Surface graphitization, diamond corrosion

PTFE is a crystalline polymer consisting of twisted zigzag spirals with at least 13 repeating units per turn. This nonpolar polymer has a solubility parameter of 6.2 H, a high (327 C), and a heat deflection temperature of 121 C PTFE is a tough, flexible polymer which retains its ductility at extremely low temperatures (-269 0. The coefficient of friction of ptfe is the lowest of any known solid material (see Table 13.4). Films of ptfe can be bonded by adhesives to other surfaces if the polymer surface is treated with sodium. It also bonds to diamonds and graphite whose surfaces have been fluorinated. Liquid sodium removes fluoride ions from the surface and leaves free radicals on the polymer surface, ptfe is resistant to almost all corrosives and solvents, but it can be dissolved in hot perfluorinated kerosene, ptfe is difficult to mold or extrude. 

The support for the metal nano-particles turns out to be as important as the nano-particles for providing their dispersion and stability. Studies on electron transfer are particularly important for carbon-based materials because those materials, such as glassy carbon, graphite, fullerene, and diamond with different electronic and structural properties, have been proved to possess distinctly different electrochemical properties from each other (Ramesh and Sampath, 2003). Carbon supports provide high electronic conductivity, uniform catalyst dispersion, corrosion resistance, and sufficient access of gas reactants to the catalyst (Ismagilov et al, 2005). In addition to electrical conductivity and surface area, hydrophobicity, morphology, porosity, and... 

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