Aggregation of Ionic Surfactants and Hydrophobically Modified Cellulose Ethers Conference Paper uri icon

abstract

  • Ionic surfactants tend to aggregate in the presence of polymers such as methyl-o-cellulose at a critical surfactant aggregation concentration (CAC). This concentration is usually much smaller than the critical micelle concentration (CMC) observed in the absence of polymer. A recent scaling theory predicted that the CAC should be associated with a collapse of the polymer chain [H. Diamant and D. Andelman, Macromolecules 2000, 33, 8050]. In this work we report on the study of SDS association with methyl-o-cellulose (MOC). We find that the MOC molecules undergo partial chain collapse at the CAC. We also confirm the theoretical prediction that the ratio of CAC/CMC is constant for different temperatures, surfactants and salt concentrations. At surfactant concentrations above CAC chain dimensions increase due to electrostatic repulsions. At yet higher concentrations free surfactant molecules screen …

publication date

  • January 1, 2003