Thermodynamic and spectroscopic studies on cationic surfactant tetradecyltrimethylammonium bromide in aqueous solution of trisubstituted ionic liquid 1, 2-dimethyl-3-octylimidazolium chloride at different temperatures

Abstract

In this work, the effects on micellar behavior of long chain cationic surfactant tetradecyltrimethylammonium bromide (TTAB) upon the addition of trisubstituted ionic liquid (IL), 1, 2-dimethyl-3-octylimidazolium chloride [odmim][Cl] at temperatures, 298.15–318.15 K has been studied. Different techniques such as conductance, surface tension, fluorescence and ¹H NMR have been employed to understand the interactional mechanisms. The values of critical micelle concentration (cmc) and various thermodynamic parameters have been calculated from conductivity measurements. The surface parameters like effectiveness of decrease in surface tension (Π_cmc), minimum surface area occupied per surfactant monomer (A_min), maximum surface excess concentration (Γ_max), and adsorption efficiency (pC₂₀) have been evaluated by surface tension measurements. Micellar aggregation number (N_agg) has been determined by quenching of pyrene. Further to understand interactions in post micellar region, ¹H NMR measurements have been performed. It has been observed that the lipophilicity of interacting ion modified the thermodynamic and aggregation properties of TTAB.

Graphical abstract

Keywords:

• Trisubstituted ionic liquid
• Tetradecyltrimethylammonium bromide
• micellization
• conductance
• ¹H NMR

Additional information

Funding

Council of Scientific and Industrial Research (CSIR), Government of India.