ABSTRACT
Another possibility is to use the so-called dynamic mode AFM operated in the frequency modulation mode (FM-AFM). Schirmeisen et al. [104] measured metalpolymer adhesion properties by dynamic force spectroscopy with functionalisation of the tip by a thin layer of aluminum, while the polymer was plasma-etched. They found that plasma etching of the polymer resulted in strongly enhanced interactions, indicating a chemical activation of the polymer surface. Sokolov et al. [105] analyzed the possibility of using noncontact atomic force microscopy to detect variations in surface composition, i.e., to obtain a 'spectroscopic image' of the sample. The authors concluded that long-range forces acting between the AFM tip and the sample depended on the composition of both tip and sample. They showed theoretically how van der Waals forces could be utilized for force spectroscopy. Various results have been achieved in detecting the van der Waals interactions by use of molecular dynamics (MD) simulations and AFM measurements [106-108].
