A Comparative Investigation into the Mesomorphism of Series of Aromatic Naphthalen-2-yl 4-(Alkoxy) Benzoate and Naphthalen-1-yl 4-(Alkoxy) Benzoate Materials

A homologous sequence of aromatic ester materials' mesogenic characteristics are investigated. This study is aimed at comparing the mesomorphic behavior of the series described herein with mesogenic materials we prepared and studied earlier. Single tail and double tail materials were synthesized for this comparative study. By using differential scanning calorimetry and polarized light microscopy, the phase sequences and transition temperatures were determined. Only compounds with a single tail and an ester connected at position 2 of the naphthalene exhibit mesogenic behaviour. Two materials (ZH 29 & ZH 32) possess a monophasic nematic phase and another two materials (ZH 14 & ZH 35) display biphasic nematic and smectic (A) phases. The materials with the ester attached to naphthalene at position 1 do not display any mesogenic behavior. The materials with two alkoxy chains bonded to the benzoate ester do not display any mesogenic behavior as well.