Impact of deep eutectic solvents on cetyltrimethylammonium bromide: a comparative study

Study the micellization characteristics of cetyltrimethylammonium bromide (CTAB) in three deep eutectic solvents (DESs)—L-tyrosine (DES-1), L-glutamine (DES-2), and L-aspartic acid (DES-3)—by using surface tension, viscosity, fluorescence UV–vis spectrophotometry, and FTIR spectroscopy. Prepared DESs are made by mixing choline chloride with three different amino acids in 1:2 M. Study the DESs Effect on the critical micellar concentration (CMC) of CTAB. When increasing the weight percentage of DESs, the CMC value of the CTAB falls. Calculate the CMC and interfacial parameters such as surface tension at CMC (γcmc), the minimum area per molecule (Amin), the minimum surface activity (πcmc), the efficiency of adsorption (PC20), critical packing parameter (CPP), and the maximum surface excess concentration (Γmax). A decrease in the Γmax and Amin and an increase in the micellization systems when the weight present of amino acid-based DESs increases. FTIR spectroscopy was used to examine the self-assembly interactions between the DESs and surfactant (DESs:CTAB) that led to modifications in their structure and function. Furthermore, it is important to note that the micellization process for three AAs based on DESs with CTAB in the following order (with 5 wt% DESs) DES-3 > DES-2 > DES-1 and (with 10 wt% DESs) DES-3 > DES-1 > DES-2. Besides surface tension investigations, micellization of CTAB with the three amino acid-based DESs was also validated using fluorescence and UV–vis spectrophotometry, which indicated a consistent decrease in CMC with an increase in DES concentration. The measurements of viscosity showed that there was an increase in structural arrangement and intermolecular interactions in the CTAB:DES systems, which led to the improvement of the micelle formation. Combined, these methods show that DESs greatly support the process of micellization and alter the physicochemical behavior of CTAB.