Effect of aromatic amino acids on the surface properties of 1-dodecyl-3-(4-(3-dodecylimidazolidin-1-yl)butyl)imidazolidine bromide gemini surfactant

ABSTRACT

Herein, we have studied the micellization of imidazolium-based ionic liquid type gemini surfactant ([C₁₂-4-C₁₂im]Br₂) in the absence and presence of aromatic amino acids by conductivity and surface tension measurements at different temperatures (i.e., 298, 308, and 318 K). Various interfacial parameters, that is, Gibbs surface excess (Γ_max), minimum head group area at air/water interface (A_min), and thermodynamic parameters, that is, free energy of micellization/adsorption (), the standard entropy of micellization/adsorption (), and the standard enthalpy of micellization/adsorption () were evaluated for all the systems. The standard entropy of adsorption () was found higher than the standard entropy of micellization () for all the systems at all temperatures. The results also showed that the micellization of [C₁₂-4-C₁₂im]Br₂ depends on the nature of amino acids as well as temperature. The CMC of [C₁₂-4-C₁₂im]Br₂ in the absence and presence of amino acids at different temperature decreases with the increase of temperature.

GRAPHICAL ABSTRACT

KEYWORDS:

• Amino acid
• CMC
• hydrophobic interactions
• micellization

Acknowledgments

Dr. Rajan Patel is thankful to Science and Engineering Research Board (SERB), New Delhi, India, for providing research grant with Sanction Order No. (SR/S1/PC-19/2011) and SB/EMEQ-097/2013). Dr. Abbul Bashar Khan is thankful to the Science and Engineering Research Board, New Delhi, India, for providing a research grant (SB/FT/CS-031/2013). Amit Kumar is grateful to Science and Engineering Research Board (SERB), New Delhi (Ref. CS/097/2013 and letter no. SB/FT/CS-100/2013) and Centre for Nano and Material Sciences, Jain University, Bangalore, India for providing financial support and the necessary infrastructure. Authors also thank DST for providing the FIST grant with Sanction Order No. (SR/FIST/LS-541/2012).