The Intercalation of a Vermiculite by Cationic Surfactants and Its Subsequent Swelling with Organic Solvents

The Structures of Complexes of a Vermiculite Intercalated by Cationic Surfactants, a Mixture of Cationic Surfactants, and a Mixture of Cationic and Nonionic Surfactants

“…• to the clay surface, the angle of tilt that optimizes the binding of the head group to the clay surface and which is the structure that has already been established for the singlesurfactant complexes by us (11) and by others (14,30,31). In this structure the two chains are randomly distributed within the unit cell.…”

“…In a previous paper we have examined the effect of the intercalation of cationic surfactants of different shape and charge into a vermiculite clay mineral (Eucatex vermiculite) and the subsequent swelling of the complex by organic solvents (11). From an examination of the effect of the surfactant on the basal spacing of the clay we concluded that for single nalkyltrimethylammonium bromides about two-thirds of the surfactant is required to neutralize the negative charge on the clay platelets but the remaining third is intercalated in the form of ion pairs.…”

Review of the fundamental geochemical and physical behaviors of organoclays in barrier applications

“…A study by Yu et al (2014) demonstrated that a HDTMA-montmorillonite swelled in xylene, and that the particles were dispersed as hydrophobic interactions between surfactant and xylene prevailed. The study of Williams-Daryn and Thomas (2002) quantified the organo-vermiculite swelling in toluene, and their results indicated that the interlayer spacing increased by N 10 Å when the soil was soaked in toluene.…”

The interlayer swelling and molecular packing in organoclays

“…The swelling of clay minerals, e.g., sodium montmorillonite, upon the exchange of interlayer metal cations with organic surfactant cations (commonly alkyl ammoniums) has been extensively studied since the 1940s [1][2][3][4][5][6][7][8][9][10][11]. It is generally accepted that the extent of swelling depends on the length of the alkyl chain and the cation-exchange capacity (CEC) of the clay.…”