In Situ Interfacial Mass Detection with Piezoelectric Transducers

Abstract

The converse piezoelectric effect, in which an electric field applied across a piezoelectric material induces a stress in that material, has spurred many recent developments in mass measurement techniques. These methods commonly rely on the changes in the vibrational resonant frequency of piezoelectric quartz oscillators that result from changes in mass on the surface of the oscillator. The dependence of frequency on mass has been exploited extensively for mass measurements in vacuum or gas phase, for example, thickness monitors for thin-film preparation and sensors for chemical agents. Advances in piezoelectric methodology in the last decade now allow dynamic measurements of minute mass changes (< 10(-9) grams per square centimeter) at surfaces, thin films, and electrode interfaces in liquid media as well. Mass measurements associated with a diverse collection of interfacial processes can be readily performed, including chemical and biological sensors, reactions catalyzed by enzymes immobilized on surfaces, electron transfer at and ion exchange in thin polymer films, and doping reactions of conducting polymers.

Thermophysical Properties of Penetrants in Polymers via a Piezoelectric Quartz Crystal Microbalance

“…The Curies experimentally verified the converse piezoelectric effect, in which application of a voltage across the piezoelectric crystals induces a mechanical strain (Ward and Buttry, 1990).…”

“…The application of an alternating electric field across a quartz crystal substrate resulted in an alternating strain field. The alternating strain field caused oscillatory motion in the quartz crystal (Ward and Buttry, 1990 (Bottom, 1982).…”

“…The piezoelectric effect was first discovered by Pierre and Jacques Curie in 1880 (Ward and Buttry, 1990). Ever since, quartz crystals have been used extensively as electromechanical transducers and as highly stable oscillators for frequency control.…”

Weighing graphene with QCM to monitor interfacial mass changes

“…This configuration yields large quality factors of 10 000-100 000. 12,13 Owing to low cost and conceptual simplicity, quartz crystal microbalance provides sensitive means of in situ determination of interfacial mass change. 14 QCM consists of a thin piezoelectric quartz crystal sandwiched between two metal electrodes.…”

“…The quality factor of a QCM can exceed 100 000 making QCM an ideal oscillator for sensing extremely small mass variations. 13 We integrated QCM with graphene using a transferprinting process (Fig. 1).…”