Paper Number
SF20 

Session
Surfactants, Foams and Emulsions

Title
A mesoscopic model for nonlinear rheology of entangled wormlike micellar solutions

Presentation Date and Time
October 11, 2022 (Tuesday) 4:25

Track / Room
Track 7 / Ontario

Authors (Click on name to view author profile)

  1. Sato, Takeshi (Institute for Chemical Research, Kyoto University)
  2. Larson, Ronald (University of Michigan-Ann Arbor, Chemical Engineering Department)

Author and Affiliation Lines (in printed abstract book)
Takeshi Sato1 and Ronald Larson2
1Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; 2Chemical Engineering Department, University of Michigan-Ann Arbor, Ann Arbor, MI 48105

Speaker / Presenter 
Sato, Takeshi

Keywords
theoretical methods; computational methods; surfactants

Text of Abstract
We examine nonlinear rheological properties of entangled wormlike micellar solutions under shear and extensional flows using a “micelle slip-spring (MSS) model” [J. Rheol., 66, 639 (2022)], which is based on the slip-spring model for entangled polymers [Likhtman, Macromolecules, 38, 6128 (2005)]. To describe the dynamics of wormlike micelles, breakage and rejoining are addressed in the MSS model. Additionally, to reproduce nonlinear rheological properties, we incorporate the effects of finite extensibility and stress-induced micelle breakage (SIMB) under strong extensional flow into the MSS model. The MSS model can quantitatively predict the shear rheology of the wormlike micellar solution with a moderate number of entanglements (up to Z~7). On the other hand, the extensional behavior of the MSS model have not been tested by comparing with experiments due to the lack of data for wormlike micellar solutions with accessible numbers of entanglements. The shear rheological properties of the MSS model for moderate strain rates, less than the inverse of the average Rouse time, can be fit by the Giesekus model but not by the Phan-Thien/Tanner (PTT) model. This result is in agreement with the experimental finding that the Giesekus model can reproduce shear rheological properties for wormlike micellar solutions. The steady extensional viscosities predicted by the MSS model with SIMB show extension thickening followed by extension thinning, which is qualitatively similar to experimental results. Furthermore, both the Giesekus and the PTT models cannot reproduce the extensional properties of the MSS model. In the future, we will use the MSS model to develop a constitutive model for entangled wormlike micellar solutions.