Dynamic Analysis of Confined Ionic Liquids and Ionic Magnetic Fluids: Highlighting Long Range Elastic Interactions

TL;DR

This paper demonstrates that ionic liquids and magnetic fluids exhibit measurable elastic properties at sub-millimeter scales due to long-range interactions, challenging the traditional view of these liquids as purely viscous.

Contribution

It extends the analysis of elastic behavior to strongly electrostatically interacting liquids, revealing mesoscopic elastic properties under external fields.

Findings

Identification of non-zero low-frequency shear elasticity in ionic and magnetic liquids

Elastic interactions contribute to collective effects under electric or magnetic fields

Elastic properties observed at sub-millimeter scales in liquids typically considered viscous

Abstract

By reinforcing the interaction energy of the liquid with respect to the surface using total wetting boundary conditions, the response of liquids to mechanical shear stress is stronger and exhibits at sub-millimeter scale elastic properties. This study extends here to liquids with strong electrostatic interactions such as ionic liquids and paramagnetic liquids. We show that it is also possible to identify and measure a non-zero low-frequency shear elasticity at sub-millimeter scale. The observation of mesoscopic elastic properties in liquids generally considered as viscous away from any phase transition and the absence of extended structuring confirm the relevance of considering elastic interactions as contributing to collective effects under external electric or magnetic field.