Mixed micellization and interfacial properties of hexanediyl-1,6-bis(dimethylcetylammonium bromide) in the presence of amines

Riyaj Mohammad^a, Iqrar Ahmad Khan ^b, Kabir-ud-Din^b

^a Department of Chemistry, Invertis University, Bareilly-243123, U.P., India;  ^b Department of Chemistry, Aligarh Muslim University, Aligarh-202002,U.P., India

Email: riyaz138@gmail.com

Abstract:

Mixed micellization and interfacial properties of cationic gemini surfactant hexanediyl-1,6-bis(dimethylcetylammonium bromide) (16-6-16) have been studied in the presence and absence of various primary linear alkylamines using tensiometry at 303 K. A synergistic effect was observed in all instances that were found to be correlated with chain length. It was found that the CMC of 16-6-16 decreased with increasing amine concentrations and the extent of effect followed the sequence: octylamine (C₈NH₂)  >  heptylamine  (C₇NH₂)  >  hexylamine (C₆NH₂)  >  pentylamine (C₅NH₂)  > butylamine (C₄NH₂). Data on critical micelle concentration (CMC), the surface properties C₂₀   (the surfactant concentration required to reduce the surface tension by 20 mN/m), Γ_max (maximum surface excess), A_min (minimum surface area per molecule) evaluated from  the surface tension  versus surfactant  concentration  plot,  the  interaction  parameters  (for  mixed  monolayer  formation  at  the aqueous solution/air interface), and (for mixed micelle formation in aqueous medium) are reported. A synergistic interaction was observed both in the micelle as well as at interface, as  evident from interaction parameters. Theoretical models of Clint, Rubingh and Rosen were used  to  explain and compare the results.

Keywords: Alkylamines, gemini surfactant, mixed micelle, synergism