Phase transitions in three-component mixtures containing alkoxybenzoic acids with a chiral material

Abstract

ABSTRACTThe paper contains results of investigation into phase polymorphism and electro-optical properties of ternary mixtures composed of two mesogenic 4-n-alkoxybenzoic acids: dodecyloxybenzoic acid (12OB) and tetradecyloxybenzoic acid (14OB) with a molar ratio of 1:1 and chiral liquid crystal (S)-4-(1 methylheptyloxy)biphenyl-4'-(heptyloxyphenyl)-4-carboxylate (MHOBOPO7). Mixtures with the following contents of the mole fraction of the chiral compound in relation to the content of acids OB: were prepared; A–0.50; B–0.33; C–0.20; D–0.10; E–0.05; F–0.025. The polymorphism of the mixtures was determined by three complementary methods: Differential Scanning Calorimetry (DSC), Transmitted Light Intensity (TLI) and Polarizing Optical Microscope (POM). The extent of the smectic phase C and the nematic phase were increased. The smectic C phases in mixtures A, B, C, D showed a clear ferroelectric character. Ferroelectric properties of mixtures were determined by electro-optical methods.