Small-angle X-ray scattering (SAXS) is a highly effective tool for non-destructive analysis of anisotropy in suspensions and colloids. SAXS can provide information of the size and shape of particles in suspension, and contains information on the ordering and structure of the internal particle arrangement. Such information is particularly relevant for clay materials, whose mechanical response is highly dependent on the microstructure. Here, a new approach is introduced for analyzing SAXS images, focusing on the extraction of orientation degrees and preferred angles. This objective characterisation of the internal material fabric is applied to clay slurries sheared in a Couette cell under various shear rates and similar relative liquidity for three different clay minerals: kaolinite, halloysite and Na-montmorillonite. Kaolinite exhibits significantly higher anisotropy compared to halloysite and Na-montmorillonite, and reaches its maximum anisotropy under a lower shear rate. Beyond clay science, the methodology developed in this study opens new possibilities in broader materials science and nanotechnology for studying the orientation of other particles and internal fabrics.
- The technique is explained in detail in
Code for ellipse fitting.m. - Raw data files are provided in the
Examples/folder. - License: MIT (see
LICENSE).
If you use this technique for research, please cite: Bui, V. K., et al., “Anisotropy analysis of clay microstructure under shear using small angle Xray scattering.”