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Aggregation behavior of unsubstituted copper porphyrazine (CuPaz) on the water surface was studied by analysis of compression curves, Brewster angle microscopy (BAM), and optical spectroscopy. The structure and stability of the CuPaz aqua aggregates in the floating layers are determined by hydration degree that depends on initial surface concentration and surface pressure. Langmuir-Schaefer (LS) films of CuPaz were prepared by deposition of the variously structured floating layers and studied by X-ray scattering technique and optical spectroscopy. Stable and labile structures were detected and compared with the floating CuPaz aqua aggregates. Conditions of formation of the stable four-stacked nanoaggregates in LS films were determined. A model comprising both nucleation of CuPaz on the water surface and structural transformations in the solid films is proposed.

The structure of floating layers of soluble copper tetra-(3-nitro-5-tert-butyl)-phthalocyanine (CuPc*) is studied through surface pressure−area (π−A) isotherms measured at various initial surface concentrations (N 0) of CuPc*. In the gaseous layers, the CuPc* molecules are surrounded by a hydration sphere. Condensation of the layers under compression results in an increase in the tilt angle of the CuPc* molecules relative to the air−water interface. Though it is accompanied by a loss of weakly bound water, an inner part of the hydration sphere sustains compression and enters the condensed layers. Depending on the N 0 and π values, the molecular tilt angle ranges from 30 to 90° indicating the phase states of the β-, α-, and x-types. The different nature of the bilayers formed through compression of the rare monolayers and through spreading of large amounts of CuPc* is stated.

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