Mechanical characterization of ultralow interfacial tension oil-in-water droplets by thermal capillary wave analysis in a micro uidic device

Abstract

Measurements of the ultralow interfacial tension and surfactant film bending rigidity for micron-sized heptane droplets in bis(2-ethylhexyl) sodium sulfosuccinate−NaCl aqueous solutions were performed in a microfluidic device through the analysis of thermally driven droplet interface fluctuations. The Fourier spectrum of the stochastic droplet interface displacement was measured through bright-field video microscopy and a contour analysis technique. The droplet interfacial tension, together with the surfactant film bending rigidity, was obtained by fitting the experimental results to the prediction of a capillary wave model. Compared to existing methods for ultralow interfacial tension measurements, this contactless, nondestructive, all-optical approach has several advantages, such as fast measurement, easy implementation, cost-effectiveness, reduced amount of liquids, and integration into lab-on-a-chip devices.

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Cite this paper

@inproceedings{Bolognesi2017MechanicalCO, title={Mechanical characterization of ultralow interfacial tension oil-in-water droplets by thermal capillary wave analysis in a micro uidic device}, author={Guido Bolognesi and Yuki Saito and Arwen I I Tyler and Andrew D. Ward and C. D. Bain and Oscar Ces}, year={2017} }