Microfluidics Meets Dilute Solution Viscometry: An Undergraduate Laboratory to Determine Polymer Molecular Weight Using a Microviscometer


  • Stephen J. Pety Georgia Institute of Technology
  • Hang Lu Georgia Institute of Technology
  • Yonathan S. Thio Georgia Institute of Technology


This paper describes a student laboratory experiment to determine the molecular weight of a polymer sample by measuring the viscosity of dilute polymer solutions in a PDMS microfluidic viscometer. Sample data are given for aqueous solutions of poly(ethylene oxide) (PEO). A demonstration of shear thinning behavior using the microviscometer is described as well. The results of the implementation of the procedure with undergraduate students are also discussed.

Author Biographies

Stephen J. Pety, Georgia Institute of Technology

Stephen J. Pety received his B.S. in polymer and fiber engineering at the Georgia Institute of Technology in 2010 and is currently a graduate student in materials science and engineering at the University of Illinois at Urbana- Champaign. During his junior and senior years, he was a research assistant working with Dr. Lu and Dr. Thio, where he developed and ran microviscometer laboratory sessions reported here.

Hang Lu, Georgia Institute of Technology

Hang Lu received her B.S. from U. Illinois, Urbana-Champaign, and M.S.C.E.P and Ph.D. from Massachusetts Institute of Technology, all in chemical engineering. She has been an assistant professor in Chemical & Biomolecular Engineering at Georgia Tech since 2005. Among the courses that she has taught are mass and energy balances, transport phenomena, and microfluidics. Her research interest is in microfluidics and applications in neuroscience, cell biology, and biotechnology.

Yonathan S. Thio, Georgia Institute of Technology

Yonathan Thio is an assistant professor in polymer, textile, and fiber engineering. He received his B.S. in chemical engineering and materials science & engineering from the University of California at Berkeley, and his M.S.C.E.P and Ph.D. in chemical engineering from MIT. He joined Georgia Tech in 2005. His research interests are on the structure and properties of polymer composites, block copolymers, and polymer blends. He has taught courses with topics in polymer characterization and structure-properties of polymers.