Effect of flexible bimesogen dopant on the stability of the anticlinic liquid-crystal phase.

Small quantities of the floppy bimesogen di(4PPB5)3Si were dissolved in an anticlinic liquid crystal consisting of a mixture of left-handed and right-handed TFMHPOBC, with enantiomer excess X=0.2 . The bimesogen dopant was found to promote anticlinic order with an anticlinic interaction coefficient per molecule udopant smaller than, but of the same order as, that of the rigid bent-core dopant P-7PIMB. For both dopants udopant was found to be much larger than that due to a pair of TFMHPOBC molecules in adjacent layers. The results are examined in terms of both the flexibility of the group linking the two legs of each dopant, as well as their chemical structure.