Microfluidic ultralow interfacial tensiometry with magnetic particles

作者：Tsai Scott S H; Wexler Jason S; Wan Jiandi; Stone Howard A^*

来源：Lab on a Chip, 2013, 13(1): 119-125.

DOI：10.1039/c2lc40797c

We describe a technique that measures ultralow interfacial tensions using paramagnetic spheres in a co-flow microfluidic device designed with a magnetic section. Our method involves tuning the distance between the co-flowing interface and the magnet's center, and observing the behavior of the spheres as they approach the liquid-liquid interface-the particles either pass through or are trapped by the interface. Using threshold values of the magnet-to-interface distance, we make estimates of the two-fluid interfacial tension. We demonstrate the effectiveness of this technique for measuring very low interfacial tensions, O(10(-6)-10(-5)) N m(-1), by testing solutions of different surfactant concentrations, and we show that our results are comparable with measurements made using a spinning drop tensiometer.

• 出版日期2013