Scanning force microscopy experiments probing micromechanical properties on polymer surfaces using harmonically modulated friction techniques - II. Investigations of heterogeneous systems

Applying a high-frequency lateral vibration between tip and sample in a sca nning force microscope (SFM), a harmonically modulated lateral (friction) f orce image can be obtained using lock-in techniques. Harmonically modulated lateral force microscopy (HM-LFM) offers several advantages compared with standard lateral force microscopy (LFM). After a brief investigation of the scan velocity dependence of LFM and HM-LFM, two samples were investigated. First, the surface of a poly(acrylonitrile-co-styrene)/polybutadiene blend (ABS) was used to demonstrate the ability of the new technique to decrease the stick effects of the SFM tip. Second, an interface between two chemica lly very similar polymers was prepared by melting polypropylene (PP) and po ly(propene-block-ethene) (PP-block-PE) films on each other. After cutting, the surface roughness of this sample was very high. It is shown that only H M-LFM clearly resolves the local micromechanical properties without artefac ts.