Solubilization of a Water-Insoluble Dye in Aqueous Sodium Halide Solutions of Dodecylpyridinium Halides: Effects of Counterion Species of Ionic Micelles

✍ Scribed by Shoichi Ikeda; Yasuhiro Maruyama

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 270 KB
• Volume: 166
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1994.1263

✦ Synopsis

Solubilization of Sudan Red B in aqueous micellar solutions of dodecylpyridinium chloride (DPC) in the presence of (\mathrm{NaCl}) from 0 to (4.00 \mathrm{M}) and of dodecylpyridinium bromide (DPB) in the presence of (\mathrm{NaBr}) from 0 to (6.00 \mathrm{M}) has been examined to investigate the effects of added salt, i.e., micelle size, shape, and structure. The DPC micelles have solubilization power, (2.08 \times) (10^{-3} \mathrm{~mol}) per mole micellar DPC, over the range of 0 to (4.00 \mathrm{M}) (\mathrm{NaCl}). The constant solubilization power of DPC, independent of its micelle species, either porous at lower (\mathrm{NaCl}) concentrations or spherical at higher (\mathrm{NaCl}) concentrations, suggests that the solubilization locus of a spherical micelle locates near its polar or outer parts. The DPB micelles have solubilization power, (2.26 \times 10^{-3} \mathrm{~mol}) per mole micellar DPB, in the range from 0 to (3.12 \mathrm{M} \mathrm{NaBr}), where the formation of spherical micelles and their mutual repulsive or no mutual interaction in solution has been confirmed by light-scattering measurements. At higher (\mathrm{NaBr}) concentrations where spherical micelles formed, the critical micelle concentrations are subject to mutual attractive interaction; at finite micelle concentrations, the solubilization power increases with increasing (\mathrm{NaBr}) concentration, in such a way that it behaves characteristically as if rodlike micelles are formed. (1) 1994 Academic Press. Inc.