The motion of liquid droplets in phase separating mixtures depends on
the difference between the concentration of the continuum phase and its
equilibrium value,
,
as well as on convection. Isolated drops immersed in homogeneous
concentration fields grow linearly in size and move randomly, when
> 0;
otherwise, drops shrink and do not move.
The capillary forces induce mutual attraction between two drops.
If
< 0,
the attractive force leads always to coalescence, while when
> 0,
screening effect may keep the drops apart from each other.