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.

Structure and Stability of PEG‐ and Mixed PEG‐Layer‐Coated Nanoparticles at High Particle Concentrations Studied In Situ by Small‐Angle X‐Ray Scattering

“…The application of pressure in the kbar range allows probing the volumetric response of soft matter and, in particular, to get insight into the degree of hydration . The response of the different conjugates to pressures up to 4000 bar was monitored with SAXS, which showed a decrease of ligand shell thickness with increasing pressure (Figure c; Figure S3, Supporting Information).…”

Heterogeneous local order in self-assembled nanoparticle films revealed by X-ray cross-correlations

“…The possibility of gaining structural information in dense systems such as liquids or glasses was demonstrated in laser scattering experiments in the 1980s (Clark et al, 1983;Ackerson et al, 1985) and revived by X-ray studies of colloidal glasses (Wochner et al, 2009). In recent years, the potential of XCCA to study structures beyond gðrÞ has been investigated by various theories and simulation studies of two-dimensional systems (Altarelli et al, 2010;Kurta et al, 2012;Lehmkü hler et al, 2014;Malmerberg et al, 2015;Latychevskaia et al, 2015;Martin, 2017;, and shown experimentally for thin colloidal and polymer systems (Schroer et al, 2014(Schroer et al, , 2015Gutt et al, 2014;Liu et al, 2017), liquid crystals (Zaluzhnyy et al, 2016(Zaluzhnyy et al, , 2017 and colloids and nanocrystals (Mendez et al, 2014;Mancini et al, 2016;Schroer, Westermeier et al, 2016;Zaluzhnyy et al, 2017). In addition, cross-correlation has recently been demonstrated as a valuable tool for optimizing scattering signals of noisy data .…”

Pressure-Stimulated Supercrystal Formation in Nanoparticle Suspensions

“…Applying pressure as a homogenous method to induce various structural transformations and phase transitions in pre-ordered nanoparticle assemblies has only recently been done. [23][24][25][26][27] Wu et al…”