Intercalation of a cationic azobenzene into montmorillonite

The intercalation of a cationic azobenzene derivative into the interlayer space of montmorillonite has been achieved by ion exchange between sodium-montmorillonite and p-(ω-dimethyl-hydroxyethylammonioethoxy)-azobenzene bromide. X-ray diffractometry and elemental analysis indicated that the dye cations were intercalated. The microstructures of the montmorillonite-dye intercalates were controlled by the amount of dye loaded as evidenced by the variation in basal spacings and visible absorption spectra of the materials. The intercalated azo dyes exhibit reversible trans-to-cis photoisomerization under UV and visible light irradiation.