Influence of aspect ratio of carbon nanotube on percolation threshold in ferroelectric polymer nanocomposite

Multiwall carbon nanotube (MWNT) with different aspect ratio (AR) was dispersed into ferroelectric polyvinylidene fluoride (PVDF) to fabricate the MWNT/PVDF nanocomposites. An increase of dielectric constant with increasing the AR value was observed in the MWNT/PVDF composites. Meanwhile, the result showed that the change of percolation threshold displayed the same rule with that of critical exponent, and both of them increased with increase of AR in some extent, which provides an effective and simple way to describe the dielectric transition of practical composites in the neighborhood of percolation threshold with the scaling theory. (C) 2007 American Institute of Physics.