The permeability, diffusivity and solubility of gas in rubbery polymer membrane have been studied using a pseudononequilibrium　molecular dynamics (MD) simulation. We employed the ‘permeation simulation’ composed of　gas/membrane/vacuum, and another is the ‘sorption simulation’ composed of gas/membrane/gas. In both models,　the adoption of the virtual liquid molecules, which have no interaction with the gas molecules, allowed the control of　the system pressure that led to the quantitative transport simulation analogous to the real experiments. The permeation　coefficient, the mutual diffusion coefficient and solubility coefficient of oxygen in poly(dimethyl siloxane) at 298　K were directly obtained from the present MD simulation using the two simulation models. These calculated parameters　were comparable to the experimental values. The present method may be useful for obtaining information on　the microscopic aspects of the transport process of small molecules both at the interface and inside the rubbery polymer　membrane.

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Applications of molecular simulation to studies of gas permeation and separation through microporous inorganic　membranes are reviewed. Porous inorganic membranes have chemical and thermal stability, and they are expected　to be used for highly selective separation processes of several molecular mixtures. In order to adequately design　those membranes and to decide effective operation conditions, it is important to understand gas permeation and separation　mechanisms in ultra-microporoues on membranes from a microscopic viewpoint. A boundary driven nonequilibrium　molecular dynamics (NEMD) technique, which enables us to easily simulate a non-equilibrium state permeation,　is a useful tool for the understanding of gas permeation and separation phenomena in the scale of molecules.　Many papers have been presented for development of molecular simulation techniques and their application to　gas permeation and separation simulations on mainly three types of microporous inorganic membranes, zeolite,　amorphous silica and carbon membranes. Ideal membrane performance is successfully predicted by using molecular　simulations qualitatively, while structural and physical chemical adequacy of membrane model is important to reproduce　membrane performance observed experimentally for real membranes. Further development of molecular simulation　studies for microporous inorganic membranes would bring about more precise predictions of gas permeation　and separation properties.

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Computational chemistry studies on a liquid separation using the membranes were reviewed. There are several　types of membranes classified by their pore size, and different computational simulation methods were applied.　Computational fluid dynamics (CFD) is an efficient approach to study a colloidal rejection or cake formation on the　membrane surface in the microfiltration (MF) and ultrafiltration (UF). The advantage of a CFD is to evaluate the　effect of various forces acting on the colloidal particle with the consideration of fluid dynamics. CFD revealed the　detail mechanism of the particle deposition on MF and UF with providing the better understanding of the effect of　hydrodynamic and electrostatic interactions. In addition to CFD, a kinetic Monte Carlo approach is used to study a　formation of cake structure. Nanofiltration (NF) membranes and the membranes having smaller pore have been　investigated by molecular simulation techniques such as a molecular dynamics or non-equilibrium Monte Carlo.　These techniques reveal the atomistic behavior of solvent and solute, and enable to predict the permeation rate and　separation factor based on the atomistic interaction parameters. Some studies on the pervaporation in zeolite membranes　and pressure-driven liquid permeation in NF were introduced. Computational chemistry will be useful tool to　design the membrane system.

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Toward the practical application of polymer electrolyte fuel cell (PEFC), it is important to achieve the low humidity　operation for easier water management of the system, rapid start-up, and higher load following properties. For this　purpose, the development of polymer electrolyte working in low humidity condition is essential. To design the new　polymer electrolyte with higher proton conductivity in low humidity condition, fundamental understandings of electrolyte　materials at the atomistic and molecular level are important. In this manuscript, we reviewed recent research　activities on polymer electrolyte for PEFC by using the computational chemistry approach.

