A new type of fluorine‐containing polybenzimidazole, namely poly(2,2′‐(2,2′‐bis(trifluoromethyl)‐4,4′‐biphenylene)‐5,5′‐bibenzimidazole) (BTBP‐PBI), was developed as a candidate for proton‐conducting membranes in fuel cells. Polymerization conditions were experimentally investigated to achieve high molecular weight polymers with an inherent viscosity (IV) up to 1.60 dl g–1. The introduction of the highly twisted 2,2′‐disubstituted biphenyl moiety into the polymer backbone suppressed the polymer chain packing efficiency and improved polymer solubility in certain polar organic solvents. The polymer also exhibited excellent thermal and oxidative stability. Phosphoric acid (PA)‐doped BTBP‐PBI membranes were prepared by the conventional acid imbibing procedure and their corresponding properties such as mechanical properties and proton conductivity were carefully studied. The maximum membrane proton conductivity was approximately 0.02 S cm–1 at 180 °C with a PA doping level of 7.08 PA/RU. The fuel cell performance of BTBP‐PBI membranes was also evaluated in membrane electrode assemblies (MEA) in single cells at elevated temperatures. The testing results showed reliable performance at 180 °C and confirmed the material as a candidate for high‐temperature polymer electrolyte membrane fuel cell (PEMFC) applications.

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Nanotubes and nanowires have shown great potential in a broad range of applications from nanocomposite, nanoelectronics to nanoelectromechanical systems. The small dimensions of such materials also impose a tremendous challenge for experimental studies of their intrinsic mechanical, electrical and other device related properties. The present research has developed four degrees of freedom nano mechanical manipulation system for use inside a scanning electron microscope (SEM). This manipulation system is used to monitor three dimensional nano manipulation processes and study the mechanical response of crystalline boron nanowire (BNW). Crystalline boron nanowire is synthesized by vapor liquid solid (VLS) technique. The electron beam induced deposition (EBID) method is used to clamp boron the nanowire to the AFM tip inside the SEM vacuum chamber. The mechanical property of the BNW is measured by applying continuously increasing load on it. SEM image can analyze the deformation and buckling behavior of the boron nano wire.Transmission electron microscopy (TEM) and atomic force microscope (AFM) were used to measure the cross-sectional area of nanowire. The Young's modulus of the boron nanowire has been measured to be 117± 4.1 GPa.

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