Hysteresis of Isotherms of Mixed Monolayers of N-Octadecyl-N′-phenylthiourea and Stearic Acid at Air/Water Interface
Area per molecule assuming the monolayer comprises 1 : 1 complex and excess SA versus mole fraction of SA in the spreading mixture. Any excess OPT is assumed removed from the monolayer. The solid line indicates constant area/molecule. At low mole fractions of SA deviation sets in from the constant value obtained at mole fractions of SA 0.4 or higher.