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. Author manuscript; available in PMC: 2015 Oct 21.
Published in final edited form as: Nat Commun. 2015 Sep 25;6:8394. doi: 10.1038/ncomms9394

Figure 2. NEXAFS spectroscopy and GIWAXS scattering patterns from bar-coated samples.

Figure 2

a-b) Angle-resolved NEXAFS measurements of a 10 nm (thick) bar-coated film; to probe the degree of in-plane alignment of the polymer transition dipole moments (TDMs), the NEXAFS spectra were recorded as a function of azimuthal angle, rotating the sample with respect to a normally incident x-ray beam. The TDMs of the carbon 1s → π* transitions between 284 to 286 eV are oriented perpendicular to the conjugated backbone with the dichroism, thus providing an indirect measure of the degree of polymer backbone alignment at the film surface. Strong dichroism is observed for the peaks corresponding to other TDMs, e.g. C 1s to C-H σ* (287.4 eV) and C 1s to C-C σ* (~ 292 eV and 302 eV), indicating strong orientational alignment of side chains as well as the polymer backbone. c-d) Angle-resolved NEXAFS measurements of a submonolayer (thin) bar-coated sample; e-f) 2D GIWAXS scattering patterns of bar-coated film (thick) recorded with the x-ray beam incident (e) parallel and (f) perpendicular to the coating direction.