A fast effective route to pH-dependent water-dispersion of oxidized single-walled carbon nanotubes

摘要

Research on applications of carbon nanotubes (CNT) 1 in different branches of applied sciences and technologies have proved theses carbon nanostructures as ideal candidate materials for composite processing 2, catalytic supporting 3 and for molecular sensoring 4. In particular, water-solubilization of single-walled carbon nanotubes (SWNT) has been widely studied, since these materials have shown enormous potentiality of employment in biological aqueous media 5. Methods of water-solubilization substantially follow two strategies: i.e., direct solubilization, achieved by covalent attachment of polar functionalities to shortened SWNTs 6, and dispersion of integral SWNT frames, provided by polar surface functionalization 5,7, surfactant and polymeric additives 5. We have been investigating the large-scale aerobic oxidation processes occurring to different graphenic systems, after chemical reduction 8-11, reporting particularly the achievement of water-soluble fragmented SWNT derivatives 12. In this letter, we describe the synthesis of integral water-dispersible oxidized SWNT structures (WD-SWNTOx), that have been massively oxygenated through a fast application of the previously reported protocol. The achieved products display an interesting pH-dependent behaviour, being therein easily suspended in basic aqueous media and quantitatively precipitated under acidic conditions (Fig. 1).