Temperature dependence of the resistivity in polymer–conducting-carbon-black composites

Abstract

The electrical dc resistivity of variously prepared polymerconducting-carbon-black composites has been studied over a wide temperature range (4.2 -300 K). For the different composites, the resistivity follows a lnp-T law over the whole temperature range, with the a parameter, varying between -, ' &a& -', determined by the carbon-black concentration and the dispersion in the carbon grain sizes. The experimental facts can be understood on the basis of a critical-pathmethod analysis for hopping conduction developed for granular disordered metallic systems.

Piezoresistive Materials from Directed Shear-Induced Assembly of Graphite Nanosheets in Polyethylene

“…[39,40] If conduction is dominated by tunneling through the insulating gaps separating the conductive particles, the conductance G ij between two conducting grains i and j is expressed by Equation 1 [41,42] …”

Insulator coated metal nanoparticles with a core/shell geometry exhibit a temperature sensitivity similar to advanced spinels

“…The corresponding experimentally determined values of n depend mainly on the conducting phase material and its characteristic dimension [44]. In the case of polymers filled with carbon black n varies in the range of 0.5-0.75 [45,46]. Carbon as a matrix filled with individual, non-touching metal grains affords values of n between 0.5 and 0.25 and includes metallic germanium in carbon [44], aluminum in germanium [47] and X/SiO 2 or X/Al 2 O 3 , where X = Ni, Pt, Au [48] and even metallic vanadium glasses [49].…”

Temperature and magnetic-field dependence of the resistivity of carbon-black polymer composites

“…The value of the critical exponent (t) is slightly larger than the theoretical value 3 for a 3D system (tϭ1.6-2.0 depending on the network geometry͒ but close to the values reported by others. 5,6,10 The small value of p c suggests that the solution technique is useful to obtain a small percolation threshold.…”

“…A temperature dependence of the resistivity with nϾ1/2 and a small value of T 0 above 4.2 K have been reported by others for CB systems. 5,6 The authors of Ref. 6 interpreted their results by assuming superlocalization of the electronic states in the fractal CB polymer.…”

“…5,6 In the conventional VRH theory 3,7,8 the temperature dependence of the resistivity follows an expression of the form (T)ϳexp(T 0 /T) n . In three-dimensional ͑3D͒ systems such as ours nϭ1/4 and the value of T 0 is usually large compared to the measured temperature range.…”