title: Colloidal crystallite suspensions studied by high pressure small angle x-ray scattering.
abstract: We report on high pressure small angle x-ray scattering on suspensions of colloidal crystallites in water. The crystallites made out of charge-stabilized poly-acrylate particles exhibit a complex pressure dependence which is based on the specific pressure properties of the suspending medium water. The dominant effect is a compression of the crystallites caused by the compression of the water. In addition, we find indications that also the electrostatic properties of the system, i.e. the particle charge and the dissociation of ions, might play a role for the pressure dependence of the samples. The data further suggest that crystallites in a metastable state induced by shear-induced melting can relax to a similar structural state upon the application of pressure and dilution with water. X-ray cross correlation analysis of the two-dimensional scattering patterns indicates a pressure-dependent increase of the orientational order of the crystallites correlated with growth of these in the suspension. This study underlines the potential of pressure as a very relevant parameter to understand colloidal crystallite systems in aqueous suspension.
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: M A
authors.initials: MA
authors.lastname: Schroer
authors.affiliation: Max-Planck-Institut für Struktur und Dynamik der Materie, CFEL, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Westermeier
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Lehmkühler
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Conrad
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Schavkan
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: A V
authors.initials: AV
authors.lastname: Zozulya
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Fischer
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Roseker
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Sprung
authors.affiliation: Department of Physics, University of Siegen, Walter-Flex-Str. 3, 57072 Siegen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Gutt
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Grübel