In situ hard X-ray microscopy of self-assembly in colloidal suspensions

Abstract

An experimental setup combining full-field transmission X-ray microscopy (TXM) and microradian X-ray diffraction (mradXRD) is tested for the in situ study of self-organization of colloidal dispersions of anisotropic particles. Averaged structural information of the samples is determined by mradXRD and local morphology is determined by TXM. Utilization of hard X-rays (12.2 keV) and the ease of switching from diffraction mode to microscopy mode makes such a setup a unique tool, especially for the study of opaque colloidal systems. We demonstrate diffraction patterns together with real space images of the following morphologies: smectic structures in the sediment of colloidal silica rods, the reorientation of a smectic phase of goethite particles in an elevated magnetic field and an interface region between isotropic and ordered phases in a dispersion of colloidal hematite cubes.