AN EVALUATION OF THE USE OF THE ATOMIC FORCE MICROSCOPE FOR STUDIES IN NANOMECHANICS

The advantages and limitations of using the AFM for studies of materials properties on a small scale is discussed. Alternate analysis methods for calculating interfacial energies from AFM force versus tip-surface distance curves are compared. These values have been calculated in the past by relying only on the maximum pull-off force. Uncertainty regarding the chemical nature and physical structure of the tip at the atomic scale makes such estimates unreliable. It is shown that integrating the experimental force versus distance data to estimate adhesive energy can provide additional information on the nature of the contact. This simple approach has been applied to several published experiments. The results show that in most cases failure of the adhesive bond between tip and flat is mediated by a contaminant layer.