Carbon nanotubes surface, properties

Chirila V, Marginean G, Brandi W (2005) Effect of the oxygen plasma treatment parameters on the carbon nanotube surface properties Sur Coat Techn 200 548-551... 

Adsorption significant adsorption and interaction phenomena occur between carbon nanotubes and gases. There are two possible applications for this sector. The first is characterized by the molecular adsorption, which is related to carbon nanotube electrical properties and, then, with the possibility of developing chemical sensors. The second includes gas storage and separation due to the high surface area of carbon nanotubes. 

Of particular importance to carbon nanotube physics are the many possible symmetries or geometries that can be realized on a cylindrical surface in carbon nanotubes without the introduction of strain. For ID systems on a cylindrical surface, translational symmetry with a screw axis could affect the electronic structure and related properties. The exotic electronic properties of ID carbon nanotubes are seen to arise predominately from intralayer interactions, rather than from interlayer interactions between multilayers within a single carbon nanotube or between two different nanotubes. Since the symmetry of a single nanotube is essential for understanding the basic physics of carbon nanotubes, most of this article focuses on the symmetry properties of single layer nanotubes, with a brief discussion also provided for two-layer nanotubes and an ordered array of similar nanotubes. 

These properties are illustrative of the unique behavior of ID systems on a rolled surface and result from the group symmetry outlined in this paper. Observation of ID quantum effects in carbon nanotubes requires study of tubules of sufficiently small diameter to exhibit measurable quantum effects and, ideally, the measurements should be made on single nanotubes, characterized for their diameter and chirality. Interesting effects can be observed in carbon nanotubes for diameters in the range 1-20 nm, depending... 

Due to their moderate specific surface area, carbon nanotubes alone demonstrate small capacitance values. However, the presence of heteroatoms can be a source of pseudocapacitance effects. It has been already proven that oxygenated functional groups can significantly enhance the capacitance values through redox reactions [11]. Lately, it was discovered that nitrogen, which is present in carbon affects also the capacitance properties [12]. 

Nanocarbon structures such as fullerenes, carbon nanotubes and graphene, are characterized by their weak interphase interaction with host matrices (polymer, ceramic, metals) when fabricating composites [99,100]. In addition to their characteristic high surface area and high chemical inertness, this fact turns these carbon nanostructures into materials that are very difficult to disperse in a given matrix. However, uniform dispersion and improved nanotube/matrix interactions are necessary to increase the mechanical, physical and chemical properties as well as biocompatibility of the composites [101,102]. 

Zhan, Y., et al., Preparation, characterization and electromagnetic properties of carbon nanotubes/Fe304 inorganic hybrid material. Applied Surface Science, 2011. 257(9) p. 4524-4528. 

---