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Membrane in Polymer Electrolyte Membrane Fuel Cell (PEMFC) plays important role in electrochemical reaction within, which allow ion to pass, but prevent electron to pass through. Thus, membrane plays critical role in facilitating electrochemical reaction. Effort have been made to make membrane other than Nafion®. The new mentioned membrane is prepared by constructing supramolecular structure arise from hydrogen bond between sulfonated polystyrene (sPS) and polyethylene-graft-maleic anhydride (PE-g-MAH). Therefore, the understanding of new membrane's ability to conduct ion will be investigated with respect to its thickness. The immediate results show that thinner membrane gets better in the expected properties. This fact could be observed from the value of ionic conductivity which reaches a value of 10-5 S.cm-1. The initial results indicate thickness of the membrane affect water uptake into membrane, and the dense of membrane could also alter the ionic conductivity properties. [ABSTRACT FROM AUTHOR]

Superconductors are characterized by zero resistance and Meissner effect. At below critical temperature (Tc), these materials exhibit diamagnetic properties. On the other hand, materials in nano-crystal size have specific properties that differ from bulk state. Nanomaterials are characterized by surface effect which influences physical and chemical properties of the materials. Combining these two mayor fields, it can be obtained superconductors in nano-crystal size (below 200 nm) using simple method (called as nano-superconductors). Generally, ceramic-oxides in nano-crystal size, even in cuprate-superconductors, may have ferromagnetic behavior at room temperature. In this research, Bi and Bi, Pb-based nano-superconductors synthesized by wet mixing technique have Tc ∼80 K for 2212 (Bi2Sr2CaCu2O8-δ and Bi1,6Pb0,4Sr2CaCu2O8-δ) phases. They also exhibit ferromagnetism effect and hysteresis curve although at well above Tc. This is unusual phenomenon because superconductor materials are generally diamagnetic at below Tc and paramagnetic at normal state. This phenomenon is possibly due to magnetic moments which may possibly come from oxygen vacancies of the nanoparticles surface. [ABSTRACT FROM AUTHOR]