Abstract
We report the observation of a partially bilayer smectic A phase in n-dodecyl-4-(4-ethoxybenzylidene amino)-α-methylcinnamate, a compound which does not possess a strongly polar cyano or nitro end group. The ratio of the layer spacing to molecular length is found to be about 1.12. The dielectric anisotropy versus temperature plot exhibits a reversal of sign in the smectic A phase revealing a pronounced dipole-dipole correlation in the longitudinal direction. Such a sign reversal has probably been observed for the first time in a pure smectogenic material.