Interactions between cyclodextrins and a mixed cationic cellulose ether: Anionic surfactant gelling system

The intermolecular interactions in aqueous solutions containing polyelectrolytes, surfactants, and cyclodextrins were probed using rheology. The association of surfactant aggregates with the oppositely charged polymer leads to points of physical crosslinking and to a viscosity increase. Cyclodextrins can control this viscosity enhancement by forming inclusion complexes with the hydrophobic moieties of surfactants and thus disrupting the network formed by the surfactants and the polymers. We found the concentration of cyclodextrin required to "deactivate" the surfactant to be approximately double the surfactant concentration. β-CD is more effective than α-CD in reducing the solution viscosity. The molecular recognition abilities of cyclodextrin can be exploited in modifying the solution properties and functionality of polymers.