Phase diagrams of binary mixtures of liquid crystals and rodlike polymers in the presence of an external field

摘要

We theoretically study phase separations in mixtures of a low molecular-weight-liquid crystalline molecule (LC) and a rigid-rodlike polymer (rod) under an external field, such as magnetic or electric fields. By taking into account two orientational order parameters of the rod and the LC, we define four nematic phases (N0, N1, N2, N3) on the temperature-concentration plane. Depending on the sign of the dielectric anisotropy Δ∈_i of the rod (i = 1) and LC(i = 2), we examine the phase behavior of rod/LC mixtures in the case of Δ∈_1 >0, Δ∈_2 >0 (a), Δ∈_1< 0, Δ∈_2 >0 (b), Δ∈_1 >0, Δ∈_2< 0 (c), and Δ∈_1< 0, Δ∈_2< 0 (d). We predict a variety of phase separations induced by an external field.