Direct measurement of the viscoelectric effect in water

Di Jin*, Yongyun Hwang, Liraz Chai, Nir Kampf, Jacob Klein*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The viscoelectric effect concerns the increase in viscosity of a polar liquid in an electric field due to its interaction with the dipolar molecules and was first determined for polar organic liquids more than 80 y ago. For the case of water, however, the most common polar liquid, direct measurement of the viscoelectric effect is challenging and has not to date been carried out, despite its importance in a wide range of electrokinetic and flow effects. In consequence, estimates of its magnitude for water vary by more than three orders of magnitude. Here, we measure the viscoelectric effect in water directly using a surface force balance by measuring the dynamic approach of two molecularly smooth surfaces with a controlled, uniform electric field between them across highly purified water. As the water is squeezed out of the gap between the approaching surfaces, viscous damping dominates the approach dynamics; this is modulated by the viscoelectric effect under the uniform transverse electric field across the water, enabling its magnitude to be directly determined as a function of the field. We measured a value for this magnitude, which differs by one and by two orders of magnitude, respectively, from its highest and lowest previously estimated values.

Original languageAmerican English
Article numbere2113690119
JournalProceedings of the National Academy of Sciences of the United States of America
Volume119
Issue number1
DOIs
StatePublished - 4 Jan 2022

Bibliographical note

Publisher Copyright:
© 2022 National Academy of Sciences. All rights reserved.

Keywords

  • Electrokinetic phenomena
  • Surface forces balance
  • Viscoelectric effect
  • Viscosity/electric field coupling

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