Abstract
This work aims to determine how the nematic twist-bend phase (N(TB)) of bismesogens containing two rigid parts of cyanobiphenyls connected with a linking chain containing n = 7, 9, and 11 methylene groups behaves in mixtures with structurally similar cyanobiphenyls nCB, n = 4-12, 14. The whole phase diagrams are presented for the CB7CB-nCB system. For the other systems, CB9CB-nCB and CB11CB-nCB, only curves corresponding to N(TB)-N phase transition are presented. Based on the temperature-concentration range of the existence of N(TB) phase, it was established that an increase in the alkyl chain length of CBnCB causes an increase in the stability of the N(TB) phase. But surprisingly, an increase in the alkyl chain length of nCB compounds does not change the slope of the N(TB)-N equilibrium line on phase diagrams. It is slightly bigger when the nCB compound has the same length of alkyl chain as the length of the linking group of a bismesogen. XRD studies were carried out for two mixtures.