Surface structure and intercalative polymerization studies of smectite clay thin films

摘要

The microstructure of the clay minerals Cu~(2+) exchanged hectorite, Na~+ exchanged hectorite, Na~+ exchanged montmorillonite and Ca~(2+) exchanged montmorillonite were studied using scanning force microscopy (SFM), electron spin resonance (ESR), and x-ray diffraction. The montmorillonite films displayed the rough clay fabric commonly associated with these materials. Ca~(2+) montmorillonite films consisted of a porous web-like grain structure, while Na~+ montmorillonite films were composed of clumps of smaller discrete grains. The lesser studied hectorite films, however, revealed many large, flat regions suitable for further SFM examination and polymerization studies. The chemical reactivity fot he hectorite clays was studied by examining polymerization reactions occurring when the clays were exposed to benzene and aniline. In the case of standard Na~+ exchanged hectorite, little or no reactivity was observed upon exposure to the various monomers. For the Cu~(2+) exchanged hectorite, large scale intergallery and surface polymerization were observed upon exposure to aniline, with intergallery polymerization observed in the case of benzene.