The status and research subjects of polymer electrolyte fuel cells have been reviewed. We also show our recent research results regarding Pt-dispersed polymer electrolyte membrane which suppresses methanol crossover in DMFC, electrocatalysts (highly active alloy cathode and CO-tolerant alloy anode), and CO-preferential oxidation catalysts.

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Development trend of fluorinated polymer electrolyte membrane was reviewed. Membrane characteristics and cell performance of various fluorinated membrane were measured under operating condition of fuel cell. Mechanical properties of PTFE fibril-reinforced membranes developed by Asahi Glass company such as modulus and tear strength were investigated, and compared with non-reinforced membranes. The fibril-reinforced membranes have shown conspicuous improvement while their electric resistance and cell performance were almost same as those of non-reinforced ones. Good durability of the fibril-reinforced membrane has been confirmed in the cell operation at 80 °C for 5800 hrs.

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This paper presents an overview of the possibility and problems of new proton-conducting polymer electrolyte membranes based on hydrocarbon polymers. Due to their chemical stability, high degree of proton-conductivity, and remarkable mechanical properties, perfluorinated polymer electrolytes such as Nafion^®, Aciplex^®, Flemion^®, and Dow membranes are some of the most promising electrolyte membranes for polymer electrolyte fuel cells. A number of reviews on the synthesis, electrochemical properties, and fuel cell applications of perfluorinated polymer electrolytes have also appeared. While perfluorinated polymer electrolytes have satisfactory properties for a successful fuel cell electrolyte membrane, the major drawbacks to large-scale commercial use involve high cost and low proton-conductivities at high temperatures and low humidities. Presently, one of the most promising ways to obtain high-performance proton-conducting polymer electrolyte membranes is the use of hydrocarbon polymers for the polymer backbone. The present paper attempted to summarize the synthesis, chemical and electrochemical properties, and fuel cell application of new proton conducting polymer electrolytes based on hydrocarbon polymers that have been made during the past decade.

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A new type of fuel cell materials, especially polymer electrolyte membrane (PEM), has been developed based on the systematic approach. In this approach, some functions needed for fuel cell applications are separated to some different materials. Pore-filling membrane has been developed, which is composed of substrate matrix and filling polymer and they have some different functions. This method leads to an excellent membrane. On the other hand, it is found that the suppression of methanol permeation and the proton conductivity have a trade-off relationship, with the same filling polymer. Therefore, based on this relationship, the performance of membrane has been able to control with the concept of pore-filling membrane. In addition to this, a mathematical model, which can couple the performance of PEM with its fuel cell performance, has been developed and subsequently used for selecting appropriate membrane for applications. The fuel cell performance has been estimated with the model based on some parameters, divided into physicochemical and structural properties. Some guideline and information have been obtained to design or select the materials, i.e., higher proton conductive membrane should be selected when higher current density is needed, whereas lower methanol permeable membrane should be selected when higher voltage is needed. Fuel cell system has complicated hierarchical structures. Therefore, it becomes virtually impossible to solve some problems for fuel cell application with partially specialized knowledge. Structural design of whole fuel cell system should be considered as for optimization of its performance and development of PEM, which can be used in actual applications. The systematic approach, reported here, will be one of the key methods.

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Protein refolding of denatured RNase A was studied using reversed micelles that were formed by a cationic surfactant. The refolding performance of the cationic reversed micelles was compared to that of the conventional anionic reversed micelles formed by sodium di-2-ethylhexyl sulfosuccinate (AOT). The denatured RNase A entrapped in the water pools of cationic reversed micelles was gradually renaturated by the addition of the redox reagent glutathione, and the refolding yield attained to more than 90% in 10 hours. The refolding method using the reversed micelles enables to reactivate a high concentration of denatured proteins, which can not be renatured by the ordinary dilution method. The cationic reversed micelles have an advatage that the recovery of renatured proteins is easy compared to that of the anionic AOT micelles. A small addition of alcohol improved the recovery yield and the proteins reactivated in the cationic reversed micelles were completely recoverd by the addition of 20% (v/v) ethanol. The recovered proteins were confirmed to possess a high activity similar to that of native RNase A.

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To obtain the information on the effects of a divalent cation (Ca²⁺) on the membrane properties of the lipid A analog, E5531, the particle size, zeta potential, membrane fluidity and pharmacokinetics were investigated in rats after the addition of calcium ion. Within a molar ratio for [Ca²⁺] / [E5531] ≤3, the presence of Ca²⁺ increased the zeta potentials of the E5531 membrane but had no effects on particle size. Ca²⁺ decreased membrane fluidity and the pharmacokinetics in rats. These effects of Ca²⁺ on the membrane properties of E5531 particles could be eliminated by the addition of EDTA.

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Due to the Dioxin restrictions by the Japanese Government, it is anticipated that thousands of waste incinerators are to be scrapped within the coming ten years.
We have developed a new filtration method to remove burned ash (Dioxins) from waste water generated from such scrapping process. This system is using Dynamic Filtration membrane and UF Membrane and it is space saving, energy saving, high quality, and environmental friendly system.

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