Medium Amplitude Parallel Superposition (MAPS) Rheology of a Wormlike Micellar Solution

TL;DR

This study combines modeling and experiments to explore the weakly nonlinear rheology of wormlike micellar solutions using MAPS rheology, revealing how shear influences micelle breakage and recombination.

Contribution

It introduces the use of MAPS rheology to characterize micellar solutions and demonstrates how rich data can improve model parameter estimation.

Findings

MAPS rheology effectively characterizes third order complex compliance.

Shear influences micelle breakage and recombination processes.

Rich data improves accuracy of model parameter inference.

Abstract

The weakly nonlinear rheology of a surfactant solution of wormlike micelles is investigated from both a modeling and experimental perspective using the framework of medium amplitude parallel superposition (MAPS) rheology. MAPS rheology defines material functions, such as the third order complex compliance, which span the entire weakly nonlinear response space of viscoelastic materials to simple shear deformations. Three-tone oscillatory shear deformations are applied to obtain feature-rich data characterizing the third order complex compliance with high data throughput. Here, data for a CPyCl solution are compared to the analytical solution for the MAPS response of a reptation-reaction constitutive model, which treats micelles as linear polymers that can break apart and recombine in solution. Regression of the data to the model predictions provides 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.