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2774352 
Journal Article 
Aggregation and adsorption behavior of cetylpyridinium chloride in aqueous sodium salicylate and sodium benzoate solutions 
Mukhim, T; Dey, J; Das, S; Ismail, K 
2010 
Yes 
Journal of Colloid and Interface Science
ISSN: 0021-9797
EISSN: 1095-7103 
350 
2 
511-515 
English 
20673910 
The critical micelle concentration (cmc) values of cetylpyridinium chloride (CPC) were determined in the presence of salicylate and benzoate ions in the less explored concentration region where viscosity is Newtonian. The cmc of CPC decreased from 9 x 10(-4) to 7 x 10(-7) and 3 x 10(-6) mol kg(-1) by adding about 0.3 mol kg(-1) of salicylate and benzoate, respectively. The ortho hydroxyl group in salicylate thus has a remarkable influence on the micellization of CPC and the extent of this favorable effect is found to be about 3.5 kJ mol(-1). The Corrin-Harkins equation was modified to explain the variation of cmc with electrolyte concentration in the presence of mixed counterions. The slope of the equation does not provide the value of the total counterion binding constant (beta), but gives us information about the lower limit to the value of beta, which is found to be 0.66. Addition of salicylate and benzoate increases the counterion binding to CPC micelles compared to that in the presence of chloride alone. An adsorption isotherm was derived to estimate the surface excess of CPC in the presence of mixed counterions.