Composition triggered Aggregation/Solubilization behaviour of mixed counter charged gemini Surfactants: A Multi-technique investigations

Abstract

• Fluorescence parameters can be used to detect the interaction between counter charged geminis. • Composition variation modulates the apparent dielectric constant of the mixed micelle. • Mixing can tune micelles of different architectures which further depend on spacer nature. • Zeta (ζ) values show charge reversal during composition variation. • A correlation has been proposed for the dependence of MSR on the micellar environment- morphology- composition. Aqueous association behaviour of counter charged gemini surfactants has been studied by fluorometry, dynamic light scattering (DLS), Zeta(ζ)-potential and SANS measurements at 303 K. For the purpose, P, P'-1,4-butanedieyl, P, P'-didodecylester, disodium salt, anionic surfactant(12–4-12A) and cationic gemini surfactants: Butanediyl-1,4-bis (N, N-dimethyl-N-tetradecyl-ammonium) dibromide (14–4–14); Ethane-1,2-diyl bis (N, N-dimethyl-N-tetradecyl-ammonium acetoxy) dichloride (14-Eg-14) and (D-isosorbate-1,4-diyl bis (N, N-dimethyl-N-tetradecylammonium acetoxy) dichloride (14-Isb-14) were mixed for varying mole fraction range ( x = 0–1). Fluorescence data using pyrene as a probe are used to obtain CMC values which were theoretically treated using regular solution theories. It has been observed that mixing causes non spherical micelles and even vesicle formation was observed in one of the combinations (12–4-12A + 14–4–14) at x = 0.4. Various compositions are used to solubilize polycyclic aromatic hydrocarbon (pyrene, anthracene and phenanthrene) in order to have an idea of solubility enhancement efficacy. Micellar morphology/environment has been used to draw a correlation between apparent dielectric constant (D exp ) - composition - solubilization potential. Findings can be used for loading various hydrophobic materials in an appropriate amphiphilic mixture for various applications such as dye solubilization, drug solubilization, drug delivery or drug targeting.