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.