title: Electrothermal flow on electrodes arrays at physiological conductivities.
abstract: AC electrothermal (ET) flow is inevitable for microfluidic systems dissipating electric energy in a conducting medium. Therefore, many practical applications of biomicrofluidics are prone to ET flow. Here, a series of observations are reported on ET flow in a microfluidic chamber that houses three electrode pairs. The observations indicate that the variations in liquid conductivity and channel height critically impact the structure and magnitude of the flow field. Observations indicate that after a critical conductivity a global ET flow is present in the chamber, while at lower conductivities a vortex is present at every electrode edge. In addition, no ET flow is observed when the chamber height is kept below a critical value at physiological conductivity (∼1.5 S/m). The experimental observations are compared with the numerical simulations of ET flow. The validity of the assumptions made in the current AC ET flow theory is also discussed in the light of the experimental data. The observations can be critical while designing microfluidic systems that involve power dissipation in conductive fluids.
authors.affiliation: Department of Mechanical Engineering, Istanbul Technical University, Istanbul 34437, Turkey.
authors.forename: Anil
authors.initials: A
authors.lastname: Koklu
authors.affiliation: Department of Mechanical Engineering, Istanbul Technical University, Istanbul 34437, Turkey.
authors.forename: Osman
authors.initials: O
authors.lastname: Tansel
authors.affiliation: Department of Mechanical Engineering, Istanbul Technical University, Istanbul 34437, Turkey.
authors.forename: Hakan
authors.initials: H
authors.lastname: Oksuzoglu
authors.affiliation: Department of Mechanical Engineering, Istanbul Technical University, Istanbul 34437, Turkey. asabuncu@smu.edu.
authors.forename: Ahmet C
authors.initials: AC
authors.lastname: Sabuncu
mesh_terms: D004553:Electric Conductivity; D004563:Electrochemistry; D004566:Electrodes; D005456:Fluorescent Dyes / Q000737:chemistry / Q000493:pharmacokinetics; D056656:Lab-On-A-Chip Devices; D044085:Microfluidics / Q000295:instrumentation*; D009038:Motion; D053758:Nanoparticles / Q000737:chemistry; D012212:Rheology
chemical_list: D005456:Fluorescent Dyes