Thermodynamics and in-situ absorption of Langmuir monolayers of selected copper phthalocyanine substituted with different peripheral groups

The paper deals with thermodynamic and spectroscopic characterization of Langmuir layers of phthalocyanines substituted with different peripheral groups: copper(II) 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine, copper(II) 2,3,9,10,16,17,23,24-octakis(octyloxy)-29H,31H-phthalocyanine, copper(II) tetrakis(4-cumylphenoxy)phthalocyanine. The isotherms, compressibility and stability of the Langmuir layers are investigated. Molecular arrangement of the molecular skeleton on water substrate is also evaluated. The essential influence of the substituents attached to the phthalocyanine macroring on dye thermodynamic properties is shown. The in-situ absorption of the phthalocyanine monolayers and electronic absorption spectra of dye solution in chloroform support existence of aggregates which architecture depends on the dye molecular structure.