Variation of Electric Conductivity of Sodium Dodecyl Sulfate with the Complex Formation between lt and Poly(vinylpyrrolidone) or Poly(vinyl alcohol)

Abstract

Interaction between sodium dodecyl sulfate (SDS) and poly(vinylpyrrolidone)(PVP) or poly (vinyl alcohol) (PVA) was studied by the measurement of conductivity at 30C. Equivalent conductivity, Aobs, of SDS decreased with increasing concentration of polymer, cp, in the case of low concentration of total SDS, cst. On the other hand, in the case of high concentration of this, cst(>CMC), Aobs, increased by the addition of PVP. These relations are shown in Figs.1 and 2.
It was found that the equivalent conductivity of PVA-SDS complex was of the same magnitude as that of SDS micelle (29 ohm^-1cm²eq.^-1), but that of PVP-SDS complex was slightly larger than that of SDS micelle, as show in Fig.6.
Assuming the complex to be a polyelectrolyte, and free SDS in the solution to be an added salt, it was found that the equivalent conductivity per bound SDS of the complex would behave quite similarly as that of a polyelectrelyte in a solution of a simple electrolyte, as shown in Figs.6 and 7. lt was, therefore, concluded that the complex could be considered as a polyelectrolyte.