Search for: All records

Viscosity measurement has recently captured considerable attention due to its wide range of applications in fields such as pharmacy, food industry, cosmetic industry, and biomedical diagnostics. Acoustic wave sensors such as quartz crystal microbalance (QCM) are well-known mass sensors that also show their capability in measuring liquid viscosity. However, the challenges for QCM-based viscosity measurement devices lie in their low sensitivity and unstable response. Herein, we report an ultrasensitive micropillar-enabled acoustic wave (μPAW) viscometer by fabricating well-defined polymethyl methacrylate (PMMA) micropillars on a QCM substrate to achieve ultrahigh sensitivity for liquid viscosity with a stable response thanks to a unique vibration coupling between the micropillar and QCM substrate. The μPAW based viscometer shows a 20-fold improvement in the measurement sensitivity over traditional QCM viscometers and achieved an excellent limit of detection (LOD) while measuring the viscosity of sucrose liquid as low as 0.054 wt%. The microdevice developed in this work is a promising tool for the viscosity measurement of liquids.

 

Polystyrene particles simulating bacteria flow down a micro-channel in the presence of potassium chloride solution. Depending on the ionic concentration or flow rates, portion of the particles are trapped on the glass substrate due to intrinsic surface forces. A novel quartz crystal microbalance (QCM) is built into the microfluidic device to track the real-time particle deposition by shift of the resonance frequency. The new technique is promising to quantify water filtration.