OXYGEN PERMEABILITY AND DIFFUSIVITY IN POLYMER MEMBRANES IMMERSED IN LIQUIDS

A membrane-covered-electrode was employed to measure oxygen permeability and diffusivity through polymer membranes immersed in liquids. Generally, values of oxygen permeability and diffusivity agreed fairly well with those determined in an ambient gas (air). Platinum and silver were studied as the cathode material. Regarding the indicial response to the step-change of oxygen partial pressure, the platinum cathode did not exhibit sometimes the first-order response, whereas the response of the silver cathode was of the first-order all the time. A specific response, if any, other than that of the first-order was elaborated from the viewpoint of mass transfer resistance involved in a series of the membrane, the electrolyte layer and the electro-chemical reaction at the cathode surface. If platinum is used as the material of cathode, special attention such that the first-order response can be realized; otherwise, the determination is subjected to an appreciable error. © 1969.