IR spectroscopy is applied to study polyelectrolyte films of 0.1–5 μm thickness. This approach permits to obtain not only the usual chemical information about polymer conformation, chemical bonds, interacting groups, and molecular/ionic state, but also important structural parameters of the film, such as total thickness, average thickness of each layer, and sparseness of polymer packing. All these information can be obtained from one single sample.
IR cell for thickness measurements of a polyelectrolyte film. The pathlength d of the cell is measured twice: before and after film deposition. The film thickness, Δd = de ? df, can be calculated using the interference maxima that determine values de and df.
