Formation of multiwall fullerenes from nanodiamonds studied by atomistic simulations (original) (raw)

Three-Stage Transformation Pathway from Nanodiamonds to Fullerenes

Journal of Physical Chemistry A, 2011

The dynamics of structure evolution of nanodiamonds ranging from 22 to 318 atoms of various shapes is studied by density functional tight-binding molecular dynamics. The spherical and cubic nanodiamonds can be transformed into fullerene-like structures upon heating. A number of the transformed fullerenes consist of pentagons and hexagons only. Others contain squares, heptagons, and octagons. One simulated fullerene is an isomer of C 60. The temperature of the transformation depends on the size, shape, and orientation of initial cluster. To be transformed into onion-like fullerenes, the spherical nanodiamonds should have 200 atoms or more, while the cubic ones require 302 atoms or more. The time-resolved energy profiles of all the transformations clearly reveal three-stage transformation character. During the first stage, the energy reduces quickly due to converting sp 3 carbon with dangling bond at the surface into sp 2 one, and the formation of partial sp 2 envelope wrapping the cluster. For the second stage, energy decreases slowly. The remaining interior carbon atoms come to the surface through the hole in the sp 2 envelope, and similar amount of sp 3 and sp 2 atoms coexist. The third stage involves the closure of holes, accompanied by the detachment of C 2 molecules and carbon chains from the edges. The energy decreases relatively fast in this stage. The proposed three-stage transformation pathway holds for all the simulations performed in this work, including those with the instant heating.

Fullerenes and Nanodiamonds for Medical Drug Delivery

2021

Carbon is a chemical element has the ability of forming long carbonic chain. Due to its special electronic structure, each carbon atom can be linked with another carbon atom or with another element via single, double or triple covalent bonds. The special electronic structure of carbon atom affecting on its properties also affecting on its ability of existing in different forms called allotropes. During few last decades, new carbon-based nanomaterials have been described including fullerene, carbon nanotube, graphene and nanodiamond. These new allotropes attracted the interest of science and industry and became as a new and important class of materials due to its outstanding features which candidate for numerous applications. In parallel with new developments in nanomedicine especially in drug delivery field, the targeted delivery systems became an important to overcome the limitations of the old fashion systems. So, it become very important to translate this idea into reality. Fulle...