Xiujuan J. Dai

An environmental friendly route to synthesize titanium dioxide nanotube powder is developed using a semi‐batch reactor set‐up that combines both anodization and the plasma treatment of water. A constant supply of the reactive plasma species, such as nitrate and hydrogen peroxide, in the semi‐batch reactor facilitates the formation of titanium dioxide nanotubes during the anodization of titanium. The results are compared against a conventional batch reactor set‐up that uses the same plasma‐treated water constantly during the anodization, which impacts the quality of the nanotubes produced. The semi‐batch reactor set‐up resulted in the formation of powders of titanium dioxide nanotubes with better physical and chemical qualities than those produced in the batch set‐up.

An environmentally friendly electrolyte for the synthesis of titanium dioxide nanotubes by anodization is presented. Plasma treatment of de‐ionized water produces some important reactive species such as nitrate and hydrogen peroxide. This plasma‐treated water serves as an efficient electrolyte in the formation of titanium dioxide nanotubes during anodization. In order to further understand the roles of nitrate and hydrogen peroxide, titanium foil was anodized in plasma treated water containing nitrate or/and hydrogen peroxide as well as in its equivalent solution made by adding nitric acid and/or hydrogen peroxide to water. It was found that the plasma treated water containing both nitrate and hydrogen peroxide produced more uniform arrays of highly crystalline titanium dioxide nanotubes than produced in the aqueous solution made with nitric acid and hydrogen peroxide.

A functionalization of microstructures of polyhedral oligomeric silsesquioxane (POSS) to obtain substrates contain N‐moieties, with a probable high selectivity of primary mines is demonstrated for the first time in a low pressure plasma process through a sequential continuous wave plus pulsed mode (CW + P). Selective grafting of N‐moieties was performed across octa‐methyl POSS micro‐powder by substituting hydrogen atoms of the terminal methyl groups during nitrogen/hydrogen (N₂/H₂) gases plasma. As opposed to wet chemical functionalization approaches, the plasma method does not require reactive chemicals and is environmentally friendly. The results demonstrate the efficiency of the treatment (N/Si) reaches 7.1% with an indication of high NH₂ selectivity (NH₂/N). The amount of primary amines is determined from XPS data after 4‐(trifluoromethyl) benzaldehyde (TFBA) chemical derivatization.