Zeta potential is the potential difference between the dispersion
medium and the stationary layer of fluid attached to
the dispersed particle. A value of 25 mV (positive or
negative) can be taken as the arbitrary value that separates
low-charged surfaces from highly charged surfaces. Zeta
potential value signifies to the stability of colloidal dispersions.
Colloids with high zeta potential (negative or
positive) are electrically stabilized, while colloids with low
zeta potentials tend to coagulate or flocculate.