the present invention refers to polymeric membranes and its synthesis with combination of innovative characteristics at the level of the bi - soft segment polyurethane material and at the level of the structure as integral asymmetric membranes . the hemocompability properties — non - hemolytic , non - thrombogenic and no platelet adhesion — combined with the high fluxes of permeation of o 2 and co 2 have been designed for the use of the membranes in medical equipments that involve contact with blood like extracorporeal blood oxygenators and can be further designed for hemodialysers and imunnisolation barriers .