Viscoelastic, mechanical, and dielectric measurements on complex samples with the quartz crystal microbalance.
Piezoelectric resonators have been in use as mass-sensing devices for almost half a century. More recently it was recognized that shifts in frequency and bandwidth can come about by a diverse variety of interactions with the sample. The classical "load" consists of a thin film, which shifts the resonance frequency due to its inertia. Other types of loading include semi-infinite viscoelastic media, rough objects contacting the crystal via isolated asperities, mechanically nonlinear contacts, and dielectric films. All these interactions can be analyzed within the small-load approximation. The small-load approximation provides a unified frame for interpretation and thereby opens the way to new applications of the QCM.
Johannsmann
Diethelm
D
Institute of Physical Chemistry, Clausthal University of Technology, Arnold-Sommerfeld-Strasse 4, Clausthal-Zellerfeld, Germany. johannsmann@pc.tu-clausthal.de