The effect of simple ionic electrolytes on CNC stability (Fig. 2)
was explored, showing a gradual reduction in the zeta potential
with increasing salt concentration (both Na+ and Ca2+ ions). This
is because the Debye-Huckel screening strength is increased upon
increasing the salt concentration and therefore the Debye length
decreases. This encourages adsorption of ions and ion pairs to the
CNC surface and the increase in adsorption of ions is directly facilitated
by the compression of the double layer. As expected, Ca2+ ions
showed more screening strength than Na+ ions, as seen by a greater
reduction in CNC zeta potential. A similar study on the effect of divalent
counterions on the electrophoretic mobility of sulfate latex
particles showed a reduction in absolute mobility with an increase
in concentration of divalent counterions