SOLUBILIZATION OF DYE IN LAMELLAR LIQUID-CRYSTAL OF SYSTEM IGEPAL CO-610 AND H2O

The solubilization and spectrum characteristics of a dye mixture, More fast Red 101, in the lamellar liquid crystal (LLC) of the system Igepa l CO-610 and H2O were studied by measurements of phase behavior, low a ngle X-ray diffraction, UV and visible spectrum. Pure dye molecules, N AHPA, were located in the hydrocarbon chain part of the LLC bilayer of the solvents for the formulated dye. Of the solvents, n-propanol was evenly distributed between all parts of the liquid crystal while the b is(2-ethylhexyl)amine was localized to the space between the mirroring terminal methyl groups of the layered structure. In this manner the i nfluence of the different components was compensated and the net resul t of the added dye was no effect on the interlayer spacing of the lame llar liquid crystal. The UV spectrum of the dye showed an interesting feature. After addition of water to the solution of dye in the relativ ely nonpolar surfactant the change in the dye spectrum showed a less p olar environment of the dye in spite of the increased polarity. The ex planation is found in the ordered structure of the lamellar liquid cry stal; addition of water caused a transfer of the dye from the polar pa rt of the surfactant to the non-polar hydrocarbon chains.