Polymeric fullerene oxide films produced by decomposition of hexanitro[60]fullerene

Abstract

A new poly(fullerene oxide) thin film material has been fabricated by thermal activation and electron bombardment on hexanitro[60]fullerene (HNF) film deposited on a Au substrate, all under vacuum conditions. The reaction products in the polymerization process are analyzed by XPS, UPS, IR, TGA-MS and LDI-MS techniques. It is found that the main effect of thermal and radiation treatments is to induce cleavage of –NO bonds from HNF molecules resulted in the release of nitric oxide gas and the formation of fullerene-bound oxyradicals, C 60–O 6. Spectroscopic evidence strongly suggests that rearrangement of fullerenic nitro moieties into nitrito groups is involved in the HNF decomposition process prior to the generation of reactive oxyradical intermediates. Consequently, the intermolecular coupling reaction of these oxyradicals leads to carbon polymer networks containing oxygen-bridged fullerenes. The thermally generated polymeric thin film is stable up to 900 K. Electron bombardment is also effective in both the decomposition of –NO 2 groups and the removal of –OH groups present in HNF films. UV irradiation at 365 nm alone is shown to be not as efficient for the polymer formation.