Colloidal stabilization and destabilization of a carboxyl latex by adsorption of Triton X-100.

The stability behaviour of a carboxyl latex after adsorption of Triton X-100 has been studied with respect to the surfactant coverage, being the pH an important variable due to the weak character of the surface groups. Three different types of stabilization can be distinguished as a consequence of the relation between the van der Waals attraction energy (V-A) and the steric interaction energy (V-S): electrostatic (V-S = 0), electrosteric (V-S < \V-A\) and steric (V-S > \V-A\) stabilizations. Most of the cases may be explained using the extended DLVO theory. However, at acid pH and low coverage a destabilization phenomena, non-predicted by colloidal stability theories, was found. This encountered fact may be explained by the consideration of a specific interaction between the carboxyl groups and the ethylene oxide chains through hydrogen bonding.