Selective synthesis of double helices of carbon nanotube bundles grown on treated metallic substrates

Abstract

Phone: þ52 55 5950 4275, Fax: þ 52 55 5950 4284Double-helix microstructures consisting of two parallel strands of hundreds of multi-walled carbon nanotubes (MWCNTs) have been synthesized by chemical vapour deposition of ferrocene/toluene vapours on metal substrates. Growth of coiled carbon nanostructures with site selectivity is achieved by varying the duration of thermochemical pretreatment to deposit a layer of SiO x on the metallic substrate. Production of multibranched structures of MWCNTs converging in SiO x microstructure is also reported.In the abstract figure, panel (a) shows a coloured micrograph of a typical double-helix coiled microstructure of MWCNTs grown on SiO x covered steel substrate. Green and blue show each of the two individual strands of MWCNTs. Panel (b) is an amplification of a SiO x microparticle (white) on the tip of the double-stranded coil (green and blue). The microparticle guides the collective growth of hundreds of MWCNTs to form the coiled structure.

Emerging double helical nanostructures

“…For instance, the very recent report by Cervantes-Sodi et al demonstrated that CNT-array double helices can also be available using lamellar SiO x particle-supported Fe NPs as the catalyst akes. 105,106 However, it should be noted that it still remains a challenge to synthesize a true CNT double helix in which each backbone is one individual CNT with its own helicity rather than one CNT array.…”