Biomedical Engineering Reference
In-Depth Information
radicals, hydrocarbons, oxygen, carbon dioxide, or even ammonia
[64]), and more complicated patterns combining these adsorbates
would need to be tested.
In addition to this, it may be necessary to include physisorption
events and surface reactions. The use of DFT during the computational
parameterization prohibits the investigation of physisorption in this
case, since DFT is unreliable for the calculation of the physisorbed
states. Furthermore, since this is a thermodynamic model, it assumes
spontaneous adsorption of all constituents independent of species.
Pre-adsorption or post-adsorption reactions are beyond the scope
of this model, but could be surmised using standard formation
enthalpies for simple molecules in the H/N/O phase diagram, and
included via additional kinetic functions.
Figure 7.14
Relative stability of pristine and adsorbate-coated nanotubes,
with (a) 2%, (b) 4%, (c) 6%, and (d) 8% total coverage of H, O,
H
O, and N. Reproduced with permission from Ref. [58] IOP
Copyright Publishing, 2009 and Institute of Physics, UK.
2
7.5
Modeling Carbon Nanotubes in Air
Although this model and the parameterization provided above, has
applicability to a range of different gas mixtures, the most prevalent
