Interactions of a hydrophobically modified cationic cellulose ether derivative with amphiphiles of like charge in an aqueous environment

The interactions of a hydroxyethylcellulose ether derivative (Quatrisoft® LM200), substituted with cationic, hydrophobic side chains, with cationic surfactants, differing in the composition of the head group, were examined by conductivity, fluorescence, and dye solubilization techniques. The surfactants investigated included alkyl pyridinium chloride salts, alkyl trimethylammonium bromide salts, the alkyl dimethylammonium bromide salts, and alkyl ammonium bromide salts. All surfactants investigated interacted with the LM200 molecules to form micelle-like aggregates prior to the critical micellar concentrations of the surfactants. Hydrophobic interactions and the ability to form hydrogen bonds play a role in the polymer¯surfactant association. This associative behavior was shown to depend significantly on both the polymer and surfactant concentrations. In addition, the polymer molecules also interact with each other in solution. The resulting hydrophobic polymer microdomains were detected using fluorescence probe studies.