Viscosimetry using a new electromagnetic-acoustic microbalance

• Published in: The Journal of the Acoustical Society of America 2008-05, Vol.123 (5_Supplement), p.3836-3836
• Main Authors: Caplain, Emmanuel, Serfaty, Stéphane, Griesmar, Pascal, Le Huerou, Jean-Yves, Wilkie-Chancellier, Nicolas
• Format: Article
• Language: English
• Subjects: Acoustics; Electronics; Engineering Sciences; Signal and Image processing
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.2935629

The nanostructure evolution of gels, biomaterials or porous media can be characterized by its mechanical properties. Few nondestructive techniques are developed to investigate the viscosity evolution. This paper present a new electromagnetic-acoustic technique using a wireless thickness shear mode transducer. A suitable model of the measurement is also presented to characterize the viscosity of the nanostructure in contact with the transducer. This transducer is a double copper-clad PVDF substrate resonator, designed to operate over a wide radiofrequency range without lumped tuning capacitors. This architecture constitutes an alternative solution to design a high-Q ultrasonic microbalance. To characterize the material at the surface of the transducer, the evolution of the induced complex impedance is measured. From this evolution, the mechanical energy storage and dissipation in the material can be extracted. In order to validate the lumped element model used, a series of glycerol/water mixtures is studied. We show that the resonant frequency shift and damping follow an accurate linear shape (