Optical anisotropy of retarder film made from mixtures of rodlike and T-shaped reactive molecules: dependence on the chemical structure of T-shaped molecules

Five kinds of T-shaped reactive molecules were newly synthesized for optical retarder films. The retarder films were fabricated using the mixtures of rodlike reactive mesogen (RM) and the T-shaped molecules. The effect of the chemical structure of the T-shaped molecules on the optical anisotropy of the retarder films was investigated. The retarder films with the T-shaped molecules resulted in a greater magnitude of an in-plane retardation. Among the five kinds of the T-shaped molecules, the molecule with five benzene rings along the longitudinal direction and two benzene rings along the lateral molecular direction showed the widest liquid crystalline phase and the largest optical retardation. In addition, the NZ coefficients of the films were greater than 1 implying that the films were negative biaxial.