Functionalization of carbon nanotubes by polymers using grafting to methods

The huge research effort devoted to the chemical modification of CNTs by grafted macromolecules is driven by the need to enhance their affinity for a variety of environments, a necessary step for designing advanced nanomaterials. This chapter aims at reviewing the until now investigated “grafting to” methods used for the surface modification of carbon nanotubes (CNTs) by polymers of various functionalities. Two major strategies are emphasized on the basis of the number of needed modification steps. The first technique consists in functionalizing the CNTs surface to promote in a second step the covalent anchoring of polymer chains bearing complementary reactive groups either at one chain-end or along the chain. The second approach is straightforward as result of the ability of the selected polymer to add directly onto the sp2 carbons of the CNTs surface. The major advantage of the “grafting onto” techniques is that the molecular characteristics (molecular weight, polydispersity, functionality,…) of the polymers can be tailored prior to the grafting reaction. Moreover, when using the proper controlled or living polymerization techniques and grafting conditions, polymers of well-defined architecture, functionality and properties can be easily anchored to the CNTs surface, which makes the “on-demand” tuning of the chemical properties of CNTs possible.