Polyvinylpyrrolidone-sodium dodecylsulfate complex is a family of pseudo-polyanions with different charge densities: Evidence from capillary electrophoresis, capillary viscosimetry and conductometry

Abstract

Accordance with the previously supposed polyelectrolyte-like behaviour of neutral polymer-anionic surfactant complexes, direct evidence for the formation of the pseudo-polyanions in polyvinylpyrrolidone (PVP)-sodium dodecylsulfate (SDS) solution is put forward in this paper by capillary electrophoresis (CE) experiments in assistance with capillary viscosimetry and conductometry. The contradictory phenomena of the absolute value of relative electrophoretic mobility (re) increasing while the ionization degree (α) decreasing with the increasing specific clusterization [Г] in aqueous PVP-SDS solution are explained by the finding that the PVP-SDS complex is eventually a family of PVP-SDS pseudo-polyanions with different charge densities. And it is found countercations playing an important role in the formation of the PVP-SDS pseudo-polyanions in virtue of bridge effect.