The synthesis and mesomorphic properties of some novel antiferroelectric liquid crystals

Several esters have been synthesised that exhibit the antiferroelectric sme ctic C phase. The core structures, like virtually all antiferroelectric mat erials, are very similar to that of MHPOBC. Lateral fluoro substituents hav e been used to reduce melting points and to investigate their effect on mes omorphic properties, spontaneous polarisation and tilt angle. A new device format reported by Lagerwall requires antiferroelectric liquid crystals wit h a 450 degrees tilt angle. Novel antiferroelectric materials were prepared with fluoro substituents in lateral positions and in a terminal chain to p rovide low melting points, high antiferroelectric phase stability, high spo ntaneous polarisation and tilt angles of up to 45 degrees. The synthetic ro utes to the novel materials are discussed, and the transition temperatures, tilt angles and spontaneous polarisations are compared to those of known m aterials.