Thin film deposits of cellulose on an inorganic substrate provides an excellent model surface to explore molecular level phenomena taking place during various processes involving cellulose. Examples include interactions of soaps, detergents, perfumes, and softeners with cellulose fibers. The thickness, roughness, and density of these films are all important parameters for studying such controlled processes.
Figure 1 shows the X-ray reflectivity (XRR) data from a cellulose thin film sample collected on Rigaku's Ultima IV multipurpose diffraction system. The results of a non-linear least squares fit of a model structure to the experimental data are shown in Figure 2. The automatic fitting process refines the thickness, roughness, and density values of the model structure until a good fit to the experimental data is achieved. When the fit is good the final values of the thickness, roughness, and density of the model structure can then be attributed to the actual sample.