Étude par chromatographie en phase gazeuse de nouveaux composés cristaux liquides nématiques à chaîne latérale

Abstract The analytic performances of three stationary phases ‘liquid crystal’ to side chain have been presented. Mesogenic compounds studied in this work are: – 3-CH 3 : 2-(3-methylbenzyloxy)-3- n -hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene; – 4-CH 3 : 2-(4-methylbenzyloxy)-3- n -hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene; – 3-Cl : 2-(3-chlorobenzyloxy)-3- n -hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene. The originality of these three compounds is essentially due to the presence of a substituted benzyloxy group, more voluminous, which is close to the n -hexyloxy flexible chain. Retention properties of these new liquid crystals have been characterised by the capillary column treated and impregnated according to the dynamic method. The position, ortho or para, of the methyl group on benzyloxy does not interfere significantly on the retention mechanism. In the case of the replacement of the methyl group by a halogen atom (chlorine), we noticed a radical change of the retention properties.