Investigation of the Ability of Micelle Formation of Two Ionic Surfactants in Presence of Metronidazole Drug.

This document is concerning with the main driving factor for the formation of micelle, which may be introducing more evidence to promote the past works about this phenomenon. The variety of functional groups in the metronidazole (Met) drug as slightly soluble in water may give a good object for understanding the micellization when existed as an additive substance for determining the critical micelle concentration (CMC). Two ionic surfactants including anionic sodium dodecyl sulphate (SDS) and cationic cetyltrimethylammonium bromide (CTAB) more explored at different temperatures using electrical conductivity method. The results indicated that there is a positive effect on CMC of SDS as the CMC decreased with increasing Met concentration which then made reduction in ionization degree (). Contrary, the CMC of CTAB was increased with increasing the amount of Met as working against the formation of micelle. The standard thermodynamics functions of micellization including enthalpy H, entropy S, and Gibbs free energy G were evaluated. It was noted that the sign of enthalpy and Gibbs free energy of micellization for two surfactants are negative, but the sign is positive of entropy for aggregation process of surfactants as there is no change due to presence of met. Intuitively, the CMCs of SDS and CTAB are directly proportional with temperature in presence and absence of Met due to the negative effect on the intermolecular force between molecules.