LAUSR

ABSTRACT We present a mean field theory to describe twist-bend nematic () phases in binary mixtures of banana shaped, such as bent-core or dimer, liquid crystalline (LC) molecules with , where is a twist and is a bend elastic constant. We introduce the free energy for the mixtures by taking into account the director-pitch (DP) coupling of the consisting LC molecules ) and calculate the phase diagrams on the temperature-concentration plane. Our theory demonstrates that the isotropic (I), or para-nematic (), nematic (), and phases appear, depending on the strength of the DP coupling parameter and predicts various phase transitions: the first-order and transitions, and the second-order transition, etc., on the temperature-concentration plane. Our theory has a good agreement with the experimental phase diagrams of the mixtures. Graphical Abstract