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Insulator-based dielectrophoretic focusing and trapping of particles in non-Newtonian fluids |
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| Authors: | Joseph Bentor Amirreza Malekanfard Mahmud Kamal Raihan Sen Wu Xinxiang Pan Yongxin Song Xiangchun Xuan |
| Institution: | 1. Department of Mechanical Engineering, Clemson University, Clemson, SC, USA;2. Department of Mechanical Engineering, Clemson University, Clemson, SC, USA
College of Marine Engineering, Dalian Maritime University, Dalian, P. R. China;3. College of Marine Engineering, Dalian Maritime University, Dalian, P. R. China College of Electronics and Information Engineering, Guangdong Ocean University, Zhanjiang, P. R. China;4. College of Marine Engineering, Dalian Maritime University, Dalian, P. R. China |
| Abstract: | Insulator-based dielectrophoretic (iDEP) microdevices have been limited to work with Newtonian fluids. We report an experimental study of the fluid rheological effects on iDEP focusing and trapping of polystyrene particles in polyethylene oxide, xanthan gum, and polyacrylamide solutions through a constricted microchannel. Particle focusing and trapping in the mildly viscoelastic polyethylene oxide solution are slightly weaker than in the Newtonian buffer. They are, however, significantly improved in the strongly viscoelastic and shear thinning polyacrylamide solution. These observed particle focusing behaviors exhibit a similar trend with respect to electric field, consistent with a revised theoretical analysis for iDEP focusing in non-Newtonian fluids. No apparent focusing of particles is achieved in the xanthan gum solution, though the iDEP trapping can take place under a much larger electric field than the other fluids. This is attributed to the strong shear thinning-induced influences on both the electroosmotic flow and electrokinetic/dielectrophoretic motions. |
| Keywords: | Dielectrophoresis Electrokinetic Microfluidics Particle manipulation Shear thinning Viscoelasticity |