INFLUENCE OF STRUCTURE ON SMECTIC-A-SMECTIC-A PHASE-SEPARATION

The critical temperature at the consolute point where two smectic A ph ases of different compositions phase separate has been measured for bi nary systems which combine one compound from a newly synthesized serie s of fluorinated mesogens with one homologue from the commercially ava ilable cyanobiphenyl family. Taking advantage of the regular evolution of the layer spacings within a series of homologues, this systematic analysis identifies a clear connection between miscibility and differe nce in layer spacings of the smectic A phases of the pure compounds. H owever, additional data obtained on significantly different systems sh ow the non-universal character of this analysis and suggest that facto rs in addition to this structural difference are relevant to this phen omenon.