Symmetrical fluoroalkylated 4,4’-biphenyl derivatives were synthesized starting from 4,4’-biphenol and characterized. In these compounds, the perfluoroalkyl chain is separated from biphenyl core by two kinds of spacers: allyloxy or ethyl[(3-propyloxy)sulfanyl]acetate moiety. Their thermotropic properties have been examined by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). It has been found that compounds having longer fluoroalkyl chain exhibit higher transition temperatures and melting points. Compounds whose spacer is an allyloxy group exhibit smectic phases, whereas those bearing ethyl[(3-propyloxy)sulfanyl]acetate moiety, show nematic phases.
A. Khalfallah, N. Tounsi, A. Ayari, R. Oueslati, A. Hedhli
Biphenyl, Fluorine, Liquid crystal