Paper Number
EF13 

Session
Emulsions, Foams and Interfacial Rheology

Title
Elasticity of microscale volumes of viscoelastic soft matter by cavitation rheometry

Presentation Date and Time
October 8, 2014 (Wednesday) 2:20

Track / Room
Track 6 / Washington C

Authors (Click on name to view author profile)

1. Pavlovsky, Leonid (University of Michigan, Chemical Engineering)
2. Ganesan, Mahesh (University of Michigan, Chemical Engineering)
3. Younger, John G. (University of Michigan, Emergency Medicine)
4. Solomon, Michael J. (University of Michigan, Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Leonid Pavlovsky¹, Mahesh Ganesan¹, John G. Younger², and Michael J. Solomon^1
1Chemical Engineering, University of Michigan, Ann Arbor, MI 48109; ²Emergency Medicine, University of Michigan, Ann Arbor, MI 48109

Speaker / Presenter 
Solomon, Michael J.

Text of Abstract
We evaluate the application of cavitation rheometry to characterize the elasticity of soft, viscoelastic liquids that may be confined to volumes as small as 1 µL. Cavitation rheometry, a technique developed by Zimberlin et. al (Soft Matter, 3(6), 765-767, 2007), is a simple, rapid method to extract the elastic modulus of a material, E, by measuring the pressure necessary to create a bubble, or cavity, within it. This pressure has been shown to be an estimate of the elastic modulus in a limit where the bubble size is small relative to size of the specimen and the material is purely elastic. We extend this method in three ways for possible applications in high throughput materials characterization and in vivo tissue diagnostics. First, we show that viscoelastic samples can be approximated with the purely elastic neo-Hookean model provided that the time scale of the cavity formation is measured. Second, we extend the cavitation rheometry method to accommodate cases in which the sample size is no longer large relative to the cavity dimension. Finally, we implement cavitation rheometry to show that the new theory accurately measures the elastic modulus of viscoelastic samples with volumes ranging from 4 mL to as low as 1 µL.