Simultaneous Slit Rheometry and In Situ Neutron Scattering

Published: February 12, 2018


Javen S. Weston, D. P. Seeman, Daniel L. Blair, Paul Salipante, Steven D. Hudson, Kathleen M Weigandt


In situ measurement of fluid structure during flow, e.g., by neutron scattering, is key to understanding the relationship between structure and rheology. For some applications, structures at high shear rates heretofore unreachable are of particular interest. Here we report development of a flow-cell based slit rheometer for neutron scattering (υRheoSANS). The devices were used to measure the structure of a semidilute surfactant solution of rod-like micelles during flow. Analysis of the rheometry and scattering data allows isolation of the scattering signal from the high-shear, near-wall region of the flow cell. The reported results agree with those from the existing Couette-based RheoSANS instrument. The wormlike micelles exhibit an alignment transition at Weissenberg number Wi {approximately equal} 1, coinciding with the onset of shear thinning. This transition is followed by a peak in micelle alignment at a higher shear rate, after which the degree of alignment decreases moderately. This technique can achieve higher shear rates than existing RheoSANS techniques, expanding the ability to study the structure of complex fluids at elevated shear rates.
Citation: Rheologica Acta
Volume: 57
Pub Type: Journals


Rheology, rheoSANS, SANS
Created February 12, 2018, Updated February 23, 2018