Capillarity and silver nanowire formation observed in single walled carbon nanotubes

Abstract

Single walled carbon nanotubes (SWNTs) exhibit similar capillarity properties to those exhibited by multiple walled carbon nanotubes (MWNTs); SWNTs, previously filled in low yield (ca. 2%) by solution chemistry techniques, can be filled in high yield (up to ca. 50%) by the liquid phase method; compositions from the KCl-UCl 4 and AgCl-AgBr systems were used to fill SWNTs without causing them significant chemical or thermal damage; in the case of the latter, exposure to light or an electron beam resulted in the partial photolytic reduction of SWNT incorporated silver halides to continuous metallic silver 'nanowires' within the capillaries.

Filling Single Wall Carbon Nanotubes with Metal Chloride and Metal Nanowires and Imaging with Scanning Transmission Electron Microscopy

“…Since for the investigation of the properties of SWNT/metal nanocomposites a high filling fraction is desired, we did not further pursue the solution-phase filling process. Previous melt phase Z6.23.2 filling experiments resulted in continuously filled SWNTs with high filling fractions [3,5]. We therefore decided to investigate the filling from the melt.…”

“…The hollow interior of SWNTs offers a one-dimensionally confined space that can be filled with various materials or be used to carry out chemical reactions. SWNTs have been filled with alkali halides [3,4], among others. Various metal halides have been reduced within the confined space of the SWNTs, thus yielding metal nanowires [5].…”

Imaging and Characterization of Molecules and One-Dimensional Crystals Formed within Carbon Nanotubes

“…For example, for SWNTs filled with silver halides, the halide undergoes spontaneous photolytic decomposition, resulting in the formation of aligned 1D fcc silver nanowires. 10 Similarly, it has been possible to reduce incorporated RuCl 3 to the base metal (see preceding paragraph), and the formation of reduced lanthanide nanowires has also been reported. 16 As with encapsulated fullerene or endofullerene molecules, in situ e -beam reduction in a high-resolution transmission electron microscope can modify the filling material to form reduced clusters, as in the case of ZrCl 4 formed within SWNTs.…”

“…Mixtures of predominantly amorphous ternary-phase materials may similarly be introduced into SWNTs by exploiting the melting properties of the relevant phases. 10 SWNTs can now be filled with a wide range of solid-phase crystalline and noncrystalline materials including metals and metal salts, 1,9,10 oxides, 13,14 and helical iodine chains. 15 Further modifications are possible on such materials once they are incorporated within SWNTs.…”

“…Subsequently, SWNTs were filled without acidification by capillary wetting with molten mixtures of silver halides or mixtures of alkali halides and actinide halides. 10 The ability of a molten material to wet and fill SWNTs depends on the wetting criterion determined by Ebbesen for the filling of nanotubes with liquidphase media. 11 In general, the filling procedure entails heating as-made nanotubes with the molten salt or oxide to a temperature 100 K above the respective melting point of the filling material.…”