Morphology of Banded Anisotropic Structures

TL;DR

This paper investigates the formation of anisotropic banded structures in concentrated emulsions under shear flow, revealing that such patterns develop after prolonged flow evolution and are influenced by shear rates and flow history.

Contribution

It provides new insights into the time-dependent formation of anisotropic banded structures in emulsions under shear flow, highlighting the role of flow history and shear rates.

Findings

Banded structures form after prolonged flow evolution.

Pattern formation depends on shear rate and flow history.

Anisotropic structures are characterized by high and low concentration regions.

Abstract

The study of the formation of bands of drops along the direction of the vorticity in a concentrated emulsion is presented. That is, the observed anisotropic structures are characterized by regions of high concentration of drops interspaced with regions of about equal width where hardly any particles are present. These particle distributions are a clear departure to what has previously reported for this emulsion. These patterns are induced by the effect of a simple flow in circular parallel plate geometry (CSS450-Linkam), but only after a prolonged time after the inception of the flow. That is, the observation of bands in emulsions only appears after various other phenomena occur in the emulsion. That is, the separation of the flow cell plates is 100 \mu m, and the observation of bands occurs within the interval of shear rates of 3.0 to 5.0 s^{-1}, but only after a long evolution of the initial structure with a series of flows of 0.75 to 2.25 s^{-1}.