Microfluidic Ultralow Interfacial Tensiometry: Accurate and Low Cost

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Microfluidic Ultralow Interfacial Tensiometry: Accurate and Low Cost


Princeton Docket # 12-2778

Researchers at Princeton University have developed a novel technique to measure ultralow interfacial tensions using paramagnetic spheres in a microfluidic co-flow device.  The resulting tensiometry device is accurate, low cost, compact in size, and easy to integrate.

Fluid systems that have ultralow interfacial tensions appear in a range of different applications, including uses in oil and food industries.  However, quantifying ultralow interfacial tensions practically and accurately has remained challenging.  Traditional force tensiometry methods such as Wilhelmy Plate and Du Noüy Ring are not suitable because it is difficult to resolve the small forces experienced by the probes at the interface of ultralow interfacial tension fluids.  Measuring very low interfacial tensions using the spinning drop method is also not ideal since the droplets equilibrate very slowly, making it challenging to determine when to make the measurement.

By using a balance of magnetic and surface forces on the spheres in a microfluidic co-flow, Princeton researchers can measure two-fluid interfacial tension.  The effectiveness of this technique has been experimentally demonstrated by measuring very low interfacial tensions (10-3 ¿ 10-2 mN/m) in solutions of different surfactant concentrations.  It is anticipated that this technique may be scaled up to measure up to 1 mN/m.



Microfluidic ultralow interfacial tensiometer



Accurate in the measuring range of 10-3 ¿ 10-2 mN/m

Low cost (each microfludic chip costs approximately $10 to produce)

Easy integration into existing lab equipment (a microscope and pumps)

Portable (by integration into a portable lab-on-a-chip device)

Instant measurement (no equilibration time required)




Tsai SSH, Wexler JS, Wan J, and Stone HA.  Microfluidic Ultralow Interfacial Tensiometry by Magnetic Forcing.  Lab Chip. 


Faculty Inventor

Howard Stone is the Donald R. Dixon '69 and Elizabeth W. Dixon Professor in Mechanical and Aerospace Engineering at Princeton University.  His research has been concerned with a variety of fundamental problems in fluid motions dominated by viscosity, so-called low Reynolds number flows, and has frequently featured a combination of theory, computer simulation and modeling, and experiments to provide a quantitative understanding of the flow phenomenon under investigation.  Prof. Stone is the recipient of the most prestigious fluid mechanics prize, the Batchelor Prize 2008, for best research in fluid mechanics in the last ten years.  He is also part of the Class of 2011 inductees of the American Academy of Arts and Sciences.

Intellectual Property status

Patent protection is pending.



Michael Tyerech

Princeton University Office of Technology Licensing

(609) 258-6762 tyerech@princeton.edu


Patent Information:
For Information, Contact:
Michael Tyerech
former Princeton Sr. Licensing Associate
Princeton University
Scott Shao Hsiang Tsai
Jason Wexler
Jiandi Wan
Howard Stone