Review of the role of surfactant dynamics in drop microfluidics

Nina M Kovalchuk; Mark J H Simmons

doi:10.1016/j.cis.2023.102844

Review of the role of surfactant dynamics in drop microfluidics

Adv Colloid Interface Sci. 2023 Feb:312:102844. doi: 10.1016/j.cis.2023.102844. Epub 2023 Jan 18.

Authors

Nina M Kovalchuk¹, Mark J H Simmons²

Affiliations

¹ School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. Electronic address: n.kovalchuk@bham.ac.uk.
² School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.

PMID: 36708604
DOI: 10.1016/j.cis.2023.102844

Abstract

Surfactants are employed in microfluidic systems not just for drop stabilisation, but also to study local phenomena in industrial processes. On the scale of a single drop, these include foaming, emulsification and stability of foams and emulsions using statistically significant ensembles of bubbles or drops respectively. In addition, surfactants are often a part of a formulation in microfluidic drop reactors. In all these applications, surfactant dynamics play a crucial role and need to be accounted for. In this review, the effect of surfactant dynamics is considered on the level of standard microfluidic operations: drop formation, movement in channels and coalescence, but also on a more general level, considering the mechanisms controlling surfactant adsorption on time- and length-scales characteristic of microfluidics. Some examples of relevant calculations are provided. The advantages and challenges of the use of microfluidics to measure dynamic interfacial tension at short time-scales are discussed.

Keywords: Drop coalescence; Drop deformation; Drop formation; Microfluidic tensiometry; Microfluidics; Surfactant adsorption kinetics.

Publication types

Review