Effect of a fluoro-coating on oxygen transport performance and lifetime of a polymer-cobaltporphyrin membrane

A membrane having a long lifetime was prepared by spin-coating a perfluororesin on the polymer-cobaltporphyrin membrane, while the coating had no significant effect on the oxygen permeability and oxygen/nitrogen selectivity of the membrane. The oxygen-binding properties of CoP and facilitated oxygen transport of the coated membrane were also studied. It was found that CoP fixed even in the coated membrane had rapid and reversible oxygen-binding properties in response to the partial oxygen pressures and the apparent oxygen-binding equilibrium constants of CoP were not influenced by the coating. Oxygen permeation was selectively facilitated with CoP fixed in the perfluororesin-coated membrane, whereas the water vapor permeability was significantly suppressed in comparison with that of the uncoated membrane. With increasing the coating thickness, the oxygen permeability coefficients slightly decreased, but the water vapor permeability coefficients significantly decreased. The lifetime of the CoP as an oxygen-carrier in the perfluororesin-coated membrane was prolonged, which was attributed to the hydrophobic property of the coating.