Ostwald's ripening of single-layer carbon nanotubes

摘要

Analysis of experimentally obtained size distribution functions in the form of percentage of carbon nanotubes (CNTs) versus their diameters shows increasing intermediate tube diameters with increasing concentration of the source of carbon atoms. In this paper, the mechanism of growth is associated with Ostwald's ripening CNTs, which are considered massive cylindrical nanoclusters of various diameter and height embedded in a solution (volume or surface) of carbon atoms. Interaction of nanoclusters is realized through the Gibbs-Thomson effect, resulting in increasing their average diameters. Validity of the proposed mechanism of increasing average diameters of nanotubes is proved by comparison of the experimentally obtained histograms with theoretically computed dependences. We use the generalized Lifshitz-Slyozov-Wagner and the Chakraverty-Wagner distributions, both computed via assumption that growth of nanoclusters (nanotubes) is controlled simultaneously by (volume or surface) diffusion and by speed of chemical connections' formation or by chemical reaction (Wagner's mechanism of growth). Under specified technological parameters and conditions of synthesis, the obtained theoretically distributions fit well with the experimental histograms for single-layer CNTs. (C) 2016 Optical Society of America