SAXS Analyses of PNF Alignment

Transmission SAXS measurements were performed at the P03 beamline,
at PETRAIII storage ring at DESY in Hamburg, Germany.^{46 (link)} The measurements were performed with an X-ray wavelength
λ = 0.97 Å and sample-to-detector distance of 9035 mm.
The scattering patterns were recorded by a single-photon counting
detector (Pilatus 1M, Dectris) with the pixel size of 172 × 172
μm². The beam size was 33 × 27 μm² (horizontal × vertical). The same type of flow channel
was used for the SAXS study as for the spinning experiments, but the
Plexiglas covers were replaced by Kapton films. The flow rates were
the same as the ones used for spinning (4.1, 4.7, and 24.9 mL/h for
the core flow, the first sheath flow, and the second sheath flow,
respectively). The Q2 sheath flow was varied (1.5× and 2×
the initial value) to explore the effect on PNF alignment. Alignment
order parameters of the PNFs were calculated from the scattering patterns
as described in previous work.^{17 (link),21 (link),22 (link)}