Competition between dipolar and steric interactions in swallow-tailed compounds

A new class of swallow-tailed mesogen with the longitudinal dipole moment in the direction of the non-branched 'head' is presented. Mixtures of these compounds with 'conventional' swallow-tailed substances were investigated by polarization microscopy and dielectric measurements. In the mixtures, dipolar and steric interactions favour opposite arrangements of the molecules in the short range order.