Orientational ordering studies of fluorinated thermotropic liquid crystals by NMR spectroscopy.

TitleOrientational ordering studies of fluorinated thermotropic liquid crystals by NMR spectroscopy.
Publication TypeJournal Article
Year of Publication2014
AuthorsCalucci, L, Geppi, M, Urban, S
JournalMagnetic resonance in chemistry : MRC
Volume52
Pagination625–639
Date Publishedoct
Abstract

Fluorinated calamitic thermotropic liquid crystals represent an important class of materials for high-tech applications, especially in the field of liquid crystal displays. The investigation of orientational ordering in these systems is fundamental owing to the dependence of their applications on the anisotropic nature of macroscopic optical, dielectric, and visco-elastic properties. NMR spectroscopy is the most powerful technique for studying orientational order in liquid crystalline systems at a molecular level thanks to the possibility of exploiting different anisotropic observables (chemical shift, dipolar couplings, and quadrupolar coupling) and nuclei ((2)H, (13)C, and (19)F). In this paper, the basic theory and NMR experiments useful for the investigation of orientational order on fluorinated calamitic liquid crystals are reported, and a review of the literature published on this subject is given. Finally, orientational order parameters determined by NMR data are discussed in comparison to those obtained by optical and dielectric anisotropy measurements.

URLhttp://www.scopus.com/inward/record.url?eid=2-s2.0-84904084299&partnerID=40&md5=ea860d05db000dc0e7e01b3b6ba59007 http://www.ncbi.nlm.nih.gov/pubmed/25042970
DOI10.1002/mrc.4106