Barium stearate Langmuir–Blodgett films investigated by mapping adhesion forces with atomic force microscopy

Barium stearate (BS) Langmuir–Blodgett monolayers have been deposited onto plasma oxidised silicon substrates. The films, aged in air at room temperature for several days, show relatively large holes. Height, friction and adhesion maps have been obtained in air by atomic force microscopy (AFM) on these aged films. The height and friction maps are in agreement with a picture in which BS molecules are assembled on the surface almost orthogonally. A point-by-point correspondence between morphological, friction and adhesion maps was found. Time-of-flight secondary ion mass spectrometry chemical maps have been obtained in order to confirm the AFM results.