Tag Archive for: QCMD analysis

Publication on AWSensors technology

The Frequency‐Domain Lattice Boltzmann Method (FreqD‐LBM): A Versatile Tool to Predict the QCM Response Induced by Structured Samples

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Authors: Diethelm Johannsmann, Paul Häusner, Arne Langhoff, Christian Leppin, Ilya Reviakine, Viktor Vanoppen

Journal: Advanced Theory and Simulations

Abstract: The quartz crystal microbalance with dissipation monitoring (QCM-D) is routinely used to investigate structured samples. Here, a simulation technique is described, that predicts the shifts of frequency and half bandwidth, Δfn and ΔΓn, of a quartz resonator operating on different overtone orders, n, induced by structured samples in contact with the resonator surface in liquid. The technique, abbreviated as FreqD-LBM, solves the Stokes equation in the frequency domain. The solution provides the complex amplitude of the area-averaged tangential stress at the resonator surface, from which Δfn and ΔΓn are derived. Because the dynamical variables are complex amplitudes, the viscosity can be complex, as well. The technique naturally covers viscoelasticity. Limitations are linked to the grid resolution and to problems at large viscosity. Validation steps include viscoelastic films, rough surfaces, an oscillating cylinder in a viscous medium, and a free-floating sphere above the resonator. Application examples are soft adsorbed particles, stiff adsorbed particles, and a large, immobile spherical cap above the resonator, which allows to study the high-frequency properties of the material in the gap. FreqDLBM runs on an office PC and does not require expert knowledge of numerical techniques. It is accessible to an experimentalist.

The full article can be accessed here.

Publication on AWSensors technology

Quartz crystal microbalance with dissipation monitoring for studying soft matter at interfaces

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Authors: Diethelm Johannsmann & Ilya Reviakine

Journal: Nature Reviews Methods Primers

Abstract: Quartz crystal microbalance with dissipation monitoring (QCM-D) probes interfaces by subjecting them to a periodic shear stress exerted by an acoustic resonator. The changes in the resonance frequency, Δf, and the half-width at half-maximum of the resonance, ΔΓ (closely related to the changes in the dissipation, ΔD), measured with the QCM-D are proportional to the in-phase and out-of-phase components of the area-averaged transverse stress at the resonator surface, respectively. Amounts, organization and properties of soft matter at an interface between the resonator and a liquid or a gas are derived from the measurements of Δf and ΔΓ on multiple overtones at megahertz frequencies. The properties include viscoelasticity and stress relaxation dynamics on the timescale of the oscillation period. This Primer offers guidelines on instrument design, experimental procedures and data analysis for interpreting frequency and bandwidth changes in terms of structure and dynamics of the sample. There is a focus on recent progress in the analysis of the acoustic ratio, ΔΓ/(−Δf), and numerical methods of modelling. Limitations of the existing approaches for data analysis are discussed. Challenges and possible future developments are formulated in an outlook.

The full article can be accessed here.

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IVACE nos concede la ayuda INNOVATeiC-CV 2021 para innovación en TEICs

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Advanced Wave Sensors S.L. (AWSensors) ha sido seleccionada como beneficiaria de una ayuda concedida por el Instituto Valenciano de Competitividad Empresarial (IVACE) para llevar a cabo el proyecto “Desarrollo de un software de análisis y extracción de parámetros para sensores QCM-D (AWS-DM)” en el marco del programa INNOVATeiC-CV 2021. Este proyecto ha sido cofinanciado por IVACE y el Fondo Europeo de Desarrollo Regional (FEDER) dentro del Programa Operativo FEDER de la Comunitat Valenciana 2021-2027.

El objetivo principal del proyecto es el desarrollo de un nuevo software de análisis que permita interpretar y extraer parámetros físicos de interés de la muestra a partir de la monitorización de la frecuencia de resonancia y del factor de calidad de los diferentes modos de vibración propios de los resonadores acústicos.

Esta aplicación transformará los parámetros característicos de los sensores de onda acústica en propiedades de la muestra relevantes para el usuario de la tecnología: espesor, densidad, viscoelasticidad, porosidad, rugosidad o afinidad analítica entre otras. Para ello, aplicará modelos físicos complejos descritos en la literatura científica para caracterizar los diferentes fenómenos que se dan en los sensores acústicos durante las interacciones moleculares. La aplicación software resolverá dichos modelos empleando un conjunto de algoritmos de procesado y métodos de ajuste no lineal específicamente desarrollados.

Las principales innovaciones que presenta este software son: un “core” de cálculo eficiente específicamente desarrollado para resolver los modelos matemáticos de referencia, una amplia librería de modelos validados descritos en la literatura científica asociada, un módulo estadístico que evaluará la bondad del análisis, capacidad para realizar análisis comparativo de experimentos, un interfaz de usuario muy intuitivo que servirá de guía en el complejo proceso de interpretación de resultados y un potente módulo de representación gráfica.

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