Oxygen diffusion via cobalt-porphyrin complexes fixed in a polymer matrix

Molecular oxygen diffusion through the [α,α′,α″,α‴-meso-tetrakis(o- pivalamidophenyl)porphinato]cobalt(II) (CoP) complexed with various ligands and fixed in a transparent and rubbery poly(butyl methacrylate) membrane was studied. Oxygen-binding kinetic and equilibrium constants of the CoP complexes in the membrane are spectroscopically in situ determined. The diffusion coefficients of the dissolved oxygen according to Henry's law and the adsorbed or coordinated oxygen to the complex according to the Langmuir isotherm are evaluated by analyzing oxygen permeation behavior through the membrane in terms of the combination of dual-mode transport theory and the spectroscopic data. The oxygen diffusion coefficient via the CoP complex increases with the oxygen-dissociation kinetic constant from the CoP complex.