Studies on the Light Scattering of the Complex between Poly(vinylpyrrolidone) and Sodium Dodecyl Sulfate in Aqueous Solution

Abstract

The reduced intensity of the scattered light, R0, by aqueous solution of poly (vinylpyrrolidone) (PVP) mixed with sodium dodecyl sulfate (SDS) was measured in various concentrations of PVP and SDS. Outer solution at the membrane equilibrium was used to dilute the inner solution of PVP-SDS complex in order to keep the chemical potential of SDS or the concen- tration of free SDS (c. ) constant. The lines in the Zimm plot which shows the relationship between the concentration of PVPSDS complex and Kccomp-b.1 Re at a constant scattering angle ( 0 ), where K is a constant, are not straight but curved, as shown in Figs.2-5. It is concluded that the virial coefficients in the higher orders are responsible for these phenomena. The relationship between these virial coefficients and the concentration of free SDS is shown in Fig.7'. It is concluded that the dependence of these virial coefficients on c. f can be explained by taking into account both the amount of SDS bound to PVP and the density of electric charge on the complex, because this complex is considered as a kind of polyelectrolyte.