Complete immiscibility in binary cholesteryl-n-carboxylic acid ester/stearic acid monolayers at the water/air interface

Applying different surface and spreading techniques to form binary monolayers in a different mixing state, the mixing behavior of the three binary systems cholesteryl formiate/stearic acid, cholesteryl acetate/stearic acid, and cholesteryl-n-propionate/stearic acid were investigated and compared.Analyzing the force ()/area (a) isotherms and the equilibrium spreading pressures (^e of the binary monolayers, it can be concluded that the components of the three binary systems do not mix within the whole concentration range. The lipids in the binary monolayers are completely immiscible.