TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Flow Field Structure: The flow field structure comprises several hydrophobic parts and several hydrophilic parts in communication with each other. The hydrophobic parts and hydrophilic parts are hydrophobic channels and hydrophilic channels, respectively. The hydrophobic and hydrophilic channels comprise a porous material. The porous interface has a porosity of 30-100%, in communication such that a liquid, vapor, and/or gas can flow between the hydrophilic and hydrophobic parts. The hydrophobic channels and hydrophilic channels are provided in an alternating configuration, random configuration, and interlocking configuration. The number of hydrophobic channels is equal or greater than or less than the number of hydrophilic channels. The structure comprises 2 to 20 hydrophobic channels and 2 to 20 hydrophobic channels, where each channel has a span to width ratio of 1/2 to 1/10. The hydrophobic part comprises Teflon (RTM: polytetrafluoroethylene) (5-60)%. The flow field structure further comprises a manifold in communication with the hydrophobic part or the hydrophilic part, where the flow field is comprised within an electrochemical cell. The flow field structure is comprised within a separator plate for a fuel cell stack. Preferred Method: The flow field structure is provided in the separator plate or frame, where the sub layer for humidifying gas comprises a porous material. The liquid, gas, and/or vapor introduced and removed from the electrochemical cell comprises H2 or water.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The hydrophobic part and hydrophilic part comprise graphitic carbon fiber mat, fiber cloth, graphitic carbon paper, sintered metal, metal forms, mesh, screen, and/or reticulated vitreous carbon (preferably graphitic carbon paper). The hydrophilic part comprises Nafion (RTM: sulfonated tetrafluoroethylene based fluoropolymer-copolymer) (1-70)%. The graphitic carbon paper is Toray (RTM: graphitic carbon paper). EXAMPLE - No suitable example is given.