Direct Methanol Fuel Cell: Infrared Study Of Nafion～(?) Membrane And Studies On Methanol-Crossover-Depressed Membrane

Infrared Spectroscopy is an effective method to study polymer materials. Thework in this thesis focuses on the use of attenuated total reflectance (ATR) techniqueand infrared microscope in the material study of Direct Methanol Fuel Cells(DMFCs). Comparison of the transmission spectrum and ATR spectrum shows thecomposition difference between membrane surface and bulk. It is likely sulfonicacid group is enriched in the membrane surface and the result affects the protonconductivity for the surface and the bulk. During thermal treatment, Nafionmembrane is found to change in the micro-structure through calculation of therelative absorption intensity ratio of different groups. It is achieved to decrease thesurface energy through side chain movement when the membrane was treated attemperatures above glass transition temperature. It can be concluded sulfonic acidgroup moves from bulk to the surface slightly. And this degree increases with thetreatment temperature. Infrared microscope was applied to study the distribution ofpolymer in the surface of composite bipolar plate material. It is found that polymeradhesive is relatively uniform for the press molded polymer-filler compositematerial.Organically modified silicon oxide (ORIMOSIL)|Nafion composite membranewas formulated through in-situ hydrolysis of triethoxymethylsilane (TEMS) in thenanophase-separated morphology of perfluorosulfonic acid (PFSA) membrane. Bycontrolling the condition, composite membrane with ORIMOSIL content of 10%shows about 50% decrease of methanol crossover at 80℃, compared withNafion?115 membrane. However proton conductivity of composite membrane is 4times lower than the original membrane.