Peculiarities of Surface Modification of Polyamide Membranes by Cobalt Phthalocyanine

Abstract

Membrane technologies play an important role in the modern world, causing the progress of chemical, petrochemical, energetical and other industries. However, the potential of polymeric membranes and membrane technologies has not been exhausted. Functionalization of polymeric materials by macroheterocycles and their metallocomplexes is an interesting approach for obtaining the new materials with unique properties (selective conductivity, catalytic activity, etc.). In this regard this article is devoted to the study of the surface modification of polymeric membranes by phthalocyanine metallocomplexes. Polyamide porous membranes were purchased from NPO “Technofilter” (Russia) and chosen as the polymeric substrate. Sodium salt of cobalt octahydroxyphthalocyanine (OHPcCo) and solution of 1,4-dibromobutane (DBB) in heptane were used for functionalization of the surface and modifying polycaproamide membranes. Spectral effects of the surface modification were studied by UV–Vis and IR spectroscopy. Absorption spectra of OHPcCo in the surface layer of the membrane were observed. The spectral data indicate that immobilization of OHPcCo occurs due to its surface polycondensation with a bifunctional dibromobutane and its chemical binding with amino groups of polymer membrane. The atomic-force microscopy data were examined to confirm the immobilization and to study the phthalocyanine polymolecular layers. The effect of modification on structure of the polymeric membranes was studied. It is shown that the surface immobilization of catalytic centers does not result in any significant change in porosity and specific surface of the membranes. The amount of adsorbed phthalocyanine on the membrane surface was estimated. The average thickness of absorbed layer was calculated.