Temperature-gradient induced massive augmentation of solute dispersion in viscoelastic micro-flows

TL;DR

This paper demonstrates that applying a temperature gradient in viscoelastic micro-flows significantly enhances solute dispersion, leveraging thermal, electrical, and rheological interactions for improved microfluidic device performance.

Contribution

It reveals a novel mechanism where temperature gradients coupled with electro-rheological effects substantially boost solute dispersion in microflows.

Findings

Achieved up to tenfold increase in solute dispersion.

Identified the interplay of thermal, electrical, and rheological effects as key.

Potential applications in microfluidic device design.

Abstract

Enhancing solute dispersion in electrically actuated flows has always been a challenging proposition, as attributed to the inherent uniformity of the flow field in absence of surface patterns. Over the years, researchers have focused their attention towards circumventing this limitation, by employing several fluidic and geometric modulations. However, the corresponding improvements in solute dispersion often turn out to be inconsequential. Here we unveil that by exploiting the interplay between an externally imposed temperature gradient, subsequent electrical charge redistribution and ionic motion, coupled with the rheological complexities of the fluid, one can achieve up to one order of magnitude enhancement of solute dispersion in a pressure-driven flow of an electrolyte solution. Our results demonstrate that the complex coupling between thermal, electrical, hydro-dynamic and rheological parameters over small scales, responsible for such exclusive phenomenon, can be utilitarian in designing novel thermally-actuated micro and bio-microfluidic devices with favorable solute separation and dispersion characteristics.