Bent-core dopant in a liquid crystal having a reentrant synclinic phase

Small quantities of the bent-core mesogen P-7PIMB were dissolved in an anticlinic liquid crystal consisting of a mixture of left- and right-handed TFMHPOBC, with enantiomer excess X=0.2. The bent-core dopant promotes anticlinic order at higher temperatures, but becomes less effective in suppressing the synclinic phase at the reentrant synclinic transition due to an orientational transition of the dopant within the calamitic TFMHPOBC matrix. Measurements of the anticlinic-synclinic electric-field switching threshold as a function of temperature and dopant concentration facilitate a determination of the component of the anticlinic interaction coefficient U that is due to the bent-core dopant. It is found that the value of U per bent-core molecule is much larger than the corresponding value for a pair of TFMHPOBC molecules in adjacent smectic layers.