Carbon Nanotubes And Its Applications 3

Nanoprobes and sensors  

•Extremely small sizes, high mechanical strength and flexibility nanotubes may indispensable in their use as nanoprobes.

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•Nano probes-high-resolution imaging, nano-lithography, nanoelectrodes, drug delivery, sensors and field emitters •Biological molecules, such as DNA can also be imaged with higher resolution using nanotube tips, compared to conventional STM tips. 

•Nanotubes tips - surface manipultion.

•A pair of nanotubes can be positioned appropriately o an AFM tip, they can be controlled like tweezers to pick up an release nanoscale structures on surfaces.

•Functionalized nanotubes were used as AFM tips t perform local chemistry, to measure binding forces betwee protein-ligand pairs and for imaging chemically patterned substrates.

•Electromechanical actuators have been constructe using sheets

•The nanotube actuators would be superior to conducting polymer-based devices, since in the former no io intercalation is required.

•Nanotubes can be used as advanced miniaturize chemical sensors.

•The electrical resistivities of SWNTs were found t change sensitively on exposure to gaseous ambient containin molecules of NO2, NH3 and O2.   •The response times of nanotube sensors are at least a

Templates

•Nanotubes have been used as templates to creat nanowires of various compositions and structures.   •Filling and opening of carbon nanotubes in air: •Filling of nanotubes is critical because of the wetting characteristics of nanotubes.   •A whole range of experiments remains to be performed inside these constrained one-dimensional spaces.

•Carbon nanotubes are easily opened by simple chemica method of oxidation.

•Fullerenes, at the tips are more reactive than th hexagonal lattice of the cylindrical parts of the nanotubes.

•Hence, during oxidation, the caps are removed prior t any damage occurring to the tube body, thus easily creatin open nanotubes.

•Opening and filling of nanotubes in solution.

•In this methods an acid is first used to open the nanotube tip and to act as a low surface tension carrier for solutes to fill the nanotube hollows.

•Filled nanotubes can also be synthesized during the growth of nanotubes in an electric arc or by laser ablation.   •Electric arc- encapsulated nanotubular structures are created in abundance.

Others ways are: •Chemical funtionalization. •Intercalation and doping. •Vapor chemistry.