Absolute determination of the orientation order quality in a columnar discotic liquid crystal.
Résumé
Simple NMR techniques can provide an abs. quantification of the quality of the orientational order of discotic columnar phases, provided the anisotropic local magnetic interactions are thoroughly characterized. For the prototypical discotic liq. crystal hexapentoxytriphenylene, the authors measure the 13C chem. shift anisotropy of the triphenylene carbons, and use this result to analyze the orientational order, that occurs through a first order phase transition from the high temp. liq. phase, and is almost satd. (order parameter close to 0.85). [on SciFinder(R)]