A method for atomic force microscopy cantilever stiffness calibration under heavy fluid loading
Abstract
This work presents a method for force calibration of rectangular atomic force microscopy
(AFM) microcantilevers under heavy fluid loading. Theoretical modeling of the thermal
response of microcantilevers is discussed including a fluid-structure interaction
model of the cantilever-fluid system that incorporates the results of the fluctuation-dissipation
theorem. This model is curve fit to the measured thermal response of a cantilever
in de-ionized water and a cost function is used to quantify the difference between
the theoretical model and measured data. The curve fit is performed in a way that
restricts the search space to parameters that reflect heavy fluid loading conditions.
The resulting fitting parameters are used to calibrate the cantilever. For comparison,
cantilevers are calibrated using Sader's method in air and the thermal noise method
in both air and water. For a set of eight cantilevers ranging in stiffness from 0.050
to 5.8 N/m, the maximum difference between Sader's calibration performed in air and
the new method performed in water was 9.4%. A set of three cantilevers that violate
the aspect ratio assumption associated with the fluid loading model (length-to-width
ratios less than 3.5) ranged in stiffness from 0.85 to 4.7 N/m and yielded differences
as high as 17.8%. (C) 2009 American Institute of Physics. [doi:10.1063/1.3263907]
Type
Journal articlePermalink
https://hdl.handle.net/10161/3371Published Version (Please cite this version)
10.1063/1.3263907Citation
Kennedy,Scott J.;Cole,Daniel G.;Clark,Robert L.. 2009. A method for atomic force microscopy
cantilever stiffness calibration under heavy fluid loading. Review of Scientific Instruments
80(12): 125103-125103.
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