n‐Hexadecyl‐4‐Methylpyridinium Bromide Micellization, Sudan III Solubilization Test, [C ₁₆ ppicoBr]‐SDS Interaction, KBr and NaBr Effects, and Thermodynamics Studies

ABSTRACT The present study aims to report the micellization behaviors and thermodynamics of n‐hexadecyl‐4‐methylpyridinium bromide [C 16 ppicoBr] in aqueous solutions at varied temperatures by using conductivity measurements. The Kraft points were determined to be 30.5 °°C and 32.1 °°C , respectively, for 10 and 50 mM [C 16 ppicoBr] in aqueous solution. Critical micellar concentration (CMC) values were determined to be quite low in the range of 0.695‒0.885 mM at 308.15‒328.15 K. Moreover, the CMC value of [C 16 ppicoBr] in aqueous solution was found to be 0.706 mM at 308.15 K by using the Sudan III solubilization method. Also, in aqueous solutions, the effect of [C 16 ppicoBr] on sodium dodecyl sulfate micellization and the effects of sodium bromide (NaBr) and potassium bromide (KBr) salts on micelle formations of [C 16 ppicoBr] were studied. In mixed micellization systems prepared, the presence of [C 16 ppicoBr] in solution facilitates the micellization of sodium dodecyl sulfate, but not much. NaBr and KBr decreased the CMC value of [C 16 ppicoBr] with their increasing concentrations in aqueous solution. The thermodynamic data showed that micellization of [C 16 ppicoBr] in water solution at varied temperatures is spontaneous, endothermic at 308.15 K, exothermic at 313.15 K, and higher temperatures.