Functionalized SWCNT

Pristine carbon nanotubes (CNTs) are insoluble in many liquids such as water, polymer resins, and most solvents. This means they are difficult to evenly disperse in a liquid matrix such as epoxies and other polymers, complicating efforts to utilize CNTs' outstanding physical properties in the manufacture of nanocomposite materials, as well as in other practical nanotechnology applications which require preparation of uniform mixtures of CNTs with many different organic, inorganic, and polymeric materials.

To make nanotubes more easily dispersible in liquids, it is necessary to physically or chemically attach certain molecules, or functional groups, to their sidewalls without significantly changing the nanotubes' desirable properties. This process is called functionalization.

Single-walled CNTs arguably are the ultimate biosensor among nanoscale semiconducting materials not only for their size – which is directly comparable to the size of single biomolecules – but also because their low charge-carrier density is directly comparable to the surface charge density of proteins. Furthermore, a single-walled CNT (SWCNT) consists solely of surface such that every single carbon atom is in direct contact with the environment, allowing optimal interaction with nearby biomolecules..

Generally, the smart functionalization of CNTs with chemically, biochemically, or electrochemically functional materials could provide a straightforward approach to the development of nanostructured electrochemical devices with promising properties and striking applications.

The strategies for the functionalization of the CNTs have strongly relied on the interactions inherent to the CNTs and the materials, which are mainly dependent on the structural and chemical properties of the materials.