This is an application which enables calculation of viscoelastic properties from quartz crystal microbalance (QCM-D) data by fitting ΔF and ΔD QCM response to the Kelvin-Voigt viscoelastic model to obtain viscosity and shear modulus of an adlayer film, enabling estimation of G' and G'' (elastic and loss moduli).
Use the User Inputs section to input experimental data. Run the viscoelastic model. Solutions for the ΔF response are shown as contours on the ΔF plot. Solutions for ΔD are shown as contours on the ΔD plot, and solutions of the complete model are found where the two ΔF and ΔD solutions intersect (last plot). Once the solution is found, you may adjust the range of μ and η values to limit the search space and obtain a solution with higher precision. Hover the mouse over the Hover for help button to see more help.
To use the application, download this repositoary as a zip file, and extract it on the local PC. Then open Python and run app.py in the QCMD_calculator folder. Dependencies such as PyQt may need to be installed using Anaconda or pip. All dependencies are listed below. To edit the user interface, use QtDesigner (it comes prepackaged with Anaconda) and open the ui.ui file to edit.
- PyQt5
- numpy
- pandas
- matplotlib
- shapley
For more information about the viscoelastic model, see:
- Voinova, M.V., Rodahl, M., Jonson, M. and Kasemo, B., 1999. Viscoelastic acoustic response of layered polymer films at fluid-solid interfaces: continuum mechanics approach. Physica Scripta, 59(5), p.391. https://iopscience.iop.org/article/10.1238/Physica.Regular.059a00391/meta
- Liu, S.X. and Kim, J.T., 2009. Application of Kelvin—Voigt model in quantifying whey protein adsorption on polyethersulfone using QCM-D. JALA: Journal of the Association for Laboratory Automation, 14(4), pp.213-220. https://journals.sagepub.com/doi/full/10.1016/j.jala.2009.01.003