Mixed monolayer properties of bile acids spread on the concentrated sodium chloride solution

Abstract

The surface pressure (π) and the surface potential (Δ V)-area ( A) isotherms for mixed monolayers of cholic acid (CA)/β-muricholic acid (β-MCA) on 5 M sodium chloride solution were measured at various compositions by the Langmuir method and the ionizing electrode method. The results for the mixed monolayers were analyzed in terms of the additivity rule. The showed that cholic acid forms an ideal two-dimensional solution when mixed with β-muricholic acid. From the mean molecular area and surface dipole moment, the orientation of bile acids in the monolayer state was estimated.