Self-assembly and properties of phthalocyanine and polyelectrolytes onto melamine resin particles

Abstract

Hollow capsules have been prepared by electrostatic layer-by-layer self-assembly of tetrasulfophthalocyanine iron [Fe(PcS₄)] in alternation with poly(diallyldimethylammonium chloride) (PDDA) onto the precursor shells with well-defined internal volumes. The resultant linear deposition process was monitored by UV/Vis absorption spectra, microelectrophoresis, and scanning force microscopy (SFM). The formation of intact spherical capsules was verified by confocal laser scanning microscopy and SFM. A mean density of ca. 3 [Fe(PcS₄)] molecules per nm² and a wall thickness of 2.7 ± 0.2 nm for each PDDA/[Fe(PcS₄)] bilayer were obtained. The characteristic maximum absorption of [Fe(PcS₄)] in the coating suggests that [Fe(PcS₄)] exists mainly in the form of an aquo complex [HOFe^III(PcS₄)]. The fabricated hollow capsules display a high stability in response to light irradiation and high temperature.