Ferroelectricity of a smectic C liquid crystal with doping-induced helical structure

The SmC phase of 7S5 (4-n-pentylphenyl-4'-n-heptyloxythiobenzoate) has been transformed into a ferroelectric SmC* phase by doping with varying amounts of the chiral S811 (4-(4 hexyloxybenzoyloxy)-1-methylheptylbenzoate). Optical microscopy and DSC have been used to obtain the complete phase diagram. Above 4wt% of S811 a SmA phase is placed between N* and SmC* and above 10wt% crystallization hinders the study of SmC*. Switching angles, spontaneous polarization and switching times are presented for mixtures of 5, 7, and 10wt% S811. Polyimide coating and uniform shearing are applied for sample alignment.

Notes

Now VDO Adolf Schindling AG, Schwalbach/Taunus