Inter-tube distance

The presence of residual surfactant on the CNT surface could also play an important role on the inter-tube distance. Changes in the matrix glass transition temperatures have been observed in CNT/ polymer composites, and this effect was attributed to adsorption of polymer onto the CNT interface [i.e., displacement of the SDS layer, predominantly by the low molar mass part of the MWD]. ... 

Figure 4.9 Theoretical shifts of the percolation threshold due to changes in the inter-tube distance [f], or in the number of junctions of CNTs in two polymeric matrixes with different MWDs. Connectedness criterion [A] and CNT diameter [D] are as defined in Chapter 1. [Reprinted from reference 20, with permission from e-PoIymers],...

An X-ray tube with a tungsten target and which serves as the source in an X-ray wavelength dispersive fluorescence spectrometer is equipped with a crystal of ethylenediamine tartrate. The plane of reflection in use corresponds to an inter-reticular distance of d — 4.404 A. 

Thus, inter-atomic distances and the atomic state in Tetracarbon are fundamentally different from all the known forms of carbon. The differences between clear and hard diamond on the one hand, and soft and black graphite on the other hand, illustrate the differences among Tetracarbon and other forms of carbon. The distance between the neighboring sp -carbon atoms within the Tetracarbon chain is about 1.3 A, whereas the distance between the carbon chains is 4.80-5.03 A. It is interesting to note that in some respects Tetracarbon is similar to tubulenes, as it can be considered as tubulene in the limit when the diameter of the tube approaches the diameter of carbon atom. Nevertheless, in Tetracarbon the hybridization state of carbon atoms changes from sp to sp. It is basically a new purely one-dimensional sp -carbon modification with one-dimensional electron band structure, whereas tubulene is a quasi-one-dimensional material in which the number of one-dimensional electron bands increases with increasing tubulene diameter. Tetracarbon and tubulene are also similar in that the carbon chains in Tetracarbon are oriented normally to the surface of the film, similar to the orientation in tubulene. 

In this equation, the connectedness criterion [A] embraces the nature of the inter-tube junctions, as it describes the efficiency of electron tunneling between adjacent tubes. The value of A is set by the electron tunneling distance [f], the value of which presumably is influenced by the temperature and by the electronic states of the CNTs, the contact potential barrier, and the electrostatic... 

Figure 6.1 Reducing the band-gap of the material within the inter-tube junction to increase the electron tunneling distance (left] and the desired final composite morphology (right].

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