Quartz Crystal Microbalance, QCM, and extended versions, such as Quartz Crystal Microbalance with Dissipation monitoring, QCM-D, are surface sensitive, real-time technologies that detect mass changes at the sensor surface with nanoscale resolution. Essentially, these instruments are balances for very small masses and the molecule-surface interactions are detected as changes in mass, i.e. mass uptake or mass loss, as molecules adsorb or desorb.
In addition to the changes in mass, QCM-D also captures changes in energy loss. This additional information provides insight into the viscoelastic properties of the system under study and can reveal structure as well as structural changes, such as swelling, crosslinking and collapse, of the molecular layer at the sensor surface.