Date of Award
8-2018
Document Type
Dissertation
Degree Name
Ph.D. in Physics
Department
Physics and Astronomy
First Advisor
Cecille Labuda
Second Advisor
Joel Mobley
Third Advisor
Josh Gladden
Relational Format
Dissertation/thesis
Abstract
Wormlike micellar fluids, which flow when subjected to long-term stresses, are mechanically viscoelastic over shorter durations and can support shear waves. These fluids are birefringent under shear, allowing the study of shear wave propagation using both optical and acoustic modalities. Microstructural phase transitions of the micelles are temperature dependent and can manifest as sharp changes in the shear wave speed as a function of temperature. In this work, the behavior of shear waves in a fluid consisting of hexadecyltrimethylammonium bromide (CTAB) and sodium salicylate (NaSal) combined in a 5:3 ratio in a 200 mM concentration is studied. The temperature-dependent microstructural phase transitions were investigated in the temperature range of 4 – 40 °C. First, the temperature dependent behavior of mechanically generated shear waves was studied to identify these microstructural phase transitions and the implications of the shear wave speed variation over the temperature range were examined by measuring thermal properties. The thermal and spectral behavior of ultrasonically generated shear waves in the fluid was also studied by pulsing a HIFU (high intensity focused ultrasound) beam and generating a train of shear waves. The temperature and frequency dependent behavior was correlated with the rheological and microstructural properties of the WM fluid.
Recommended Citation
Dayavansha, E. G. Sunethra K., "Frequency and Temperature Dependence of Shear Wave Speed with Rheological Properties in a Micellar Fluid" (2018). Electronic Theses and Dissertations. 2780.
https://egrove.olemiss.edu/etd/2780
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