J. Toullec et S. Couderc, CONDUCTIVITY OF IONIC SURFACTANT SOLUTION S - EVIDENCE FOR CHANGES INTHE DEGREE OF IONIC DISSOCIATION OF MICELLES WITH SURFACTANT CONCENTRATION, Comptes rendus de l'Academie des sciences. Serie II. Mecanique, physique, chimie, astronomie, 324(12), 1997, pp. 773-780
Contrary to what is generally accepted, the conductivity data (K) for
aqueous solutions of ionic surfactants are shown to be consistent with
a significant decrease in the degree (alpha) of micelle ionic dissoci
ation when the surfactant concentration increases. The linear variatio
ns of K above the critical micelle concentration (cmc) do not stem fro
m a constancy of alpha, but from compensatory effects on K. Conductivi
ty data for dodecyltrimethylammonium bromide (DTAB) are examined to il
lustrate this point.