Microfluidic ultralow interfacial tensiometry with magnetic particles

Scott S.H. Tsai, Jason S. Wexler, Jiandi Wan, Howard A. Stone

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)119-125
Number of pages7
JournalLab on a Chip
Issue number1
StatePublished - Jan 7 2013

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Bioengineering
  • Biochemistry
  • Biomedical Engineering


Dive into the research topics of 'Microfluidic ultralow interfacial tensiometry with magnetic particles'. Together they form a unique fingerprint.

Cite this