STABILISATION OF CARBON NANOTUBE SUSPENSIONS - Carbon Nanotubes: From Bench Chemistry to Promising Biomedical Applications - page 1

Chapter 1
STABILISATION OF CARBON NANOTUBE
SUSPENSIONS
Dimitrios G. Fatouros, a Marta Roldo b and Susanna M. van der Merwe b
a Department of Pharmaceutical Technology, School of Pharmacy,
Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
b School of Pharmacy and Biomedical Sciences, St Michael's Building,
White Swan Road, Portsmouth PO1 2DT, UK
[e-mail]
1.1 INTRODUCTION
Carbon nanotubes (CNTs) are allotropes of carbon that are composed
entirely of carbon atoms arranged into a series of condensed benzene rings,
known as graphene sheets, “rolled” into a cylindrical structure. They belong
to the family of fullerenes, the third allotrope of carbon after graphite and
diamond. 1-3
CNTs can be classiied into two categories according to their structure: (i)
single-walled carbon nanotubes (SWCNTs), comprising a single cylindrical
graphene layer capped at both ends in a hemispherical arrangement of carbon
networks, and (ii) multi-walled carbon nanotubes (MWCNTs), consisting
of numerous concentric cylinders of graphene sheets. SWCNTs have outer
diameters ranging from 1.0 to 3.0 nm and inner diameters ranging from 0.6
to 2.4 nm, whereas for MWCNTs, outer diameters range from 2.5 to 100 nm
and inner diameters range from 1.5 to 15 nm. MWCNTs can consist of varying
amounts of concentric SWCNT layers, which are separated by a distance of
approximately 0.34 nm (Fig.1.1) . 4,5
CNTs are highly versatile because of their physicochemical features. They
possess ordered structures with a high ratio of length to diameter (aspect
ratio) and are ultra-light-weight.