Unraveling the micellization behavior and thermodynamic characteristics of imidazolium-based ionic liquid in presence of vitamins thiamine hydrochloride and ascorbic acid

Abstract

The micellization properties of long alkyl chain imidazolium-based ionic liquid 1-dodecyl-3-methylimidazolium bromide [C12mim] [Br] in aqueous solution and presence of vitamin B1 (thiamine hydrochloride) and vitamin C (ascorbic acid) has been systematically investigated employing conductometric titrations, FT-IR spectroscopy, UV-Visible spectrophotometer, and fluorescence spectroscopy. The CMC value of [C12 mim] [Br] is evaluated from conductivity measurements at three different working temperatures (298.15 K, 308.15 K, and 318.15 K) in absence and presence of different concentrations (0.1, 0.2 and 0.3 wt%) of vitamins (thiamine hydrochloride and ascorbic acid). There is a decrease in the value of critical micelle concentration with increasing vitamin concentration and with increasing temperature, the CMC value also increases. The results obtained were due to the adsorption of vitamins on the micellar surface and the disruption of water molecules. The various micellization parameters such as Gibbs free energy of micellization (ΔGm0), enthalpy (ΔHm0), and entropy of the micellization processΔSm0have been calculated. The negative ΔGm0and ΔHm0specify the feasibility and exothermic nature of the micellization process. Further UV-Visible and fluorescence spectroscopy are the complementary techniques to validate the CMC values obtained from conductivity measurements which are found to be very close to that obtained via conductivity study. FT-IR spectroscopy determines structural changes at: below CMC, at CMC, and above CMC. The aim of this work is to find the depth knowledge about the interaction between vitamins and surface active ionic liquids and the use of these ionic liquids in target drug delivery, biomedical science as well as bio-industries