Design and fabrication of a graphene-based microcantilever flow sensor for liquid flow measurement

In this paper, a piezoresistive cantilever flow sensor was fabricated to measure the velocity of water flow in the operating range of 0 to 0.7 m/s, and the influence of the operating parameters on its performance were investigated. Prior to fabrication, a computer simulation was performed to design the specification and dimension of the flowmeter and obtain the appropriate operating conditions. To fabricate a cantilever beam graphene oxide (GO), as a piezoresistive material, was coated on a polyester substrate. Then it was reduced at 130 degrees C to create semiconducting properties in the GO film. Polyvinylidene fluoride (PVDF) was dip-coated on the piezoresistive GO layer to create a waterproof and protective coating. Then, the performance of the cantilever flowmeter was determined by measuring the resistance change in different water velocities. Moreover, the bending angle of the cantilever was obtained by taking photos of the beam deflection, followed by image processing. The results revealed that the calibration curve was successfully performed by regression of output signal versus flow velocity with 2nd-order polynomial function (R-2 = 0.998). Furthermore, the overall system accuracy was reached up to +/- 3.2 % full scale. The sensitivity of the sensor in the measuring range was equal to 1.22 Omega / (m.s(-1)), and the response time of the system was measured to be less than 5 s. Ultimately, experimental data demonstrated good accordance with the simulation studies. (C) 2020 Elsevier B.V. All rights reserved.