Influence to the spatial conformation of NT functionalized with different polymers according to their electronic distribution

HERNÁN GARATE; ALEJANDRO DE FALCO; S. MORENO; MIRTA FASCIO; SILVIA GOYANES; D'ACCORSO NORMA B.

Buenos Aires, Argentina

Congreso; At the Frontiers of Condensed Matter V; 2010

Comisión Nacional de energía Atómica

The purpose of this work is to study the influence to the spatial conformation of a polymer grafted onto multi-walled carbon nanotubes (MWCNT) according to the differing electronic distribution of the polymer’s repetitive unit. It is known that polymers with aromatic rings interact with the nanotube through pi-pi staking interactions, tending to wrap the MWCNT and propitiating a better dispersion of them in a solvent with affinity to the polymer or in the polymer itself, leading to a composite material with well dispersed MWCNT. On the other hand, if trying to anchor the MWNT to one of the phases of a block copolymer, it would be more efficient to have the MWCNT functionalized with a polymer that doesn’t wrap the nanotube, thus allowing the anchorage by means of inter-diffusion of the polymer into the block with more affinity to it. In this work, we made a graft-from functionalization using as monomers: 4-vinylpyridine (monomer with an aromatic substituent) and acrylonitrile (monomer with a non aromatic, where the substituent is a nitrile group). The functionalization efficiency was studied by spectroscopic and thermal technique. The spacial conformations of the polymer around carbon nanotubes were studied by high resolution transmission electron microscopy (HRTEM). It was seen, in both cases, polymer wrapping the NT. However, for polymers with aromatic rings, this effect is predominant, while with polyacrylonitrile derivates what can be seen is polymer wrapped onto itself and bound to the MWCNT’s wall.