To clarify the structure and species of rhodamine 6G (R6G) aggregates formed in taeniolite (TN) interlayer spaces, the oriented thin films of R6G-TN hybrid materials were prepared and analyzed. XRD investigations of these films indicated that the R6G molecules were intercalated in the TN interlayers and that the TN layers were parallel to the glass plate in the thin films. Most of the intercalated R6G molecules were assumed to form various kinds of H-type aggregates in the TN interlayer spaces, since the R6G-TN hybrid films exhibited no emission spectrum by excitation at λ ) 530 nm. The peak-deconvolution results of the UV/vis absorption spectra of the hybrid films indicated that there was one kind of H-type R6G dimer in the thin film. Moreover, polarized UV/vis spectroscopy revealed the existence of high-order aggregates in addition to these dimers. The high-order aggregates, but not the dimers, were found to be aligned perpendicularly to the TN surface in the TN interlayer spaces.

To develop the solid-state laser oscillator based on laser dye compounds, the incorporation of rhodamine 6G (R6G, a laser dye) in cetyltrimethylammonium (CTA+) cationic surfactant/montmorillonite clay hybrid (HpC) thin solid films was investigated. The R6G/HpC samples were prepared by immersing the HpC films into a R6G aqueous solution with various concentration. X-ray diffraction patterns of the films of HpC, measured before and after the intercalation of R6G, proved the coexistence of both the dye and surfactant in clay interlayer spaces. All prepared thin films exhibited luminescence. It indicates that CTA+ molecules play a role as a partial suppressor of the aggregation of R6G molecules which prevents fluorescence. Moreover, the luminescence property of the present thin films was observed to be dependent on the co-intercalated degree of R6G molecules, indicating that the R6G intercalating in HpC interlayer space molecules exist as two or more luminescence species in the clay interlayer space.

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A structural investigation of composite films of self-assembling stearate ions (C18) in layered double hydrotalcite clay (LDH) was carried out by means of X-ray diffraction (XRD) analysis, gas chromatography (GC), elemental analysis, thermogravimetry (TG), differential thermal analysis (DTA), and inductive coupled plasma emission spectrometric analysis (ICP-AES). From these detailed characterization studies, it was found that C18 forms a well-aligned bilayer structure within the inorganic LDH layers absorbed by the H2O monolayers with a tilt angle of approximately 29° from the right angle of the layers. Moreover, two-dimensional XRD analysis shows the guest anions to be arranged in a distorted hexagonal packing orientation along the lateral axis.

Poly(ethylene terephthalate) (PET) films with a moth-eye-like surface are coated with TiO(2) particles to form self-cleaning antireflective films. The use of a TiO(2) suspension of high concentration to coat the PET surface produces a thicker TiO(2) layer with smaller pores, whereas a low concentration of a TiO(2) suspension gives a thinner layer of TiO(2) with larger pores. The PET films coated with TiO(2) particles exhibit a high transmittance of 76-95% and almost no absorption in the range of 400-800 nm. The PET films coated with a TiO(2) suspension with a concentration of ≥2 vol % exhibit superhydrophilicity after irradiation with UV light. After irradiation, the superhydrophilic nature is retained for at least 18 days. The TiO(2)-coated PET films showed the ability to decompose methylene blue under UV irradiation.

The self-assembly of sodium stearate and its homologs ( >C12) in hydrotalcite (LDH) interlayers was found to change reversibly between mono- and bilayer structures with a ratio changing continuously within a range of 70 °C and 5 °C in stoichiometric intercalations in aqueous dispersion. The bilayer structure was more stable than the monolayer, judging from the fact that bilayer aggregations were formed even in high temperatures with the addition of excess amounts of guest stearates over the anion exchange capacity (AEC). Hydrophobic interaction was determined to be the key factor for the formation of a bilayer assembly.

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