Immobilization of tetra-tert-butylphthalocyanines on carbon nanotubes: a first step towards the development of new nanomaterials

Non-covalent functionalization of carbon nanotubes (CNTs) is of paramount importance for developing new nanomaterials without destruction of the electrical properties of the CNTs. In this paper, we report a simple approach to immobilize tetra-tert-butylphthalocyanines (tBuPcs) on CNTs. The immobilization results from the pi-pi interaction, rather than a covalent interaction, between the CNTs and the conjugated tBuPc molecules. It is found that CNTs can fade the color of chloroform solutions of tBuPcs. There is an adsorption threshold of the CNTs for tBuPcs in our case. The more the relative weight of tBuPcs as compared with CNTs, the more slowly CNTs fade the solution, and the bluish green color of the tBuPcs cannot be decolorized when the weight ratio of tBuPcs to CNTs is larger than 1.5. The versatility of this simple method can be extended to other members, with the desired properties, of the Pc family, and constitutes a first step in the development of new Pc-based nanomaterials.