Quality Factor of a Microchannel Microresonator as a Function of Viscosity and Its Vibrational Mode: An Experimental and Computational Analysis

Fluid density and viscosity need to be determined in numerous industrial applications. Thus, new methods are required that measure fluid properties with minimum interference of extraneous factors. Herein, 150 pL of different chemicals, namely, ethanol, 1-butanol, ethylene glycol,
${n}$
-hexadecane, and water, were injected into an enclosed microfluidic channel on top of a microcantilever resonator sensor. Then, resonance frequencies of four vibrational modes and quality factors (
${Q}$
-factors) were experimentally measured as functions of fluid density and viscosity. The four resonant frequencies
${f}1$
–
${f}4$
consistently increased as the fluid mass decreased. The
${Q}$
-factor for the first mode decreased with increasing viscosity; however, it increased for higher modes. Numerical modal analysis results were compared to the experimental results. The obtained experimental and numerical resonance frequencies are in good agreement, where the numerical values agree well with the experimental results obtained for the first three modes, with only an 8% ± 2% difference.