Interaction of cationic hydroxyethylcellulose (JR400) and cationic hydrophobically modified hydroxyethylcellulose (LM200) with the amino-acid based anionic amphiphile Sodium N-Dodecanoyl Sarcosinate (SDDS) in aqueous medium

Interaction of an ionic amphiphile with an oppositely charged polyelectrolyte may dramatically alter the physicochemistry of the polymer in solution. Exploration of the macro and microscopic details of such processes is a topic of contemporary interest. In this study, results of interaction of the anionic amphiphile, Sodium N-Dodecanoyl Sarcosinate (SDDS) with the cationic hydroxyethylcellulose, JR400 and hydrophobically modified cationic hydroxyethylcellulose, LM400 at the air/water interface and in the bulk over a fair range of concentration in the absence and presence of salt are presented. At a very low concentration, SDDS monomers interact with the polymer; above the critical aggregation concentration (CAC), small micelle like aggregates form complexes with the polymer. The complex, thereafter, self-associates to form a turbid coacervate phase. At increased [SDDS], the turbidity decreases by way of disintegration of the coacervates, and the solution becomes clear. The salt, NaCl affects the SDDS–polymer interaction. The amphiphile interaction with mixed JR400 and LM200 also produces characteristic interfacial and bulk features. Different physical methods are employed to probe the interaction process and an attempt for correlation of the results has been made.