Dielectric and electro-optic properties of cybotactic nematic phase in hydrogen-bonded liquid crystals

Publication date: Available online 19 February 2020Source: Journal of Molecular LiquidsAuthor(s): Tayssir Missaoui, Ines Ben Amor, Taoufik Soltani, Hafedh Ben Ouada, Erwann Jeanneau, Yves ChevalierAbstractThe new compounds 4-decyloxy-2-fluorobenzoic acid and 4-dodecyloxy-2-fluorobenzoic acid display hydrogen-bonded liquid crystals (HBLC) of smectic and nematic phases. Their phase behavior established using polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) consistently occurs as the sequence upon cooling: Isotropic liquid – Nematic – SmC – crystalline solid. The dielectric study in the nematic phase shows a single relaxation process at low frequency characteristic of a cybotactic nematic phase. The optical properties of the nematic phase show a decrease of birefringence as alkyl chain length increases in the high-temperature part of the nematic domain, which reveals a decrease of order parameter for longer chains.Graphical abstract
Source: Journal of Molecular Liquids - Category: Molecular Biology Source Type: research