Characteristics of the series resonant-frequency shift of a quartz crystal microbalance in electrolyte solutions

Abstract

We report the novel characteristics of the series resonant-frequency shift, ΔF, of a one-face sealed quartz crystal microbalance (QCM) in solutions of monovalent electrolytes and divalent electrolytes. In the present study, we used NaCl, KCl, LiCl, NaNO₃ and CH₃COONa as monovalent electrolytes, and MgCl₂, CaCl₂, MgSO₄ and Na₂SO₄ as divalent electrolytes. These experiments reveal that, in all the solutions, the ΔF values vary linearly with an increase in the square root of the density–viscosity product of the solutions, and the immersion angle dependence of ΔF appears. Moreover, we have found that the intercept values of ΔF are dependent only on the cation species, and that the slope values of ΔF with the viscosity and density of the solutions are related only to the valence of ions. We also suggest that the ΔF values are independent of anion species, conductivity and permittivity of the solutions.