Nanotubes

Careful control of the ratio of compounds to one another and their proper selection allows for control over the synthesis and the nature of carbon nanotubes it yields. Steering the process in the right way affords long or short, single-, double- or multi-wall carbon nanotubes of predominantly metallic or semiconductive character.

Carbon nanotubes are one dimensional nanomaterials with extraordinary properties; they are lighter than cotton, 50x stronger than steel, more electrically conductive than copper and more thermally conductive than diamond. However they come in a range of forms, diameters and lengths. It is very important to find means of controlling the synthesis, so that a proper material for envisioned application is obtained. In our group, we are working towards this goal by molecular control of these materials directly at the synthesis process. Fine tuning of many synthesis parameters and proper selection of reactants have already enabled us to observe preferential growth of certain types of carbon nanotubes, controlling their diameters and enhancing their length. This resulted in harnessing some of the properties of nanotubes at the macro scale.

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To achieve something extraordinary, special conditions must be employed and it is no different in the case of carbon nanotubes. They can come in a variety of structures and sizes, and thus a precise control over their synthesis is required. There are a range of methods for producing carbon nanotubes but we will only focus here on the strategy we have put the most focus on which is chemical vapour deposition (CVD). Carbon precursor is introduced into a high temperature furnace where it reassembles to form long cylindrical structures with the help of a catalyst. The difficult part is in a proper selection of conditions. Numerous compounds bear carbon and could potentially be used for nanotube synthesis, but not all of them decompose exactly when our catalyst of choice is released. Additional compounds can be introduced along the carbon source and catalyst to facilitate the production of the nanotubes with the desired structure.

Careful control of the ratio of compounds to one another and their proper selection allows for control over the synthesis and nature of carbon nanotubes it yields. Steering the process in the right way affords long or short, single-, double- or multi-wall carbon nanotubes of predominantly metallic or semiconductive character.