Normal and lateral forces in scanning force microscopy

Abstract

With an atomic force/friction force microscope operating in the constant force mode and with an optical lever technique as a deflection sensor, we have investigated the total force acting on the cantilever tip during the raster scanning of the sample surface. A model including the normal and lateral components of the force has been worked out. The normal force is related to the cantilever loading. The lateral force has two components, dissipative and nondissipative, having opposite symmetry with respect to the scanning direction. Within our model, the nondissipative component, which is related to the topography, can be distinguished from the friction component in two different ways, both leading to ‘‘pure friction’’ images. The first method is based on the comparison of two images acquired in the forward and backward scanning direction, respectively. The second method is based on the comparison of the topographic and lateral force images acquired in the same scanning direction. This latter way does not need correction for the nonlinear behavior of the piezoelectric transducer. Results from various samples are reported.

RETRACTED: Local increase in stiffness of agarose gel layer by patterning with polylysine measured via atomic force microscopy

“…This difference is calculated to remove the effect of the derivative of topography, which is mirrored in the individual lateral force images, and gives a direction independent contribution. The difference maintains only the actual lateral force due to friction, which is direction dependent, instead (Ascoli et al, 1994).…”

Improved estimation of contact compliance via atomic force microscopy using a calibrated cantilever as a reference sample

“…2b, where the combination of lateral force measured on the two opposite scans is shown, calculated as (forward-backward)/2. According to this calculation the friction component of the lateral force, which is changed in sign on inverting the motion, is averaged, whereas the geometrical component, which is the derivative of the topography, is canceled out [34]. From the cross section in Fig.…”

Atomic force microscopy and lateral force microscopy using piezoresistive cantilevers

“…[9][10][11] For this purpose a probe was designed to perform both topography mapping and imaging of the mechanical properties simultaneously. [9][10][11] For this purpose a probe was designed to perform both topography mapping and imaging of the mechanical properties simultaneously.…”