New bent‐shaped liquid crystalline derivatives of 2,7‐dihydroxynaphthalene containing lateral bromine atoms

Abstract

New banana‐shaped mesogens with a naphthalene central ring were synthesised. The presence of a lateral substituent, i.e. a bromine atom in a phenyl group localised near the central naphthalenic ring, drastically decreases the clearing and melting temperatures of these materials and favours formation of a nematic phase. The smectic phase is observed only for the longest homologues (for n>12). The observed smectic B phase is of the antiferroelectric, synclinic type in a virgin sample, but when relaxed after application of an electric field, an antiferroelectric, anticlinic structure with 45° tilt is formed, as suggested by texture with zero birefringence.

Keywords:

• 2,7‐dihydroxynaphtalene esters
• banana‐shaped mesogens
• spontaneous polarisation