Relationship between Q-factor and Sample Damping for Contact Resonance AFM Measurement of Viscoelastic Properties
Donna C. Hurley, Philip Yuya, Joseph Turner
Contact resonance atomic force microscopy (CR-FM) techniques rely on the dynamics of the AFM cantilever as it vibrates while in contact with the sample of interest. In this letter, we highlight the importance of modeling the dynamics of a cantilever beam accurately for measurements involving viscoelastic samples. In particular, the dependence of the quality factor of the vibration modes on the sample properties is shown to be a complex combination of beam and sample properties as well as the applied static tip force. Thus, the quality factor alone cannot be used to infer the sample damping directly. The nonlinear relation between quality factor and sample damping is examined for several different factors, the most important of which is the applied tip load. We show how the model can be used to analyze CR-FM measurements of quality factor and resonance frequency to obtain stiffness and damping properties. Experimental results for polystyrene and polypropylene samples are found to be in good agreement with the model predictions. Our results form the basis for mapping viscoelastic properties with nanoscale spatial resolution.
, Yuya, P.
and Turner, J.
Relationship between Q-factor and Sample Damping for Contact Resonance AFM Measurement of Viscoelastic Properties, Journal of Applied Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=907205
(Accessed March 1, 2024)