Paper Number
PO112 

Session
Poster Session

Title
High-shear-rate signatures of structural transitions of wormlike micelle solutions

Presentation Date and Time
October 12, 2022 (Wednesday) 6:30

Track / Room
Poster Session / Riverwalk A

Authors (Click on name to view author profile)

1. Salipante, Paul (NIST, Polymers and Complex Fluids)
2. Cromer, Michael (Rochester Institute of Technology, School of Mathematical Sciences)
3. Hudson, Steven D. (NIST, Polymers & Complex Fluids)

Author and Affiliation Lines (in printed abstract book)
Paul Salipante¹, Michael Cromer² and Steven D. Hudson^1
1Polymers & Complex Fluids, NIST, Gaithersburg, MD 20899; ²School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY

Speaker / Presenter 
Salipante, Paul

Keywords
experimental methods; theoretical methods; surfactants

Text of Abstract
We investigate the shear-thinning behavior of linear wormlike micelle solutions using temperature-controlled capillary rheology. The viscosity of different semi-dilute concentrations over a range of shear rates from 0.1 1/s to over 10^5 1/s is measured in a range of temperatures where shear banding is not observed. At high shear rates the specific viscosity collapses onto one curve for a given concentration, indicating shear instead of temperature dominates the structure. Two different concentration scaling regimes are observed: semi-dilute weakly entangled concentration scaling at intermediate shear rates and dilute scaling at high shear rates. Two power law behaviors are observed, strong shear thinning above the onset of thinning behavior and weaker shear thinning above approximately 10^3 1/s. We compare the viscosity curves to a living rolie-poly model to describe the response up to intermediate shear and a reactive rod model to describe the response at high shear rates. The models capture the structural transition by coupling the micelle stress to a kinetic equation describing the mean micelle length.