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Normal erythrocytes have biconcave discoid shape that presents large surface area with higher cell surface to volume　ratio than that of spherical shape. This appears to allow membrane internalization required for Plasmodium falciparum　(Pf) invasion into erythrocytes. Indeed abnormal erythrocyte shape with decreased surface area to volume　ratio such as hereditary spherocytosis limits invasion of the parasite. In the present study, using several agents to　induce erythrocyte shape changes, we examined whether echinocytic shape change with membrane projections in　opposite direction to membrane internalizations and/or stomatocytic shape change with decreased surface area to　volume ratio that would be required for internalization, prevent Pf invasion. Having microscopically confirmed　echinocytic and/or stomatocytic shape changes and also measured extensibility using an ektacytometer of the treated　cells, subsequent Pf invasion assay was performed and parasitaemia determined. Both sodium flouride (NaF) and　phospholipase A2 (PLA2) induced echinocytic change whereas phospholipase D (PLD), sphingomyelinase (SMase)　and chlorpromazine (CPZ) caused stomatocytic change with decreased extensibility of erythrocytes. In both situations,　Pf invasion was prevented, indicating that biconcave discoid shape of normal erythrocytes with high surface to　volume ratio is required for membrane internalization when Pf invades into erythrocytes.

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A thin carbonized polyimide membrane was formed on the surface of a nickel substrate with small pores by a spray　method. It was applied to an electrochemical system, which controls reactions by the electrode potential, to evaluate　the properties as a water-electrolysis electrode. Although the over potential for water-electrolysis was relatively high,　an electrochemical water decomposition reaction was carried out and a phenomenon of hydrogen permeation　through the membrane electrode was observed. From the relationship between the applied current density and the　amount of hydrogen permeating through the membrane electrode, it was estimated approximately 80% of the electrochemically　generated hydrogen permeates through the membrane electrode.
It was found that an electrochemical reaction and materials produced at the electrolyte/electrode interface separation　system is composed of a carbonized polyimide membrane electrode by using micro pores of the membrane　itself.

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An acid extractant, di (2, 4, 4-trimethylpentyl) phosphinic acid (Cyanex 272), was impregnated to the hydrophobic　ligand of a polymer chain grafted onto the pore surface of a porous membrane of a hollow-fiber form. The hydrophobic　ligand was introduced by a reaction of an epoxy group of the poly-glycidyl methacrylate, which was appended to　the porous membrane by radiation-induced graft polymerization, with n-alkylamine (CnH2n+1NH2) or n-octadecanethiol　(C18H37SH). The carbon number of the n-alkylamino group ranged from 0 to 18. The amount of Cyanex 272　impregnated onto the porous membrane increased with an increasing density of the n-octadecylamino group, whereas　the amount of impregnated Cyanex 272 was constant irrespective of the density of the n-octadecanethiol group.　No leakage of Cyanex 272 impregnated to the n-dodecylamino or n-octadecylamino group of the graft chain was　observed. The capturing of zinc ions by the Cyanex 272-impregnated porous hollow-fiber membrane was achieved　during the permeation of a zinc chloride solution through the pores of the porous membrane. The equilibrium binding　capacity of the Cyanex 272-impregnated porous hollow-fiber membrane for zinc ions was 0.37 mol/kg of the　GMA-grafted membrane.

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We have developed Portable Equipment for Manufacturing Transdermal Patch (PEM). This PEM has manufacturing　processes, casting membrane of a defined thickness, drying the membrane, covering a backing layer, and cutting　the patch, to make a matrix-type devices and runs automatically. Transdermal patches are prepared not only by a　conventional solvent-based method but also by a hot-melt method to prevent environment pollution. Quality of the　products (thickness, weight, and drug content) by PEM is superior to that by the Film Casting Device with Doctor　Blade (FCD). The release profiles from products are proportional to the square root of time, resulting it is an ideal　matrix-type patch. The coefficient of variation (CV) of release rate from the products at 6 hrs (1.5%) is less than that　from the product on the market (5%). Therefore, PEM is suitable for a teaching, training, and small scale manufacturing　in pharmacy colleges and pharmaceutical companies.

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