BINDING OF SODIUM DECYL SULFATE TO A CATIONIC POLYMER.

Abstract

Interaction between sodium decyl sulfate and a cationic copolymer of dimethyldiallyammonium chloride and sulfur dioxide was studied by a potentiometric method utilizing a surfactant-selective electrode. Binding occurs suddenly and is completed in a very narrow range of equilibrium concentration, indicating the strongly cooperative nature of the binding process. The characteristic concentration at which binding starts is about two orders of magnitude smaller than the critical micelle concentration. The cooperativeness parameters as estimated by a nearest neighbor interaction model remains almost constant on increasing sodium chloride concentration, affinity for an isolated binding site decreasing.