Atypical Film-Forming Behavior of Soluble Tetra-3-Nitro-Substituted Copper Phthalocyanine

Thin films of metal phthalocyanines (MPc) are known to exhibit excellent physical properties but poorly controlled morphologies. Therefore, the present work seeks to understand the film growth mechanism of a model compound for potentially usable MPc, specifically, copper tetra(3-nitro-5-tert-butyl)phthalocyanine (CuPc*). The Langmuir-Schaefer (LS) technique was applied to prepare a series of CuPc* films under different processing conditions. The film growth was examined by Brewster angle microscopy (BAM) on the water surface and small-angle X-ray scattering (SAXS) from the solid films. Neutron reflectometry (NR) measurements of the water uptake into the films and computer simulation of hydrated CuPc* were performed to substantiate an idea of colloidal MPc-water aggregates as nanoscale precursors of smooth solid films. This idea appears fruitful in terms of materials chemistry.