Biology Reference
In-Depth Information
provides a close proximity of the two materials that facilitate their
electronic communication.
Besides metal NPs, carbon micro and nanoparticles as well as
carbon nanotubes are usually used as fillers in composites for elec-
trochemicaltransducers. Thefollowingsectionfocusesontheprop-
erties and main issues of carbon-polymer conducting composites
based on nonconductingbindersand polymers.
3.3 Carbon Composites
3.3.1
Carbon-Based Materials as Conductive
Fillers in Composites
Carbon is an ideal choice as composite filler due to its high chem-
ical inertness, wide range of working potentials, low electrical
resistance, and low residual currents. The extraordinary ability of
carbon to combine with itself and other chemical elements in dif-
ferent ways is the basis of organic chemistry. As a consequence,
there is a rich diversity of structural forms of solid carbon because
it can exist as any of the several allotropes. It is found abundantly
in nature as coal, a natural graphite, and also in much less abundant
form as diamond. Engineered carbons [57] are the product of the
carbonization process of a carbon-containing material, conducted
in an oxygen-free atmosphere. Depending on the starting precur-
sormaterial(hydrocarbongases,petroleum-derivedproducts,coals,
polymers,biomass),theproductofacarbonizationprocesswillhave
different properties, including the adsorption capability. Traditional
engineeredcarbonscantakemanyforms,suchascoke,graphite,car-
bon and graphite fiber, carbon monoliths, glassy carbon (GC), car-
bon black, carbon film, and diamond-like film [57]. The discovery
of nanostructured carbon-based materials added a new dimension
to the knowledge of carbon science. The first TEM evidence for the
tubularnatureofsomenanosizedcarbonfilaments,thatis,ofcarbon
nanotubes (MWCNT, multiwalled carbon nanotubes) was reported
in1952byRadushkevichandLukyanovich[58].Thesubsequentdis-
covery in the “nano” era of “fullereness” [59] has also impacted the
carbonscience.Finally,thegrowingofSWCNTswasfirstreportedin
