SIZE OF MICELLES OF 1-DODECYLPYRIDINIUM CHLORIDE IN AQUEOUS NACL SOLUTIONS

Static light scattering has been measured on aqueous NaCl solutions of 1-dodecylpyridinium chloride over the NaCl concentrations from 0 to 4.00 M at 25-degrees-C, and the micelle molecular weight has been estimated by means of the Debye equation. In aqueous solution the molecular weight is as small as 5280, corresponding to the aggregation number, 18.6. With increasing NaCl concentration up to 0.05 M the molecular weight increases sharply, reaching 12350. The small micelles would not be so compact as the common spherical micelles but would be porous except for their core. With increasing NaCl concentration beyond 0.05 M the micelle molecular weight increases only gradually, similar to growth of the common spherical micelles, and reaches 20410 in 4.00 M NaCl.