Polarized resonant soft x-ray scattering (RSoXS) can leverage contrast between domains in mass, chemical bonds, and chain orientation to characterize polymer thin films. Although mass and chemical contrast can be predicted from the absorption spectra, the origins of orienta-tional contrast are not fully understood. For example, in the case where one domain is crystalline, it is not obvious how the total crystallinity will affect the anisotropy. Using a simple calculation, we predict polarized RSoXS of model structures and compare with experiment. Through experiments and simulations, we demonstrate that scattering anisotropy is not monotonically related to local order but instead peaks when 50% of domains have aligned chains, i.e., when the sample is 50% crystalline.
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Financial support from the National Science Foundation under Award DMR-1626566 is acknowledged. Financial support from the Office of Naval Research under Grant N000141410532 is also acknowledged. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
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Litofsky, J.H., Gomez, E.D. Connecting soft x-ray anisotropy with local order in conjugated polymers. MRS Communications 9, 1168–1173 (2019). https://doi.org/10.1557/mrc.2019.119