Facilitated oxygen transport membranes of picket-fence cobaltporphyrin complexed with various polymer matrixes

A series of membranes having a selective and reversible oxygen-binding capacity were prepared by complexing picket-fence cobaltporphyrin (CoP) as an oxygen carrier with various polymer matrixes. The oxygen-absorption isotherm and oxygen permeation in and through the membranes were properly analyzed by dual-mode models to give the physical solubility coefficient of oxygen (k(D)), the physical diffusion coefficient of oxygen through the membrane (D-D), and the apparent diffusion coefficient of oxygen for hopping between fixed carriers (D-C). The oxygen-binding equilibrium constant (K) of CoP was independent of the polymer matrix species. The D-C value was smaller than the D-D value, but the D-C/D-D ratio still remained in the range of 1/5-1/50, indicating that CoP fixed in the membrane reversibly binds oxygen and facilitates oxygen transport.