Miscibility and Molecular Orientation of Carbazole in Mixed Langmuir and Langmuir--Blodgett Films

We report the miscibility and molecular orientation of carbazole (CA) molecules in the mixed Langmuir and Langmuir--Blodgett (LB) films of CA
in polymethyl methacrylate (PMMA) and stearic acid (SA) matrices. The π-A isotherm confirms the formation of stable Langmuir films of CA mixed with either PMMA or SA at air--water interface. Characteristics of area per molecule versus molefraction and collapse pressure versus molefraction reveal complete demixing of CA and the matrix PMMA/SA molecules in the mixed films. Absorption spectroscopy certainly confirms the fact that CA molecules have preferred orientation on the substrate of the LB films.