Determination of sorption properties, total heterogeneity, and fractal dimensions of carbon nanotubes

Abstract

Using special thermogravimetry and sorptometry methods physicochemical properties of carbon nanotube surfaces were investigated. A numerical and analytical procedure for the evaluation oftotal heterogeneous properties (desorption energy distribution and pore-size distribution functions) on the basis ofliquid thermodesorplion from the sample surfaces under the quasi-equilibrium conditions are presented. The desorption energy distribution was derived from the mass loss Q-TG and the differential mass loss Q-DTG curves of thermodesorption of pre-adsorbed polar and apolar liquid films. It is shown that the samples are highly sensitive to benzene vapour because the mechanism of liquid adsorption depends largely on the active surface centres and molecular interactions. For the first time, the evaluation ofthe fractal dimensions of nanotubes using the sorptometiy and thermogravimetry data is presented.

Quantitative Characterization of Hydrophilic−Hydrophobic Properties of MWNTs Surfaces

“…Following the suggestion of Tang et al, the FHH method was applied only to the near-monolayer coverage section of the adsorption isotherm when calculating the surface fractal dimension ( D S ) of the samples. In agreement with the data reported by Staszczuk et al, the surfaces of our MWCNT samples also show self-similar characteristics as evident from the D S values fluctuating around 2.5. While thermal treatment does not seem to affect surface fractal characteristics, the dimensionality of the capillary condensation ( D CC ) decreases monotonically with increasing temperature.…”

Fractal analysis of carbon nanotube agglomerates obtained by chemical vapor decomposition of ethylene over nickel nanoparticles

“…For example, the values of the fractal dimension of CNT obtained using thermogravimetric analysis, an adsorption experiment, and atomic force microscopy are in good accord with each other [11].…”

On Application of Hyperfree Energy for the Description of Thermodynamics of Mobile Components in Nonstoichiometric Partially Open Ceramic Systems

“…Afterward, owing to temperature scattering, oxygen also is inclined to occupy some forbidden O(5) sites, effectively reducing thus the diffusivity free path for the probing atoms of argon through the lattice, see left diagram. Such specificity is provided by the so-called optometric measurements designed to analyze the surface/bulk heterogeneity, which helps revealing its true fractal-like dimensions [62]. For example, the distribution of pore size for HgBa 2 Ca 2 Cu 3 O 8+δ was calculated from nitrogen adsorption obtaining over the size range between 1.7 and 300 nm and revealing the related fractal dimension, the value of which was calculated to lie close to 2.5.…”