Anisotropic Structures in Aqueous Solutions of Aggregated Pseudoisocyanine Dyes

摘要: On increasing concentration in highly diluted aqueous solutions of pseudoisocyanine dyes an intensive absorption band extremely small half-width (Scheibe band) occurs which is attributed to the formation dye aggregates or J-aggregates). By polarizing microscopy it shown that diethylchloride at low temperatures and concentrations c > 0.2wt% become birefringent exhibit a Schlieren texture characteristic for nematic liquid crystals. Above certain clearing temperature T C solution becomes optically isotropic during discontinuous phase transition as by DSC. The Scheibe vanishes some degrees above . behaviour displayed terms T-c diagram. aggregation numbers have been determined spectroscopically about 40 50 only slightly below Obviously, long-range orientational order even high dilution typically lyotropic crystal. diagram indicates on first before will be thermically decomposed.