Synthesis and Interfacial Properties of Novel Benzimidazolium Based Gemini Surfactants and Their Binding with Crocin

Abstract

The novel cationic benzimidazolium based gemini surfactants BG6 and BG12 with dissimilar alkyl chain lengths were synthesized and characterized. Their surface-active parameters viz, critical micelle concentration (cmc), minimum area per molecule (Amin), maximum surface excess concentration (max), packing parameter (P), etc., were evaluated by utilizing the surface tension. The observed cmc of BG12 is lower as compared to BG6, suggesting that BG12 has more surface activity than BG6. The standard Gibbs free energy of micellization (ΔG°m) comes out to be negative, which suggests that the micellization process is spontaneous and becomes more favorable with an increase of the temperature. Besides this, the effective diffusion coefficients (D) at shorter times as well as for longer times have been evaluated by employing the Ward and Tordai equation. The UV-visible and fluorescence spectroscopic techniques were employed to determine the binding constant of BG8 and BG10 with crocin. Also, the cyclic voltammetry and differential pulse voltammetry techniques were used to study various electrochemical parameters of crocin in the presence of BG surfactants.