Intercalation of vermiculite in presence of surfactants

Abstract Vermiculite was modified with surfactants in order to enable intercalation of vermiculite layers. Since vermiculite has negative charges on its surfaces, it was expected that cationic surfactant would expand the clay mineral layers more than an anionic surfactant. Nevertheless, negative parts of the anionic surfactants interacted with the positively charged edges of vermiculite and caused to super lattice structure so, unexpectedly the expansion of the layers was determined to be fully collapsed phase of vermiculite. Colloidal and structural properties of vermiculite dispersions were examined in presence of anionic, cationic and nonionic surfactants. The results showed that cationic surfactant covered the surface of the vermiculite with a second layer but the expansion of the clay mineral layer was limited compared to the anionic surfactant. The anionic surfactant produced electrostatic interaction with the positively charged edges of vermiculite and fully expanded the layer structure of the vermiculite.