Abstract
The study of the interaction between aspartic acid (Asp) and cetyltrimethylammonium bromide (CTAB) reveals important information about surfactant organization, surface tension, critical micelle concentration (CMC), and surface pressure. Because of enhanced surfactant solubility brought about by electrostatic interactions, Asp’s ionization lowers CTAB’s CMC. The maximal surface excess concentration falls with increasing Asp concentra- tion, suggesting competition for surface adsorption. The minimum occupied area per surfactant molecule in- creases at the same time, indicating changed surfactant activity at the interface between air and water. Higher CTAB concentrations are associated with a decrease in surface tension, which suggests that when Asp concen- tration rises, micelle formation would be promoted. Saturation effects, on the other hand, happen at high Asp concentrations and interfere with micelle formation. These tendencies are supported by surface pressure mea- surements, highlighting the signi cance of ionic interactions in micelle behavior. Moreover, surfactant structuring is impacted by the packing parameter decreasing as Asp concentration in- creases. The changing balance between hydrophilic and hydrophobic interactions within the CTAB/Asp micellar complexes is further explained by variations in degree of counterion dissociation of micelles (α) values. The complex dynamics of ionic interactions and their impact on surfactant behavior in CTAB/Asp systems are highlighted by these studies.