Effect of Dopant Structure on Birefringences and Symmetric Tensor Invariants of Lyotropic Nematic Phases

Abstract

In this study, we investigated the effect of the dopant structure on the birefringences and the symmetric tensor invariants of lyotropic discotic nematic (ND), calamitic nematic (NC) and biaxial nematic (NB) phases. Lyotropic host mixture consisted of potassium laurate (KL)/decanol (DeOH)/water. Some dopant molecules were added to this host mixture to obtain quaternary mixtures and to investigate the nematic phase properties by polarizing optical microscopy and laser conoscopy. It was found that the dopant molecules with aromatic ring affect the birefringences and symmetric tensor invariants more efficiently than those with straight alkyl chain.