Research On The Ultrathin, Freestanding Proton Conducting Membrane Based Sio₂

Energy is the physical basic of human beings. Either in survival or development, human beings can not be without development of new energy, and the development of energy techniques and update of energy forms. Generally speaking, petroleum, coal,gas and so on are classed as conventional energy,while wind energy, solar energy and tidal energy are classed as new energy, which is one of the most noticed realm in human beings development. In the circumstance of the new energy's development, proton exchange membrane fuel cell is the most popular energy form, and is one of the realms which have large space and potential of development.In the present study, we succeeded in the preparation of a ultrathin, self-standing, less methanol permeable proton-conducting (PEI/PCGF)/SiO₂/(PEI/PCGF) membrane. Its sandwich structure appears to be crucial in the design of novel proton conducting organic/inorganic materials. Hydroxyl groups in the silica layer and amine groups on the PEI chain in PEI/PCGF layer contributed to proton conduction. The silica middle layer composed of silica framework and surfactant micelles was responsible for low methanol permeability. Lower and upper organic PEI/PCGF layers play an important role in the formation of large-sized, self-standing membrane, in which the cross-linking of epoxides greatly improves the mechanical strength of the membrane. Although the present study is limited to (PEI/PCGF)/SiO₂/(PEI/PCGF) membrane, our approach opens new possibilities for the fabrication of ultrathin, highly flexible electrolyte membrane in fuel cell, sensor and supercapacitor applications.