AN OBTAINING METHOD FOR CARBON NANOTUBES WITH MODIFIED SURFACE

Abstract

It is well-known the fact that carbon nanotubes (CNTs) contain carbon atoms in different hybridization states (sp³ and sp²), that generates complex structures (diamond and graphite respectively). These multiple connections generate strong interaction of forces between particular CNTs, that means Van der Waals forces and also π-π type those immediate result in the agglomerates obtaining and, singularizing the composite materials, the first effect is clusters generation process. The physical-chemical properties of nanocomposite materials are influenced by the appropriate CNTs dispersion obtaining in the matrix. This fact is efficiently obtained when the interactions energy between CNTs themselves is lower than the dispersion energy cumulated with the interactions energy between CNTs and the matrix. The dispersion energy considers CNTs blending techniques inside the matrix and the interactions energy between CNTs and the matrix supposes the chemical bond obtaining and physical-chemical interactions between CNTs and the matrix. The aim of this paper is to present some techniques of oxidative chemical treatment in order to obtain a CNTs functionalized surface as well as some techniques of coating with ceramic materials molecular layers in order to increase the chemical bond energy and the physical-chemical interactions between CNTs and the matrix. We used simple treatment methods of CNTs in acidic solutions (HNO₃ – H₂SO₄) and basic solutions (NH₃) having hydrogen peroxide as the oxidant agent (H₂O₂ 30%). CNTs coating process with ceramic materials was made by using the precipitation method of their components (Fe₂O₃) from the supersaturated aqueous solutions.