title: An unexpected particle oscillation for electrophoresis in viscoelastic fluids through a microchannel constriction.
abstract: Electrophoresis plays an important role in many applications, which, however, has so far been extensively studied in Newtonian fluids only. This work presents the first experimental investigation of particle electrophoresis in viscoelastic polyethylene oxide (PEO) solutions through a microchannel constriction under pure DC electric fields. An oscillatory particle motion is observed in the constriction region, which is distinctly different from the particle behavior in a polymer-free Newtonian fluid. This stream-wise particle oscillation continues until a sufficient number of particles form a chain to pass through the constriction completely. It is speculated that such an unexpected particle oscillating phenomenon is a consequence of the competition between electrokinetic force and viscoelastic force induced in the constriction. The electric field magnitude, particle size, and PEO concentration are all found to positively affect this viscoelasticity-related particle oscillation due to their respective influences on the two forces.
authors.affiliation: Department of Mechanical Engineering, Clemson University, Clemson, South Carolina 29634-0921, USA.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Lu
authors.affiliation: Department of Mechanical Engineering, Clemson University, Clemson, South Carolina 29634-0921, USA.
authors.forename: Saurin
authors.initials: S
authors.lastname: Patel
authors.affiliation: Department of Chemical and Biomolecular Engineering, and Center for Advanced Engineering Fibers and Films, Clemson University, Clemson, South Carolina 29634-0909, USA.
authors.forename: Meng
authors.initials: M
authors.lastname: Zhang
authors.affiliation: School of Mechanical Engineering, Yeungnam University, Gyongsan 712-719, South Korea.
authors.forename: Sang
authors.initials: S
authors.lastname: Woo Joo
authors.affiliation: Institute of Micro/Nanotechnology, Old Dominion University, Norfolk, Virginia 23529, USA.
authors.forename: Shizhi
authors.initials: S
authors.lastname: Qian
authors.affiliation: Department of Chemical and Biomolecular Engineering, and Center for Advanced Engineering Fibers and Films, Clemson University, Clemson, South Carolina 29634-0909, USA.
authors.forename: Amod
authors.initials: A
authors.lastname: Ogale
authors.affiliation: Department of Mechanical Engineering, Clemson University, Clemson, South Carolina 29634-0921, USA.
authors.forename: Xiangchun
authors.initials: X
authors.lastname: Xuan