ABSTRACT

This chapter shows that the coulombic attraction theory potential is much better adapted to explain the experimental phenomena than the DLVO theory potential. The thermodynamic stability of the colloidal gel state has a perfectly natural explanation in terms of the coulombic attraction theory. The addition of a short-range van der Waals potential to UmnG has the effect of bringing the primary minimum into balance with the secondary minimum, and a phase transition between the states becomes possible. The exact interaction potential between n-butylammonium-substituted clay plates or other charged colloidal particles in solution must incorporate many effects, such as the size of the small ions and the molecular degrees of freedom of the solvent, that are beyond the scope of either the coulombic attraction theory or DLVO theory. However, whatever the complicated functional dependence, the curve comprises two states of equal thermodynamic potential.