Limits...
Effect of the carbon nanotube surface characteristics on the conductivity and dielectric constant of carbon nanotube/poly(vinylidene fluoride) composites.

Carabineiro SA, Pereira MF, Pereira JN, Caparros C, Sencadas V, Lanceros-Mendez S - Nanoscale Res Lett (2011)

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: 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. sonia.carabineiro@fe.up.pt.

ABSTRACT
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.

No MeSH data available.


Electrical response of the PVDF/CNT nanocomposites: (a) Volume resistivity of the PVDF/CNT nanocomposites for the different functionalized CNTs; (b) dielectric constant at room temperature and 10 kHz for the PVDF/CNT original composites.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211369&req=5

Figure 4: Electrical response of the PVDF/CNT nanocomposites: (a) Volume resistivity of the PVDF/CNT nanocomposites for the different functionalized CNTs; (b) dielectric constant at room temperature and 10 kHz for the PVDF/CNT original composites.

Mentions: CNT agglomerates are nevertheless more often observed for the CNTox composites samples, especially for the ones treated at the highest temperatures. With respect to the electrical properties, oxidation reduces the composite conductivity for a given concentration and shifts the percolation threshold to higher concentrations (Figure 4). This behavior is mainly due to the reduction of the surface conductivity of the CNTs due to the oxidation process [8], and is similar for all the functionalized composites. Further, the increase of surface area due to the functionalization treatment certainly causes surface defects on the CNTs that also reduced electrical conductivity. The increase of agglomerations for the treated samples should not have, on the other hand, a large influence in the electrical response [8]. A change of several orders of magnitude of the electrical resistivity with increasing CNTs concentration was observed for all samples, indicating a percolative behavior of the nanocomposites. In general, both in surface (not shown) and in bulk resistivity (Figure 4a), the percolation threshold appears between 0.2 wt.% for the original CNT samples and shifts to 0.5 wt.% CNTs for the functionalized nanocomposites.


Effect of the carbon nanotube surface characteristics on the conductivity and dielectric constant of carbon nanotube/poly(vinylidene fluoride) composites.

Carabineiro SA, Pereira MF, Pereira JN, Caparros C, Sencadas V, Lanceros-Mendez S - Nanoscale Res Lett (2011)

Electrical response of the PVDF/CNT nanocomposites: (a) Volume resistivity of the PVDF/CNT nanocomposites for the different functionalized CNTs; (b) dielectric constant at room temperature and 10 kHz for the PVDF/CNT original composites.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211369&req=5

Figure 4: Electrical response of the PVDF/CNT nanocomposites: (a) Volume resistivity of the PVDF/CNT nanocomposites for the different functionalized CNTs; (b) dielectric constant at room temperature and 10 kHz for the PVDF/CNT original composites.
Mentions: CNT agglomerates are nevertheless more often observed for the CNTox composites samples, especially for the ones treated at the highest temperatures. With respect to the electrical properties, oxidation reduces the composite conductivity for a given concentration and shifts the percolation threshold to higher concentrations (Figure 4). This behavior is mainly due to the reduction of the surface conductivity of the CNTs due to the oxidation process [8], and is similar for all the functionalized composites. Further, the increase of surface area due to the functionalization treatment certainly causes surface defects on the CNTs that also reduced electrical conductivity. The increase of agglomerations for the treated samples should not have, on the other hand, a large influence in the electrical response [8]. A change of several orders of magnitude of the electrical resistivity with increasing CNTs concentration was observed for all samples, indicating a percolative behavior of the nanocomposites. In general, both in surface (not shown) and in bulk resistivity (Figure 4a), the percolation threshold appears between 0.2 wt.% for the original CNT samples and shifts to 0.5 wt.% CNTs for the functionalized nanocomposites.

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: 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. sonia.carabineiro@fe.up.pt.

ABSTRACT
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.

No MeSH data available.