Viscosity and Density Studies on the Second CMC of the Aqueous Solution of Dodecyl Pyridinium Chloride

[摘要] According to the viscosity and density studies of an aqueous solution of dodecyl pyridinium chloride (DPC) it was shown that the 2nd critical micelle concentration (2nd cmc) existed in the solution in addition to the 1st cmc. The volume fraction ¥÷m of the hydrated micelle was calculated by using the following equation: ¥çrm = 1 + 2.5¥÷m + 14.1¥÷m2 It has been found that the increment of ¥÷m in the ¥÷m vs. Cm curve decreased at near the 2nd cmc. And the partial specific volume (v) of DPC obtained from the density measurement also decreased rapidly at near the 2nd cmc and remains constant value above the 2nd cmc. This may be attributed to a change in the micelle structure at the 2nd cmc caused by a variation in the type of aggregation and by a decrease in the counterion binding by the micelle.

[学科分类] 化学（综合）