SCANNING FORCE IMAGING OF ORGANIC MULTIMOLECULAR FILMS

Scanning force microscopy (SFM) inspection shows that stearic acid dep osited on a glass slide by evaporation of an organic solvent forms a l ayered structure. Scanning force microscopy images covering areas of a few square micrometres show a stack of bimolecular layers. Molecular resolution images of the layer surface shows ordered hexagonal pattern s extending over areas as large as several unit cells. An accurate ana lysis of several images based on the evaluation of the Fourier transfo rm made it possible to measure the unit mesh constant of the surface l attice with an accuracy of 1%. After samples are annealed slightly abo ve melting temperature, the unit mesh constant decreases significantly , indicating a more compact arrangement of the molecules.