IMX Talks - Resolving Hierarchical Structure with X-ray scattering imaging

The function of many materials, from biological tissues to industrial polymers, depends on how their nanoscale building blocks are arranged and aligned within a macroscopic structure, which is essential to understand but difficult to resolve: established high-resolution techniques typically access only small sample volumes, limiting the ability to capture structural or biological variability across extended, heterogeneous samples.
Small-angle X-ray scattering (SAXS) imaging probes local nanostructure by raster-scanning a focused synchrotron beam across a sample. This can be extended to resolve nanostructure orientation voxel-by-voxel in three dimensions in a method called SAXS tensor tomography, which we implement in our open-source software package Mumott. In this presentation, I will show how this approach, and its continued development, can be applied across different material systems.
For injection-molded polymer packaging, SAXS imaging has resolved the layered anisotropic nanostructure important for its mechanical properties, and, combined with industrial processing simulations, the structure formation during thermal processing. Another example is bone, where resolving structure requires both three-dimensional information and sufficient sampling to capture biological variability. Combining 2D and 3D SAXS imaging, we studied regional differences in the human femoral neck, an anatomical site relevant to hip fractures, and, at higher resolution, resolved alternating chirality between neighboring lamellae within individual osteons, a structural feature proposed on mechanical grounds over a century ago.
These examples illustrate how tensor tomography, extended beyond X-ray scattering to wide-angle diffraction and visible-light polarimetry, provides a route to resolving hierarchical structure across a wide range of material systems.

Bio: Marianne Liebi studied food science at ETH Zurich, where she also completed her PhD in 2013, followed by postdoctoral research at the Paul Scherrer Institute and MAX IV Laboratory, Lund. In 2017, she started her own research group at Chalmers University of Technology, Gothenburg, and was appointed in 2021 as tenure-track Assistant Professor at EPFL, where she heads the Laboratory for X-ray Characterization of Materials (cam-X) within the Institute of Materials, in a joint position with the Paul Scherrer Institute (PSI). Her research develops advanced X-ray and optical imaging techniques, centered on small-angle X-ray scattering (SAXS) in 2D and 3D, to resolve the hierarchical structure of materials ranging from fiber composites to pharmaceutical formulations and bone.