Spectral Studies of Eriochrome Black T in Cationic Surfactants

摘要

The critical micelle concentration (CMC) for a series of cationic surfactants N-Alkyltrimethylammonium i.e. (C_(n)TAC, n=12, 14, 16, 18) have been determined by electrical conductivity and surface tension methods. The interaction of anionic dye Eriochrome Black T (EBT) with cetyl-trimethylammonium chloride and cetylpyridinium chloride (CPC) has been investigated spectrophotometrically. The binding constant ( K _(b)) and the surface excess (Γ) were calculated. The results show that with increasing the surfactants alkyl chain lengths, CMC and minimum area ( A_(min) ) decreases, while the surface excess concentrations increase. It has been found that the binding constant of CPC is double - fold that than of the binding constant of cetyl-trimethylammonium chloride (C_(16)TAC).