Microfluidic Exploration of the Phase Diagram of a Surfactant/Water Binary System

TL;DR

This study uses microfluidic evaporators to observe phase transitions in AOT/water solutions, enabling efficient semi-quantitative mapping of the phase diagram with minimal material and experiments.

Contribution

It demonstrates a microfluidic method for rapid, semi-quantitative exploration of surfactant/water phase behavior and kinetics.

Findings

Sequential phase transitions observed during concentration increase

Microfluidic devices enable phase diagram screening with limited samples

Kinetic behaviors of phase invasion characterized

Abstract

We investigate the behaviour of a binary surfactant solution (AOT/water) as it is progressively concentrated in microfluidic evaporators. We observe in time a succession of phase transitions from a dilute solution up to a dense state, which eventually grows and invades the microchannels. Analyzing these observations, we show that, with a few experiments and a limited amount of material, our microdevices permit a semi-quantitative screening of the equilibrium phase diagram as well as a few kinetic observations.