Using the Quartz Crystal Microbalance with Dissipation Monitoring to Evaluate the Size of Nanoparticles Deposited on Surfaces

A quartz crystal microbalance with dissipation (QCM-D) monitoring can be an alternative tool to characterize nanoparticle size by virtue of its acoustic principle to sense adsorbed mass. In this study, sizes obtained by QCM-D for polymer-coated metallic nanoparticles and polydisperse polystyrene latex particle suspensions were compared with those obtained by transmission electron microscopy (TEM) and dynamic light scattering (DLS). We describe the obtained "QCM-D mass", which is weighted over surface area, by a general particle height distribution equation that can be used to determine the average particle diameter of a distribution of particles deposited on the QCM-D surface. Because the particle height distribution equation can be used for any particle geometry and surface packing geometry, it is described how the QCM-D can also be used to study the orientation of deposited nonspherical particles. Herein, the mean nanoparticle sizes obtained by QCM-D were generally in closer agreement with the primary particle size determined by TEM than with the sizes obtained by DLS, suggesting that primarily smaller particles within the particle population deposited on the sensor surface. Overall, the results from this study demonstrate that QCM-D could serve as an alternative and/or complementary means to characterize the size of nanoparticles deposited on a surface from suspensions of varying complexity.