ABSTRACT:
Two series were prepared4-(alokxy)-N-(4-(heptyloxybenzylidene)aniline (7BAn) and N-(4-alokxybenzylidene)-4-(heptyloxy aniline) (nBA7) the compounds have been identified spectrally (FT-IR, HNMR), and( elemental analysis CHN) the mesomorphic phases were identified by polarized light microscope and measured transition temperatures for compounds in addition to the Differential Scanning Calorimeter (DSC) and when we draw transition temperatures against the number of Carbons atoms for each series it was found the odd-even effect of crystalline phase to smectic phase then to nematic phase then to isotropic phase , and when comparing the liquid crystal behavior for two series it was found that the series (7BAn) all compound exhibit smectic phase in addition to the nematic phase except compound (n = 4) did not show smectic phase, while the series (nBA7) only two compounds show smectic phase (n = 6,7) in addition to the nematic phase. The smectic phase was identified for compound A6 by contact line technique and method of mixing using the reference material: Containing smectic C phase and it was found homogeneity when mixing the two compounds reference and unknowns by observing the mixture under the Polarizing Optical Microscope which indicates that the phase of the unknown is the smectic C phase and when we draw transition temperatures for the binary mixture it was reached Minimal point (Eutectic) at transitional 63C ° at 62% concentration For references substance.