Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D)

Abstract

Quartz crystal microbalance with dissipation monitoring (QCM-D) can detect changes in oscillating frequency of a quartz crystal as well as in energy dissipation of adsorption material. For example, a decreased frequency results from an increased adsorption amount, while an increased dissipation results from an increased viscoelasticity of the adsorption layer. The QCM-D can monitor the frequency and dissipation changes with less than 1 s intervals. This enables us to analyse non-equilibrium adsorption or reaction system in solution. Various sensors such as gold, silica, titania, iron oxide or polystyrene are available for the QCM-D instrument, which enables QCM-D measurement possible for a wide range of applications. Special attention should be paid to the solvation effect of the adsorption material; the amount obtained by QCM-D is expressed as “wet mass”, while that of other methods such as ellipsometry or optical reflectometry is called “dry mass”. Another important point in QCM-D measurement is the effect of viscosity and density of bulk solution because these properties also contribute to the frequency change.