Colloid chemical characterisation of layered titanates, their hydrophobic derivatives and self-assembled films

Na₂Ti₃O₇, with layered structure, was prepared from a 1:3 molar mixture of powdered Na₂CO₃ and TiO₂ by heating at 800 °C for 2 h. The Na⁺ ions were exchanged for H⁺ ions by hydrochloric acid treatment; next, n-butylamine, n-octylamine, n-decylamine or n-dodecylamine were incorporated at pH=3.6–3.8. It was proven by XRD measurements that, as the length of the alkyl chain of the amines was increased, smaller amounts of amines were intercalated under identical conditions. H₂Ti₃O₇ samples dispersed in liquids of various compositions and polarities were used for the preparation of self-assembled titanate/polymer films for further sensor applications. Titanates, their composites with alkyl amines and the self-assembled hybrid structures were characterized by X-ray diffraction, thermoanalytical, optical, electron and atomic force microscopic measurements.