Study of binary systems inducing mesophase and determination of latent transition temperature

Matushri Virbaima Mahila College, Rajkot-360 001, India Manuscript received 28 January 1999, revised 30 August 1999, accepted 3 March 2000 Five binary systems consisting of common component as nematogen (A), viz. p-(p'·n·propyloxybenzoyloxy)anisole is mixed with un· common component (B) (nonmesogen or monotropic nematic), para-substituted Schiff bases, viz. X-C6H4-CH=N-C6H4-Y, where X = CH3, Cl, OCH3 and Y = OCH3 or OC2H5. Interesting results are obtained as (i) nematic mesophase maintained monotropically and enantiotropically from the binary systems with nonmesogen (B), (ii) smectic mesophase induced and nematic mesophase main· tained from binary system comprising monotropic nematic component (B). Polarity and polarizability of terminal groups of component (B) play an important role in enhancing the liquid crystallinity. The group efficiency order is derived as, OC2H5 > CH3 = Cl. Latent transition temperatures of components (B) for smectic and nematic mesophases are determined