Papers by Author: Ning Wang

Abstract: Ceramic oxide coatings were produced on pure titanium by plasma electrolytic oxidation in different electrolytes. The variation of coating thickness with applied voltages revealed coating almost kept a steady-state growth rate in electrolyte A and B, but not for electrolyte C. Numerous nodules occurred on the surface of the coatings at 200V in electrolyte A and B, and then nodules disappeared with the applied voltage increasing to 300V. There was no nodules occurred, and pore size was evidently different in electrolyte C. When the applied voltage was 300V, the coating formed in electrolyte C exhibited the highest corrosion potential and lowest corrosion current density in 3.5% NaCl aqueous solution.

Abstract: Pristine multi-walled carbon nanotubes (P-MWNTs) were functionalized with 4-substituted benzoic acid via ‘‘direct’’ Friedel-Crafts acylation in mild reaction medium of polyphosphoric acid (PPA)/phosphorous pentoxide (P2O5). Raman spectroscopy, thermogravimetric analysis, transmission electron microscopy were applied in this paper to demonstrate that multi-walled carbon nanotubes inherently have functional groups on their surfaces as a result of the reaction. The overall evidence indicates that the 4-substituted benzoic acid functionalization of carbon nanotube can be achieved without oxidation as pre-treatment. Thus, aryl carbonyl moieties with different length of 4-substituted alkyl acyl amine functionalized MWNTs（F-MWNTs） can be synthesized simply, without disrupting the primary structures of the nanotubes.