Stability of Sols
Sols are thermodynamically unstable and the dispersed phase (colloidal particles) tend to separate out on long standing due to the Vander Waal's attractive forces. However sols tend to exhibit some stability due to
(1) Stronger repulsive forces between the similarly charged particles
(2) Particle-solvent interactions : Due to strong particle-solvent (dispersion medium) interactions, the colloidal particles get strongly solvated.