Response of a Quartz Crystal Microbalance Sensor Coated with a Viscoelastic Film in Gas Phase

摘要

This paper discusses the response of a QCM sensor which is coated with a finite viscoelastic film in gas phase applications, based on acoustic loaded impedance concept. Viscoelastic materials are often characterized by complex shear modulus. When considering viscoelastic properties of contacting film, Sauerbrey equation can not hold on its validity. Both storage modulus and loss modulus of viscoelastic film contribute to frequency shift. They will cause the extra mass effect, and make the mass of the detected viscoelastic film different from that calculated by Sauerbrey equation. The greater the viscoelastic contribution, the more the deviation. The experimental fact agrees with the theoretical model as well.