Numerical study of the hydrodynamic drag force in atomic force microscopy measurements undertaken in fluids

Teresa Alonso Rasgado, J. V. Méndez-Méndez, M. T. Alonso-Rasgado, E. Correia Faria, E. A. Flores-Johnson, R. D. Snook

    Research output: Contribution to journalArticlepeer-review

    Abstract

    When atomic force microscopy (AFM) is employed for in vivo study of immersed biological samples, the fluid medium presents additional complexities, not least of which is the hydrodynamic drag force due to viscous friction of the cantilever with the liquid. This force should be considered when interpreting experimental results and any calculated material properties. In this paper, a numerical model is presented to study the influence of the drag force on experimental data obtained from AFM measurements using computational fluid dynamics (CFD) simulation. The model provides quantification of the drag force in AFM measurements of soft specimens in fluids.The numerical predictions were compared with experimental data obtained using AFM with a V-shaped cantilever fitted with a pyramidal tip. Tip velocities ranging from 1.05 to 105. μm/s were employed in water, polyethylene glycol and glycerol with the platform approaching from a distance of 6000. nm. The model was also compared with an existing analytical model. Good agreement was observed between numerical results, experiments and analytical predictions. Accurate predictions were obtained without the need for extrapolation of experimental data. In addition, the model can be employed over the range of tip geometries and velocities typically utilized in AFM measurements. © 2014 Elsevier Ltd.
    Original languageEnglish
    Pages (from-to)37-46
    Number of pages9
    JournalMicron
    Volume66
    DOIs
    Publication statusPublished - 2014

    Keywords

    • Atomic force microscopy (AFM)
    • Computational fluid dynamics (CFD)
    • Hydrodynamic drag force
    • Numerical simulation

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