This Small Business Innovative Research Phase II project will demonstrate practical and cost-effective designs for a high energy density Proton Exchange Membrane (PEM) Fuel Cell. The approach taken will utilize the treatment of membranes with Interpenetrating Polymer Networks (IPN), as demonstrated in Phase I, to create regions with enhanced strength and the desired ionic, reactant and water transport properties for a viable Segmented Fuel capable of operating with ambient diffused oxygen for portable applications. A systematic modeling procedure will be developed to generate optimal, thermally and hydraulically stable segmented fuel cell designs, with specific electrode arrays, given voltage, and power requirements. Size/weight trade-offs will be considered.<br/><br/>The work supports the effort to develop fuel cells for portable consumer and industrial power which is safe, durable and energy efficient. PEM based fuel cells are a mature technology which takes advantage of very simple chemistry and the introduction of the GES IPN-improved membranes will permit designers greater flexibility in producing fuel cells which meet the needs for portable computers, tools, communication, medical and industrial equipment.