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Laboratoire Ondes et Matière d'Aquitaine |  |
Contactless Rheology of Soft Gels over a Broad Frequency Range
Abstract : We report contactless measurements of the viscoelastic rheological properties of soft gels. The experiments are performed using a colloidal-probe Atomic Force Microscope (AFM) in a liquid environment and in dynamic mode. The mechanical response is measured as a function of the liquid gap thickness for different oscillation frequencies. Our measurements reveal an elastohydrodynamic (EHD) coupling between the flow induced by the probe oscillation and the viscoelastic deformation of the gels. The data are quantitatively described by a viscoelastic lubrication model. The frequency-dependent storage and loss moduli of the polydimethylsiloxane (PDMS) gels are extracted from fits of the data to the model and are in good agreement with the Chasset–Thirion law. Our results demonstrate that contactless colloidal-probe methods are powerful tools that can be used for probing soft interfaces finely over a wide range of frequencies.
https://hal.archives-ouvertes.fr/hal-03562373
Contributor : Thomas Salez Connect in order to contact the contributor
Submitted on : Tuesday, February 8, 2022 - 8:35:17 PM
Last modification on : Thursday, February 10, 2022 - 3:35:31 AM
Contributor : Thomas Salez Connect in order to contact the contributor
Submitted on : Tuesday, February 8, 2022 - 8:35:17 PM
Last modification on : Thursday, February 10, 2022 - 3:35:31 AM