First observation of in-plane X-ray diffraction arising from a single layered inorganic compound film by a grazing incidence X-ray diffraction system with a conventional laboratory X-ray source

Grazing incidence angle in-plane X-ray diffraction (in-plane XRD) was applied to characterization of an organic–inorganic hybrid Langmuir–Blodgett (LB) film in a laboratory scale. The hybrid LB film consisted of octadecyl ammonium cation and sodium montmorillonite layers at Si(1 0 0) wafer. The in-plane XRD measurements of the hybrid LB film gave one diffraction peak at 20.0° (0.44 nm), which we assigned to the (1 1 0) and (0 2 0) reflections of montmorillonite. This was the first example of the in-plane diffraction from a single layered montmorillonite, presenting a clear evidence for the parallel orientation of the (0 0 1) plane with respect to a film surface.