SPECTRAL STUDY OF DYE-SURFACTANT INTERACTIONS IN RELATION TO DYE INDICATOR STRUCTURES

Anionic azo dyes with structural variations such as V-acid, p-nitrophe nyl-, p-chlorophenyl-, p-sulphonicphenyl-, p-sulphonic- and m-sulphoni c- salicylic acids have been used to study the structural effects on t he behaviour of anionic and cationic surfactants. The substituents - N O2 and - SO3H, make dyes more anionic and hence the system even with c ationic surfactants behaves as an anionic one promoting micellisation and solubilisation with increasing light intensity. However, with elec tropositive hyperconjugative - CH3 group, anionic character is decreas ed with decrease in absorbance intensity.