title: Investigating the microstructure of a yield-stress fluid by light scattering.
abstract: We report the results of an experimental study of the microstructure of dispersions of Carbopol ETD 2050, a model yield-stress fluid. Using two different light scattering instruments, measurements were made over three decades in scattering wave vector, from 0.02 to 25 μm⁻¹. These measurements reveal microstructure characterized by two length scales: a longer length scale, 6 μm and larger, that depends on Carbopol concentration and the pH of the dispersion and a shorter length scale of approximately 400 nm that is independent of both sample concentration and pH. We relate these results to shear rheology measurement of the yield stress of these materials.
authors.affiliation: Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A1S6, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Lee
authors.forename: Iris A
authors.initials: IA
authors.lastname: Gutowski
authors.forename: Arthur E
authors.initials: AE
authors.lastname: Bailey
authors.forename: Laurent
authors.initials: L
authors.lastname: Rubatat
authors.forename: John R
authors.initials: JR
authors.lastname: de Bruyn
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Frisken
mesh_terms: D000180:Acrylic Resins; D002621:Chemistry / Q000379:methods; D004655:Emulsions; D004867:Equipment Design; D006863:Hydrogen-Ion Concentration; D008027:Light; D008970:Molecular Weight; D011145:Polyvinyls / Q000737:chemistry*; D012212:Rheology; D012542:Scattering, Radiation; D033081:Shear Strength; D013314:Stress, Mechanical
chemical_list: D000180:Acrylic Resins; D004655:Emulsions; D011145:Polyvinyls; C006912:carboxypolymethylene