Measurement of Mass and Surface Stress at One Electrode of a Quartz Oscillator

Abstract

The theory for the calculation of changes of mass and surface stress from frequency measurements at a quartz oscillator subject to different onesided pressures is outlined. The various contributions to apparent changes of the mass are discussed. Experiments refer to the determination of effective molar masses of potassium ions and fluoride ions during electrostatic adsorption and of chemisorbed lead both on polycrystalline gold by a comparison of masses to charges. Effective molar masses of adsorbed species can also be determined by comparison of mass changes to surface concentrations e.g. determined by the radiotracer method as in the example of the adsorption of chloride at the passivating oxide film on iron. The density of very thin films like the passivating oxide film can be obtained by comparing mass changes to thicknesses from optical measurements. In agreement with theoretical expectation, compressive surface stresses were qualitatively found for the underpotential deposition of lead on gold. In the growing oxide film on passive iron very large compressive lateral pressures were observed.

EQCM studies on oxidation of metallic nickel electrode in basic solutions

“…0.2 mm, f 0 is a resonant frequency, here 4.999 MHz, and dS s is a change in the plane of the film due to stress generation. The latter parameter is equal to force per unit width acting parallel to Ni/Ni(II) compound interface with sign different for compressive and tensile stress: for compressive stress in the film deposited on the quartz crystal obtained df s has a negative value [76,74,75]. This indicates that in our case stress causes greater decrease in the frequency than under stress free conditions.…”

“…Although we did not perform these measurements we can make an attempt to estimate the frequency shift due to the stress generation. Heusler et al [75] described parabolic relation between the frequency shift and the surface stress. The coefficient in the equation describing mentioned relation must be measured experimentally since the method of its theoretical calculation was not presented.…”

Grundsätzliche Probleme der Korrosion von Legierungen

“…Mit der plastischen Verformung erho Èhen sich die Dichte an der Oberfla Èche endender Versetzungen und so die Wahrscheinlichkeiten fu Èr Keimbildung und Wachs-tum von Stufen. Groûe Verspannungen wurden wa Èhrend der Passivierung und Aktivierung von Eisen gefunden [51,52]. Es wurde jedoch nicht untersucht, ob die Verspannungen das Metall plastisch verformen.…”

Monitoring of integrin-mediated adhesion of human ovarian cancer cells to model protein surfaces by quartz crystal resonators: evaluation in the impedance analysis mode

“…It is routinely used for determination of film thickness (Sauerbrey, 1964). Other parameters like pressure (Besson et al, 1993), temperature (Simon, 1997), surface stress (Heusler et al, 1988), and viscosity (Kanazawa and Gordon, 1985) can also be inferred from the frequency shifts of quartz resonators. Currently, much effort is spent to explore the application of the QCM technique to investigate adsorption phenomena occurring in biological processes, e.g.…”