Effect of spacer length on the micellization and interfacial behavior of mixed alkanediyl-α,ω-bis(dimethylcetylammonium bromide) Gemini homologues

The interfacial and micellization properties of binary and ternary mixtures of Gemini homologues, viz., tetramethylene-1,4-bis(N-hexadecyl-N,N-dimethylammonium bromide), pentamethylene-1,5-bis(N-hexadecyl-N,N-dimethylammonium bromide), and hexamethylene-1,6-bis(N-hexadecyl-N,N-dimethylammonium bromide), with various compositions were investigated at 25 degrees C using conductometric and tensiometric measurements. The micellar and adsorption characteristics like composition, activity coefficients, mutual interaction parameter, minimum area per molecule, free energy of micellization and adsorption have been evaluated and compared. The ideality/nonideality of the mixed micelles were tested in light of Clint, Rubingh, and Rubingh-Holland approaches. The mixed systems were found to undergo synergistic interaction, more so in mixed monolayer than in mixed micelle formation, and the micellar and interfacial properties were found to depend on the selection of surfactant pairing. (C) 2009 Elsevier Inc. All rights reserved.