
the adsorption kinetics, while microscopy monitoring of particle
acceleration\deceleration informs about the adsorption\desorption dynamics. In
this work, the proposed strategy is applied at an air/water interface loaded
with spherical magnetic particles negatively charged, forced to rotate by the
action of a rotating magnetic field.
  Findings: The proposed method enables the adsorption/desorption dynamics to
be followed during the earliest phase of the process, when desorption of a
small fraction of particles is detected, as well as to estimate approximated
values of the adsorption/desorption constants. The results obtained show that
the addition of a monovalent salt or a cationic (anionic) surfactant promotes
(inhibits) both adsorption and formation of permanent bonds between particles.
