Tunable Aqueous Virtual Micropore

Authors

  • Jae Hyun Park,

    1. Physics Division, Oak Ridge National Laboratory, PO Box 2008, Bldg. 6010, Oak Ridge, TN 37831, USA, Phone: +1-865-574-4701; Fax: +1-865-574-1118
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  • Weihua Guan,

    1. Department of Electrical Engineering, Yale University, New Haven, CT 06520, USA
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  • Mark A. Reed,

    1. Department of Electrical Engineering, Yale University, New Haven, CT 06520, USA
    2. Department of Applied Physics, Yale University, New Haven, CT 06520, USA
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  • Predrag S. Krstić

    Corresponding author
    1. Physics Division, Oak Ridge National Laboratory, PO Box 2008, Bldg. 6010, Oak Ridge, TN 37831, USA, Phone: +1-865-574-4701; Fax: +1-865-574-1118
    • Physics Division, Oak Ridge National Laboratory, PO Box 2008, Bldg. 6010, Oak Ridge, TN 37831, USA, Phone: +1-865-574-4701; Fax: +1-865-574-1118.
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Abstract

A charged microparticle can be trapped in an aqueous environment by forming a narrow virtual pore—a cylindrical space region in which the particle motion in the radial direction is limited by forces emerging from dynamical interactions of the particle charge and dipole moment with an external radiofrequency quadrupole electric field. If the particle satisfies the trap stability criteria, its mean motion is reduced exponentially with time due to the viscosity of the aqueous environment; thereafter the long-time motion of particle is subject only to random, Brownian fluctuations, whose magnitude, influenced by the electrophoretic and dielectrophoretic effects and added to the particle size, determines the radius of the virtual pore, which is demonstrated by comparison of computer simulations and experiment. The measured size of the virtual nanopore could be utilized to estimate the charge of a trapped micro-object.

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