A suspended polymeric microfluidic sensor for liquid flow rate measurement in microchannels

Abstract

In this study, a microfluidic cantilever flow sensor was designed and manufactured to monitor liquid flow rate within the range of 100–1000 µl/min. System simulation was also performed to determine the influential optimal parameters and compare the results with experimental data. A flowmeter was constructed as a curved cantilever with dimensions of 6.9 × 0.5 × 0.6 mm3 and a microchannel carved with a CO2 laser inside the cantilever beam. The fabrication substance was Polydimethylsiloxane. Different flow rates were injected using a syringe pump to test the performance of the flowmeter. Vertical displacement of the cantilever was measured in each flowrate using a digital microscope. According to the results, the full-scale overall device accuracy was up to ± 1.39%, and the response time of the sensor was measured to be 6.3 s. The microchip sensitivity was 0.126 µm/(µl/min) in the range of measured flow rates. The sensor could also be utilized multiple times with an acceptable error value. The experimental data obtained by the constructed microchip had a linear trend (R2 = 0.995) and were of good consistency with simulation results. Furthermore, according to the experimental and the simulation data, the initially curved cantilever structure had a higher bending and sensitivity level than a perfectly straight cantilever construction.

Ionic polymer metal composite-based microfluidic flow sensor for bio-MEMS applications

“…Values can be compared to the flow measured with standard IPMC or cantilever-based design. Mohammadamini et al, who used an optical cantilever-based flow sensor, were able to obtain a sensitivity of 0.126 µm/(µL/min) in the range of measured flow rates (0-100 µL/min) [6]. Lei et al who used a thick IPMC sensor (254µm thick) could detect flow velocity in the cm/s range in the vincinity of their IPMC sensor for flow detection in an open environment [16].…”

“…Alternatively, cantilever-based approaches have been proposed in order to precisely measure flow rate. The displacement of beams can either be recorded optically or through a piezoresistive system [6], [7]. However, the optical approach is not integrated in the microfluidics device, while the piezo material characteristics get altered overtime by temperature and liquid exposure [2].…”

Wall Shear Stress Sensors Based on Carbon Nanotube Pillars

“…2,13 They can be designed to resolve low-speed flows and can directly measure wall shear stress. 2,3,14,15 Drag-based sensors have also been designed to imitate sensory structures on bats, seals, and fish, taking the form of slender hairs extending from a surface. 16−19 However, drag-based flow sensors are intrusive measurement instruments in that the sensor is placed in the flow to be measured, which could disturb flow development.…”

“…Fluid flow sensors have been developed that operate by registering a signal based on thermal or deformation changes, − , with each category of flow sensor having advantages. By avoiding fluid heating, sensors that operate by deforming due to drag forces often boast low power requirements and better compatibility with explosive gases and sensitive biological fluids. , They can be designed to resolve low-speed flows and can directly measure wall shear stress. ,,, Drag-based sensors have also been designed to imitate sensory structures on bats, seals, and fish, taking the form of slender hairs extending from a surface. − …”