Acoustic control of evaporative colloidal self-assembly: suppression of the coffee-ring effect

Mampallil, D., Reboud, J. , Wilson, R. , Wylie, D., Klug, D. R. and Cooper, J. M. (2015) Acoustic control of evaporative colloidal self-assembly: suppression of the coffee-ring effect. Soft Matter, 11(36), pp. 7207-7213. (doi: 10.1039/c5sm01196e)

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We study the influence of acoustic fields on the evaporative self-assembly of solute particles suspended inside sessile droplets of complex fluids. The self-assembly process often results in an undesirable ring-like heterogeneous residue, a phenomenon known as the coffee-ring effect. Here we show that this ring-like self-assembly can be controlled acoustically to form homogeneous disc-like or concentrated spot-like residues. The principle of our method lies in the formation of dynamic patterns of particles in acoustically excited droplets, which inhibits the evaporation-driven convective transport of particles towards the contact line. We elucidate the mechanisms of this pattern formation and also obtain conditions for the suppression of the coffee-ring effect. Our results provide a more general solution to suppress the coffee-ring effect without any physiochemical modification of the fluids, the particles or the surface, thus potentially useful in a broad range of industrial and analytical applications that require homogenous solute depositions.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Mampallil Augustine, Dr Dileep and Wilson, Dr Robert and Cooper, Professor Jonathan and Reboud, Professor Julien
Authors: Mampallil, D., Reboud, J., Wilson, R., Wylie, D., Klug, D. R., and Cooper, J. M.
College/School:College of Science and Engineering > School of Engineering > Biomedical Engineering
Journal Name:Soft Matter
Publisher:Royal Society of Chemistry
ISSN (Online):1744-6848
Copyright Holders:Copyright © 2015 The Authors
First Published:First published in Soft Matter 11(36):7207-7213
Publisher Policy:Reproduced under a Creative Commons License
Data DOI:10.5525/gla.researchdata.198

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
617021Advanced Diagnostics using PhononicsJonathan CooperEngineering & Physical Sciences Research Council (EPSRC)EP/K027611/1ENG - BIOMEDICAL ENGINEERING