title: Non-vanishing ponderomotive AC electrophoretic effect for particle trapping.
abstract: We present here a study on overlooked aspects of alternating current (AC) electrokinetics-AC electrophoretic (ACEP) phenomena. The dynamics of a particle with both polarizability and net charges in a non-uniform AC electric trapping field is investigated. It is found that either electrophoretic (EP) or dielectrophoretic (DEP) effects can dominate the trapping dynamics, depending on experimental conditions. A dimensionless parameter γ is developed to predict the relative strength of EP and DEP effects in a quadrupole AC field. An ACEP trap is feasible for charged particles in 'salt-free' or low salt concentration solutions. In contrast to DEP traps, an ACEP trap favors the downscaling of the particle size.
authors.affiliation: Department of Electrical Engineering, Yale University, New Haven, CT 06520, USA.
authors.forename: Weihua
authors.initials: W
authors.lastname: Guan
authors.forename: Jae Hyun
authors.initials: JH
authors.lastname: Park
authors.forename: Predrag S
authors.initials: PS
authors.lastname: Krstić
authors.forename: Mark A
authors.initials: MA
authors.lastname: Reed