Polarized Resonant Soft X-ray scattering reveals interfacial molecular orientation in amorphous regions of multi-phase organic films.

Molecular orientation at interfaces in multi-component and semi-crystalline films can significantly affect the material's function, but it can be difficult to quantify. The interaction between oriented chemical bonds and polarized resonant soft X-rays results in scattering (p-RSoXS) that is sensitive to interfacial molecular orientation, in addition to chemical composition. We use p-RSoXS to measure both a two-component, phase separated vapor-deposited glass, and a semi-crystalline polymer. For both systems, we use a forward-scattering GPU-accelerated simulation based on high-quality real space imaging to identify a real-space model that produces a combination of compositional, orientational, and vacuum scattering contrast that is consistent with experiment. This approach allows us to measure the direction, spatial extent, and magnitude of orientation in molecules at amorphous-amorphous and amorphous-crystalline interfaces. These results provide insight into the effect of processing conditions on the structure and properties of non-equilibrium materials.