Transition phenomenon of immersion-angle dependence of quartz crystal microbalance in Newtonian liquid

The present work reports the new effects of the immersion-angle dependence of the resonant-frequency shift (ΔF) of the one-face sealed quartz crystal microbalance (QCM) in a Newtonian liquid. The immersion-angle dependence of ΔF appears below the sucrose concentration of 12 wt.%. However, we found that the transition phenomenon of ΔF occurs between 12 and 20 wt.% and then the immersion-angle dependence of ΔF disappears above 20 wt.% (finally, the ΔF values above 20 wt.% are equal to those of 90° in all immersion angles). In order to obtain further insights into the transition phenomenon and the disappearance of the immersion-angle dependence of ΔF, we investigated the immersion-angle dependence of the electrolytic solution, i.e., NaCl solution. This investigation indicated that this monovalent electrolytic solution causes the immersion-angle dependence but not the transition phenomenon and the disappearance of the immersion-angle dependence of ΔF. On the basis of these results, we suggest that the non-charge of the molecule is the important element to generate the transition phenomenon and the disappearance of the immersion-angle dependence of ΔF.