title: Real-time measurement of flow rate in microfluidic devices using a cantilever-based optofluidic sensor.
abstract: Real-time and accurate measurement of flow rate is an important reqirement in lab on a chip (LOC) and micro total analysis system (μTAS) applications. In this paper, we present an experimental and numerical investigation of a cantilever-based optofluidic flow sensor for this purpose. Two sensors with thin and thick cantilevers were fabricated by engraving a 2D pattern of cantilever/base on two polymethylmethacrylate (PMMA) slabs using a CO2 laser system and then casting a 2D pattern with polydimethylsiloxane (PDMS). The basic working principle of the sensor is the fringe shift of the Fabry-Pérot (FP) spectrum due to a changing flow rate. A Finite Element Method (FEM) is used to solve the three dimensional (3D) Navier-Stokes and structural deformation equations to simulate the pressure distribution, velocity and cantilever deflection results of the flow in the channel. The experimental results show that the thin and thick cantilevers have a minimum detectable flow change of 1.3 and 4 (μL min(-1)) respectively. In addition, a comparison of the numerical and experimental deflection of the cantilever has been done to obtain the effective Young's modulus of the thin and thick PDMS cantilevers.
authors.affiliation: Laser & Plasma Research Institute, Shahid Beheshti University, Evin, Tehran 1983963113, Iran. latifi@sbu.ac.ir.
authors.forename: Mohammad Sadegh
authors.initials: MS
authors.lastname: Cheri
authors.forename: Hamid
authors.initials: H
authors.lastname: Latifi
authors.forename: Jalal
authors.initials: J
authors.lastname: Sadeghi
authors.forename: Mohammadreza Salehi
authors.initials: MS
authors.lastname: Moghaddam
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Shahraki
authors.forename: Hasan
authors.initials: H
authors.lastname: Hajghassem
mesh_terms: D055119:Elastic Modulus; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D055620:Optical Phenomena; D013997:Time Factors