Abstract Submitted to the    NANOTUBE'04 Conference:

Recently carbon nanotubes have generated a great deal of attention because of their interesting properties. Their one-dimensional nature results in exciting electrical, mechanical and optical properties. While these materials can now be produced in large quantities, purification, dispersability and processability have always been serious issues. Recently, alternative one-dimensional inorganic nanowires have been demonstrated. The most promising of these are the Mo6S9-xIx family. These materials have the advantage that they are easy to fabricate, all nanowires are metallic and all have the same diameter. In addition they can easily be dispersed in various solvents. These properties suggest Mo6S9-xIx to be one of the most promising one-dimensional nano-materials. However, issues such as the optimum solvent, maximum solubility, polymer stabilisation and nanowire bundling have not been studied. Here we present a quantitative study of the dispersion properties of Mo6S4.5I4.5 nan owires. Optical absorption based sedimentation studies have been carried using a large range of solvents showing Isopropanol to be the best. To clarify the sedimentation process we propose a theoretical model to correlate the local nanowire concentration with sedimentation time. Combining experiment with theory, these sedimentation studies show three phases to be present in the as produced material: approximately one third impurity material, one third insoluble nanowire bundles and one third soluble nanowire bundles. In addition sample purification can be attained by controlling the sedimentation time. The soluble fraction can also be increased by addition of small amounts of suitable polymers. Futhermore, TEM studies show a variation of the mean bundle diameter with dispersion concentration. This highlights the possibility of controlling the mean diameter of the nanowire bundles by controlling the initial concentration of the solution.