Structure and Mechanics of Polymer Materials

Investigating the micro- and nanostructure of polymer materials have been of interest in recent decades since it defines the functionality of the material. Understanding the structure is key to optimize material usage and to further increase the quality of the product.

We are using a combination of different X-ray techniques to investigate the polymer material at different length scales. Small- and wide-angle X-ray scattering (SAXS/WAXS) in scanning mode (e.g. at cSAXS) allows to probe the variation of structures formed in semi-crystalline materials, such as sperhulites, elongated spherulites or the highly anisotropic shish-kebab structure. Scanning transmission X-ray microscopy (STXM) with X-ray near-edge absorption (XANES) contrast (e.g. at Pollux) allows to study chemical contrast with very high resolution. Ptychographic tomography allows for 3D structure with resolution below 100 nm, and for sensitive polymer material the measurement under cryo-condition using OMNY is beneficial.

The development in industrial packaging strives to use virtual simulations instead of try-and-error testing to further improve their materials and test new shapes and materials. However, in order to predict mechanical properties with improved accuracy, the detailed material structure need to be included into the simulations. Polymers are often anisotropic materials which properties are highly effected by processing conditions and can therefore be hard to predict. In an industrial collaboration with Tetra Pak® we are using SAXS imaging to study the structure of polyethylene with varying processing conditions. With the proposed structure, we can explain the anisotropic mechanical properties observed in the material, which shows its potential to be used in combination with simulation tools for improved virtual product development. This project is conducted at the Chalmers University of Technology in Gothenburg, Sweden.

Within the Swedish VINNOVA competence centre FibRe which is a research consortium between academia (Chalmers University of Technology and KTH Royal Institute of Technology together) industry and public organization partners, we are responsible for the use of X-ray methods for the characterization of lignocellulose based thermoplastics. In particular we are interested in characterizing local chemical modification introduced to make the material thermoplastic using STXM. This project is conducted at the Chalmers University of Technology in Gothenburg, Sweden.

Pharmaceutical formulations can be utilized as a method for controlled release, for improving dissolution properties and to enhance the bioavailability of an active substance. A key issue to understand and design the functional mechanism of these formulations is to understand its structure and morphology. We are using SAXS/WAXS imaging, ptychographic tomography and STXM to investigate the structure from the micro to nanoscale and to relate the functional properties of the compound to its morphology. This project is conducted at the Chalmers University of Technology in Gothenburg, Sweden.

In order to understand hierarchical structure of polymer electrolyte fuel cell catalysts a correlation study using SAXS/WAXS imaging an ptychographic tomography is used. This project is conducted in a close collaboration with the CXS group at PSI.