Inducing AC-electroosmotic flow using electric field manipulation with insulators. Issue 16 (13th July 2021)

• Record Type: Journal Article
• Authors: Tiflidis, C.; Westerbeek, Eiko Y.; Jorissen, Koen F. A.; Olthuis, Wouter; Eijkel, Jan C. T.; De Malsche, Wim
• Is Part Of: Lab on a chip. Volume 21:Issue 16(2021)
• Page Start: 3105
• Page End: 3111
• Publication Date: 2021-07-13
• Subjects: Miniature electronic equipment -- Periodicals; Combinatorial chemistry -- Periodicals; Biotechnology -- Periodicals; 543.0813
• DOI: 10.1039/d1lc00393c
• Languages: English
• ISSNs: 1473-0197

Abstract

Abstract : We demonstrate a new method to induce vortices with AC-EOF by shaping insulator materials near parallel electrodes, giving control of vortex organization. Interestingly, non-orthogonality of insulator walls is a requirement to induce AC-EOF. Abstract : Classically, the configuration of electrodes (conductors) is used as a means to determine AC-electroosmotic flow patterns. In this paper, we use the configuration of insulator materials to achieve AC-electroosmotic flow patterning in a novel approach. We apply AC electric fields between parallel electrodes situated on the top and bottom of a microfluidic channel and separated by an insulating material. Channels of various cross-sectional shapes ( e.g. rectangular and parallelogram) were fabricated by shaping the insulating material between the electrodes. We found that vortex flow patterns are induced depending on the cross-sectional shape of the channel. A bell-shaped design with non-orthogonal corners gave rise to 2 vortices, whereas in a channel with a parallelogram shaped cross-section, only a single vortex was observed. The vortices were experimentally observed by analysing the 3D trajectories of fluorescent microparticles. From a theoretical analysis, we conclude that flow shaping is primarily caused by shaping the electrical field lines in the channel.