Sectorized crystallization of higher n-alkanes: A high resolution search for oblique chain packing

This is the authors' abstract. We don't add key points for this paper.

Although it was once thought that a major distinction between paraffin and polyethylene lozenge crystals was the sectorization of the latter due to polarization of chain fold surfaces, a recent study has shown that n-paraffins longer than C44H90, but with unfolded chains, also crystallize as sectorized lozenges (Fig. 1) with bright field fringes running along <130> compared to the <130> direction in polyethylene. High resolution electron microscopy and microdiffraction of corrugated polyethylene lozenges, furthermore, have shown that, for the infinite chain folded polymer, these fringes correspond to local oblique chain packings. Although shadowing with C-Pt indicates that the sectorized paraffin lozenges are not corrugated like polyethylene, it was thought that chain obliquity, nevertheless, should also be the cause of the Bragg fringe contrast in Fig. 1. An attempt was made to visualize the detail directly using the SULEIKA cryomicroscope at the Fritz Haber Institute in Berlin, given our previous success in obtaining 2.5Å resolution images of the C44H90 chain packing.