Thickness and roughness measurements in poly(o-methoxyaniline) layer-by-layer films using AFM

Atomic force microscopy (AFM) was employed to monitor the buildup of layer-by-layer films of poly(o-methoxyaniline) (POMA) and poly(ethenesulfonic acid) (PVS) onto several substrates. Using the contact mode of an AFM, we produced a furrow on the film, which was made possible because the film material was less stiff than the substrate and the silicon tip. Film thickness could then be measured using the tapping mode. The thickness and adsorbed amount of POMA/PVS increased linearly after several bilayers had been deposited, while the roughness increased with the number of bilayers until reaching a saturation value. This behavior was attributed to the ability of these polymers to aggregate, which was confirmed by an analysis of grain sizes