A QUARTZ MICROBALANCE WITH THE CAPABILITY OF VISCOELASTICITY MEASUREMENTS FOR INSITU ELECTROCHEMICAL INVESTIGATIONS

The frequency change of an electrochemical quartz crystal microbalance (EQMB) is a function of both the rigid and the viscous masses coupled to its surface. The viscoelastic properties of the contacting medium define the mechanical loss of the vibrating quartz, which is characterized by the resistance R' in the equivalent electrical circuit. In this work a new driver circuit for the EQMB is described. It permits monitoring of in situ changes of the resonant frequency f(s) and of the quartz crystal equivalent resistance R'. Thus this set-up allows one to distinguish between the rigid and viscous masses. Results obtained in different media with a prototype are discussed.