Measurement of mixing ratio and volume change of ethanol-water binary mixtures using suspended microchannel resonators

We report, for the first time, temperature-dependent characteristics of suspended microchannel resonators (SMRs) and apply them to measure ethanol-water binary mixtures. First, the resonance frequency of the SMR is measured with ethanol-water binary mixtures at different temperatures. When the ethanol mole fraction is sufficiently low, the resonance frequency vs. temperature plot exhibits a local minimum thus shows a non-monotonic trend. The temperature at the frequency minimum depends on the ethanol mole fraction. Second, density calibration is done within a range of temperature. The sensitivity in density measurements increases with temperature. Aforementioned results are due to the interplay between the elastic modulus of the structural material and the mass density of mixtures both of which are temperature dependent. Using such characteristics of the SMR, density and volume contraction of ethanol-water binary mixtures are measured precisely. Based on our experiments, we find out that the temperature effect on the volume contraction also depends on the ethanol mole fraction.