Atomic Force Microscopy

Work of adhesion between the the AFM tip and the surface of a polymer blend sample (PolyStyrene-PolyCapralactone).

We analyze the nonlinear oscillations  of an AFM cantilever to reveal the forces between the tip and the surface. The cantilever is driven with two pure tones near resonance. The nonlinear tip-surface force gives rise to frequency mixing, or intermodulation  of the drive tones. With a multifrequency intermodulation lockin we capture in real-time the amplitude and phase at many intermodulation products as we scan. The method gives multiple amplitude and phase images in one scan, with each image showing rich and varying contrast. We have developed several different algorithms for interpreting the information in these multiple amplitude and phase images, to reconstruct the interaction between the AFM tip and the surface.

Here is a link to a movie  which demonstrates intermodulation as the oscillating AFM tip approaches a surface.

Find our recent publications at this link . You can also find further information on the website of Intermoduation Products .

Links to PhD Theses: Erik Tholén 2009 , Daniel Platz 2013 , Daniel Forchheimer 2015

Page responsible:David B Haviland
Belongs to: Nanostructure Physics
Last changed: Sep 12, 2017