title: X-ray scattering in the vorticity direction and rheometry from confined fluids.
abstract: An X-ray flexure-based microgap rheometer (X-FMR) has been designed for combining rheology and in situ small-angle X-ray scattering from the vorticity plane. The gap distance can be varied continuously from 500 μm down to several μm, which provides the unique possibility to generate a strong confinement for many complex fluids. A singular advantage of this setup is the possibility to directly probe the vorticity direction of the flow field with a microfocus X-ray beam and to probe the structural response of the fluid to combined shear and confinement in the vorticity plane. The sliding-plate setup operates over a wide range of shear rates of γ = 10(-3)-10(3) s(-1) and strains in the range of 10(-4)-10(2). The flexure-based bearing maintains the plate parallelism within 10(-5) rad. The X-FMR requires very small sample volumes on the order of 10 μl. The applicability of the device is demonstrated here with limited examples of a nematic suspension of fd virus (rods), and a crystalline suspension containing sterically stabilized polystyrene-butylacrylate latex particles.
authors.affiliation: Department of Chemical Engineering, KU Leuven, 3001 Leuven, Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Pfleiderer
authors.affiliation: Department of Chemical Engineering, KU Leuven, 3001 Leuven, Belgium.
authors.forename: Seung Jae
authors.initials: SJ
authors.lastname: Baik
authors.affiliation: Department of Chemical Engineering, KU Leuven, 3001 Leuven, Belgium.
authors.forename: Zhenkun
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Chemical Engineering, KU Leuven, 3001 Leuven, Belgium.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Vleminckx
authors.affiliation: Institute of Complex Systems (ICS-3), Forschungszentrum Jülich, 52425 Jülich, Germany.
authors.forename: Minne Paul
authors.initials: MP
authors.lastname: Lettinga
authors.affiliation: Centre de Recherche Paul-Pascal, CNRS - Université de Bordeaux, 33600 Pessac, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Grelet
authors.affiliation: Department of Chemical Engineering, KU Leuven, 3001 Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Vermant
authors.affiliation: Department of Chemical Engineering, KU Leuven, 3001 Leuven, Belgium.
authors.forename: Christian
authors.initials: C
authors.lastname: Clasen