Maxwell-Wagner polarization and frequency-dependent injection at aqueous electrical interfaces. Academic Article uri icon


  • We demonstrate a new type of alternating current (ac) interfacial polarization and frequency-dependent fluid displacement phenomenon at a liquid-liquid electrical interface. Two fluid streams--one with a greater electrical conductivity and the other a greater dielectric constant--are made to flow side by side in a microfluidic channel. An ac electric field is applied perpendicular to the interface formed between the liquid lamellae, and fluid is observed to displace across the liquid-liquid interface. The direction and magnitude of this displacement is frequency dependent. At low ac frequency, below the interfacial inverse charge relaxation time, the high-conductivity fluid displaces into the high-dielectric stream. At high frequency the direction of liquid displacement reverses, and the high-dielectric stream injects into the high-conductivity stream. The interfacial crossover frequency where the liquid displacement direction reverses is dependent on differences in electrical properties between the two fluid streams, and is well explained by Maxwell-Wagner polarization mechanics.

published proceedings

  • Phys Rev Lett

author list (cited authors)

  • Desmond, M., Mavrogiannis, N., & Gagnon, Z.

citation count

  • 21

complete list of authors

  • Desmond, Mitchell||Mavrogiannis, Nicholas||Gagnon, Zachary

publication date

  • November 2012