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Abstract: H3PW12O40 (12-phosphotungstic acid; PWA) is efficient catalysts for the selective oxidation of alkanes, aldehydes, and perfluorinated acids. However, PWA molecules are high solubility in water and this property has been making it difficult to utilize as an industrial catalyst. In this study, the water-insoluble PWA-conjugated chitosan matrix was prepared by mixing the aqueous PWA and chitosan solutions. This conjugate matrix was constructed by the electrostatic interaction between amino group of chitosan and negative charge of PWA and showed the thermal stability at <100°C. In addition, the PWA-conjugated chitosan matrix indicated the property for triphase catalyst as epoxidation of allylic alcohols, such as cinnamyl alcohol, farnesol, and so on. The isolated yield of epoxidation with the conjugate matrix was as same as that of pure PWA. Furthermore, since this conjugate matrix did not dissolve in water, matrices could easily separate from the reaction solvent and recycle more than 3 times. Therefore, the PWA-conjugated chitosan matrices may have a potential to utilize the novel catalyst for the epoxidation of various allylic alcohols. [Copyright &y& Elsevier]

Abstract: Double-stranded DNA is one of functional polymers, but the large amounts of DNA sources, such as salmon milt and shellfish gonads, have been discarded as industrial wastes. Therefore, conversion of this discarded DNA to be a useful material would be beneficial to utilize the unique property of DNA. These materials including DNA have been prepared by mixing with the organic polymers, such as alginic acid, collagen, and chitosan. However, since these materials have consisted from entirely organic components, these do not have the mechanical strength for a material. So, we prepared the organic–inorganic hybrid materials by mixing DNA with silane coupling reagents bis(trimethoxysilylpropyl)amine or bis[(3-trimethoxysilyl)propyl]ethylenediamine. These hybrid materials with the flexibility were water-insoluble and resistant to hydrolysis by nuclease. In addition, the mechanical strength of this hybrid material was approximately twice as high as that of DNA without mixing with silane coupling reagents. Furthermore, the double-stranded DNA in the hybrid materials has been maintained in a B-form structure in aqueous solution. Thus, we demonstrated the utilization of DNA as a functional material. As a result, this material could selectively accumulate harmful DNA-intercalating compounds with the planar structure, such as dibenzo-p-dioxin, dibenzofuran, and ethidium bromide. Organic–inorganic hybrid material including double-stranded DNA has potential to serve as a useful biomaterial for medical, engineering, and environmental applications. [Copyright &y& Elsevier]

Abstract: Large amounts of DNA-enriched biomaterials, such as salmon milts and shellfish gonads, are discarded as industrial waste around the world. We could convert the discarded DNA into a novel bio-matrix by the hybridization of DNA and metal ions, such as Al3+, Cr3+, Fe2+, Fe3+, Cu+, Cu2+, Zn2+, and Cd2+. These water-insoluble DNA-metal ion matrices could be created in various desirable forms, such as a gel, capsule, film, or fiber. DNA-Al3+ matrices were found to maintain a B-form DNA structure, which was the native double-stranded DNA structure in water. The DNA-Al3+ fiber showed flexibility with the molecular orientation in the direction of drawing. When a DNA-Cu2+ matrix was incubated in an aqueous hydroquinone or ascorbic acid solution, benzoquinone or dehydroascorbic acid was produced, respectively, by the oxidative effect of Cu2+ in the DNA-metal ion matrix. These results suggest that metal ions in the DNA-metal matrix maintained the oxidative function. The water-insoluble DNA-metal ion matrices may have a potential utility as a functional bio-material, such as an antibacterial, oxidative, bio-sensor, and ion conductive materials. [Copyright &y& Elsevier]

Abstract: The development of anhydrous proton conducting membrane is important for the operation of polymer electrolyte membrane fuel cell (PEMFC) at intermediate temperature (100–200°C). In this study, we have investigated the acid–base hybrid materials by mixing of strong phosphonic acid polymer of poly(vinylphosphonic acid) (PVPA) with the high proton-exchange capacity and organic base of heterocycle, such as imidazole (Im), pyrazole (Py), or 1-methylimidazole (MeIm). As a result, PVPA-heterocycle composite material showed the high proton conductivity of approximately 10−3 Scm−1 at 150°C under anhydrous condition. In particular, PVPA-89mol% Im composite material showed the highest proton conductivity of 7×10−3 Scm−1 at 150°C under anhydrous condition. Additionally, the fuel cell test of PVPA-89mol% Im composite material using a dry H2/O2 showed the power density of approximately 10mWcm−2 at 80°C under anhydrous conditions. These acid–base anhydrous proton conducting materials without the existence of water molecules might be possibly used for a polymer electrolyte membrane at intermediate temperature operations under anhydrous or extremely low humidity conditions. [Copyright &y& Elsevier]

Abstract: Recently, membranes with high anhydrous proton conducting have been attracted remarkable interest for the application to the polymer electrolyte membrane fuel cell (PEFC). In this paper, we have investigated the anhydrous proton conductor consisting of alginic acid (AA), one of the acidic biopolymers, and imidazole (Im). This AA–Im composite material showed the proton conductivity of 2×10-3Scm-1 at 130°C under anhydrous conditions. Additionally, these AA–Im composite materials have the highly mechanical property and thermal stability. Furthermore, the biological products, such as biopolymer, are cheap, non-hazardous, and environmentally benign. The proton conductive biopolymer composite material may have the potential for its superior ion conducting properties, in particular, under anhydrous (water-free) or extremely low humidity conditions. [Copyright &y& Elsevier]