Optimization of experiment in scanning force microscopy of polymers

A scanning force microscopy (SFM) study of an oriented polyethylene (PE) tape and a microporous isotactic polypropylene (iPP) film was conducted in the contact and tapping mode. In sub-water measurements on polymer surfaces with minimal tip-sample interactions, the images obtained in both modes correctly reproduce surface morphology and nanostructure. An advantage of the tapping mode in non-destructive imaging was shown in the observation of a weakly bound skin layer on the PE tape. This layer is destroyed during scanning with higher forces; however, its removal allows one to examine the core nanostructure of this material. Ambient-condition SFM measurements in both modes are accompanied by stronger tip-sample interactions. This leads to an overestimation of the dimensions of surface features and to a larger contribution of surface hardness to the image contrast.