Enhanced chromonic stacking assisted by a hydrogel network

Abstract

We report that the stacking order in lyotropic chromonic liquid crystal (LCLC) Sunset Yellow FCF (SSY) is enhanced when incorporated into a cationic hydrogel via the ionic bonds. The chromonic-incorporated gel is initially opaque but transparent and shows a birefringence at high temperatures. The stacking correlation length at room temperature (≈25 °C) is as large as 5.97 nm, corresponding to about 18 molecules in a single stack, and the stacking energy is found to be 7.96 k B T. Both values are larger than those in a normal SSY solution with the respective concentration (≈1 M).