Effect of the carbon nanotube surface characteristics on the conductivity and dielectric constant of carbon nanotube/poly(vinylidene fluoride) composites
1 Universidade do Porto, Faculdade de Engenharia, Laboratório de Catálise e Materiais (LCM), LSRE/LCM - Laboratório Associado, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
2 Centro/Departamento de Física da Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
Nanoscale Research Letters 2011, 6:302 doi:10.1186/1556-276X-6-302Published: 7 April 2011
Commercial multi-walled carbon nanotubes (CNT) were functionalized by oxidation with HNO3, to introduce oxygen-containing surface groups, and by thermal treatments at different temperatures for their selective removal. The obtained samples were characterized by adsorption of N2 at -196°C, temperature-programmed desorption and determination of pH at the point of zero charge. CNT/poly(vinylidene fluoride) composites were prepared using the above CNT samples, with different filler fractions up to 1 wt%. It was found that oxidation reduced composite conductivity for a given concentration, shifted the percolation threshold to higher concentrations, and had no significant effect in the dielectric response.