ON THE MOLECULAR-ORGANIZATION WITHIN THE NEMATIC PHASE OF LIQUID-CRYSTAL DIMERS

It has been reported that the biaxiality in the Saupe ordering matrix of a solute dissolved in liquid-crystal dimers is greater when the flexible spacer contains an even number of atoms than when there is an odd number. This result is unexpected because of the greater molecular biaxiality of odd dimers. We have, therefore, investigated the ordering of another solute, [H-2(10)]anthracene, dissolved in three pairs of liquid-crystal dimers, all of which have both odd and even spacers, using deuterium NMR spectroscopy. Our results confirm those of the original study. To understand the enhanced biaxiality of the solute ordering matrix for dimers with an even spacer we propose a new model of the molecular organisation in liquid-crystal dimers with odd and even spacers.