Interaction between a bio-tolerable amino-acid based amphiphile (N-dodecanoylsarcosinate, SDDS) and modified cationic polymers, hydroxyethylcelluloses (JR 400, and LM 200) in isopropanol-water medium

Abstract

Interaction between the eco-friendly amino-acid based anionic amphiphile (N-dodecanoylsarcosinate, SDDS) and the cationic polymers, hydroxyethylcelluloses (JR400 and LM200) in isopropanol-water (IP/W) medium has been studied employing different techniques. Formation of SDDS micelles, and their binding interaction with the polymers by way of charge and hydrophobic interactions have been investigated, and physicochemical corroboration of the results has been looked into. Interfacial and bulk behaviors of SDDS in the mixed IP/W medium have been examined; the information on the micelle type, shape and counter-ion binding as well as the related thermodynamic parameters have been estimated. The solvent property (Gordon Parameter), and the shape of the micelles (in terms of the Israelachvili’s “packing parameter”(P)) have been also estimated in the mixed solvent system. The critical aggregation concentration of the polymer induced micelles (CAC), their complete binding (CS) to the polymers forming necklace-bead like configurations, and finally forming the extended free micelles of the surfactant (CMCe) in the IP/W medium have been evaluated. The formation of coacervate phase in the system, and its dissolution during the interaction process has been noted, and supported from the turbidity measurements. The overall thermodynamics of the interaction process have been estimated from isothermal titration calorimetry (ITC) measurements. A comparison of parities among the results of different methods (tensiometry, conductometry, turbidimetry and calorimetry) has been made. Possible utility values of the interacted products in pharmacy, medicine, nano- science, etc. have been indicated.