engleski

Characterization of micellar systems by the conductivity method; Sodium salt of perfluoropolyether carboxylic acid

A new method for the interpretation of the conductivity of ionic surfactants is proposed. The model considers the contribution of ions and of charged micelles, and is based on the approximation of constant concentration of surfactant chains above the critical micellization concentration (CMC), and on the equilibrium constant of counterion binding to the micelles (K). These two parameters evaluated for aqueous solutions of sodium salt of perfluoropolyether carboxylic aqcid are as follows: K = 35 800 dm^3mol^-1 ; CMC = 1.19 x 10^-3 mol dm^-3. The third quantity obtained by this procedure is rthe product of the aggregation number (N) and the size parameter (f = e2 L/ 6π η r): Nf = 76.5 cm^2 mol^-1.

conductivity ; micelles ; counterion binding ; perfluorinated surfactants

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