Orientational ordering studies of fluorinated thermotropic liquid crystals by NMR spectroscopy21. (10th July 2014)

• Record Type: Journal Article
• Authors: Calucci, Lucia; Geppi, Marco; Urban, Stanislaw; Dong, Ronald Y.
• Is Part Of: Magnetic resonance in chemistry. Volume 52:Number 10(2014:Oct.)
• Page Start: 625
• Page End: 639
• Publication Date: 2014-07-10
• Subjects: Nuclear magnetic resonance spectroscopy -- Periodicals; Chemistry, Organic -- Periodicals; Magnetic resonance -- Periodicals; 538.36
• DOI: 10.1002/mrc.4106
• Languages: English
• ISSNs: 0749-1581

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>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 (²H, ¹³C, and ¹⁹F). 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. Copyright © 2014 John Wiley &amp; Sons, Ltd.</p> </abstract>