The sequential intercalation of three types of surfactants into sodium montmorillonite

Abstract Cetyl trimethylammonium bromide (CTAB), a cationic surfactant, sodium dodecyl sulfate (SDS), an anionic surfactant, and hydrogenated castor oil (HCO), a nonionic surfactant, were sequentially intercalated into sodium montmorillonite (Mt). The basal spacing of Mt increased to 5.68 nm after the intercalation of CTAB and SDS. In addition, both FTIR analyses and molecular simulation confirmed the presence of these different types of surfactants in the Mt interlayer. Although the basal spacing decreased to 4.14 nm with the additional intercalation of HCO, the order and stability of the surfactants in the Mt interlayer increased. Thus, a high contact angle and good rheological property were achieved by the highly ordered surfactant arrangements.