QCM-D, Quartz Crystal Microbalance with Dissipation monitoring, is just as its name claims: a balance. It operates with an oscillating piezoelectric quartz crystal with a certain resonance frequency which changes with variations on the surface. With QCM changes in the frequency and energy dissipation is registered and can through data analysis give both a figure on the total adsorbed mass (hydration water included) and the viscoelastic property of the adsorbed layer.
The applications can be exemplified as follows:
- Adsorption and desorption, of polymers, surfactants and proteins.
- Check fouling and study cleaning processes.
- Conformational changes due to swelling and de-swelling with solvents.
- Rearrangements on the surface.
- Rheological changes such as effects of crosslinking, curing and melting of gels upon addition of agents or external stress.
- The formation of a biofilm on an implant.
It is easy to run QCM-D but very difficult to interpret the data without making large mistakes… To the left is the result of grease-removal by surfactant flowing over an oily substrate. Both removal and initial swelling of the layer can be seen.
A brief application note and a white paper, both by Tobias Halthur can be downloaded from below. You can also read about our collaboration with instrument provider Biolin.
