Polarization efficiency enhancement of anisotropic films cast from yellow lyotropic chromonic liquid crystal using its coupled core structure

Abstract

Polarizing films were made by drying lyotropic chromonic liquid crystals (LCLCs) aqueous solutions that have been aligned by shearing. To improve the polarizing efficiency (measured at 400nm) of a film prepared from a yellow LCLC, a biaryl yellow compound was synthesized by coupling two of the yellow dye chromophores together via C–C a bond. The polarization efficiency of a film cast from a yellow LCLC solution was increased from 78.2% to 89.7% by mixing yellow LCLC with a little amount of biaryl yellow compound (yellow LCLC:biaryl yellow=99:1). Broad-spectrum polarizing films made from a LCLCs mixture consisting of yellow, red, violet and blue LCLCs was least effective in the yellow region, but the addition of this compound increases the polarization efficiency at 400nm from 80.8% to 90.1%.