Intercalation of a nonionic surfactant (C₁₀E₃) bilayer into a Na-montmorillonite clay

A nonionic surfactant, triethylene glycol mono-n-decyl ether (C ₁₀E₃), characterized by its lamellar phase state, was introduced in the interlayer of a Na-montmorillonite clay at several concentrations. The synthesized organoclays were characterized by small-angle X-ray scattering in conjunction with Fourier transform infrared spectroscopy and adsorption isotherms. Experiments showed that a bilayer of C₁₀E ₃ was intercalated into the interlayer space of the naturally exchanged Na-montmorillonite, resulting in the aggregation of the lyotropic liquid crystal state in the lamellar phase. This behavior strongly differs from previous observations of confinement of nonionic surfactants in clays where the expansion of the interlayer space was limited to two monolayers parallel to the silicate surface and cationic surfactants in clays where the intercalation of organic compounds is introduced into the clay galleries through ion exchange. The confinement of a bilayer of C₁₀E₃ nonionic surfactant in clays offers new perspectives for the realization of hybrid nanomaterials, since the synthesized organoclays preserve the electrostatic characteristics of the clays, thus allowing further ion exchange while presenting at the same time a hydrophobic surface and a maximum opening of the interlayer space for the adsorption of neutral organic molecules of important size with functional properties.