Paper Number
FE24 

Session
Foams, Emulsions, Surfactants, and Micelles

Title
Medium amplitude parallel superposition (MAPS) rheology of a wormlike micellar solution

Presentation Date and Time
October 12, 2021 (Tuesday) 3:45

Track / Room
Track 3 / Meeting Room A-B

Authors (Click on name to view author profile)

  1. Lennon, Kyle R. (Massachusetts Institute of Technology, Department of Chemical Engineering)
  2. McKinley, Gareth H. (Massachusetts Institute of Technology, Mechanical Engineering)
  3. Swan, James W. (Massachusetts Institute of Technology, Department of Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Kyle R. Lennon1, Gareth H. McKinley2 and James W. Swan1
1Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142; 2Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA

Speaker / Presenter 
Lennon, Kyle R.

Keywords
experimental methods; theoretical methods; applied rheology; micelles; rheology methods

Text of Abstract
We investigate the weakly nonlinear, simple shear rheology of a wormlike micellar solution using a recently developed multi-tone experimental protocol and the framework of medium amplitude parallel superposition (MAPS) rheology. These data-rich experiments probe intrinsic nonlinearities of viscoelastic materials under a broad range of conditions and deformation time-scales. MAPS rheology defines weakly nonlinear material properties, such as the third order complex compliance, that are measured directly by multi-tone experiments, and may be compared to analytical solutions of constitutive models. We compare our data for a CPyCl micellar solution to the predictions of a reptation-reaction constitutive model, which treats micelles as linear polymers that can break apart and recombine in solution. Despite the apparent complexity of this constitutive model, we are able to solve for its MAPS response analytically, and formulate a convex parameter estimation problem from the weakly nonlinear data. The result of this parameter estimation reveals new insight into how these breakage and recombination processes are affected by shear, and demonstrates the importance of using information-rich data to infer precise estimates of model parameters.