Exfoliation and film preparation of a layered titanate, Na ₂Ti₃O₇, and intercalation of pseudoisocyanine dye

Fine powders of propylammonium-exchanged Na₂Ti₃O ₇ were successfully converted to transparent thin films by swelling (and exfoliating) the material in water and subsequent casting and drying the obtained titanate sol on a substrate. The dispersion of the material was promoted by sonication and hydrothermal treatment of the sol. A self-standing film was also obtained by depositing the sol on a Teflon substrate and subsequent peeling off from the substrate by soaking in acetone. Taking advantage of the cation exchange capability of the films thus obtained, a cationic cyanine dye (pseudoisocyanine) was intercalated with retaintion of the transparency and morphology of the films. Polarized visible spectra revealed that the intercalated dyes were present as J-aggregates with the dipole moment oriented parallel to the film surface. The present methodology is a convenient way to fabricate titanate-dye hybrids as films.