A Numerical Study on the Effect of Particle Surface Coverage on the Quartz Crystal Microbalance Response

Area of Science:

• Surface Science
• Materials Characterization
• Nanotechnology

Background:

• Quartz crystal microbalance (QCM) is a sensitive technique for studying adsorption at solid-fluid interfaces.
• Characterizing heterogeneous films with QCM is challenging due to coupled fluid dynamics.
• Existing QCM models are limited to very low or saturated surface coverages.

Purpose of the Study:

• Investigate QCM responses in intermediate surface coverage regimes.
• Develop a model to extract particle information from QCM data.
• Provide a theoretical basis for particle size determination using QCM.

Main Methods:

• Conducted lattice Boltzmann simulations of monodisperse spherical particles on an oscillating surface.
• Related QCM frequency and bandwidth shifts to particle characteristics.
• Validated simulation results against experimental QCM data for liposomes.

Main Results:

• Established relationships between overtone-dependent QCM shifts and particle size, interparticle distance, and hydrodynamic length.
• Simulation results showed qualitative agreement with experimental QCM data for sub-100 nm liposomes.
• Developed a method to extract particle sizes from QCM data in high surface coverage scenarios.

Conclusions:

• QCM analysis can be extended to heterogeneous films in intermediate coverage regimes.
• Lattice Boltzmann simulations provide a robust framework for interpreting complex QCM data.
• This work offers a theoretical foundation for precise particle characterization using QCM.