Ba. Lunn et al., DETERMINATION OF THE THERMAL-CONDUCTIVITY OF POLYPYRROLE OVER THE TEMPERATURE-RANGE 280-K-335-K, Journal of Materials Science, 28(18), 1993, pp. 5092-5098
Samples of polypyrrole were synthesised under galvanostatic conditions
to produce films possessing a range of electrical conductivity from 1
0(-3) to 1 0 S cm-1. The electrical and thermal conductivity of these
films has been determined between 280 and 335 K. The electrical conduc
tivity was measured using a four probe technique calibrated against AS
TM D4496-87. Thermal conductivity was determined from measurements of
thermal diffusivity, specific heat and density. Thermal diffusivity wa
s determined. using a modified a.c. calorimetry technique, while diffe
rential scanning calorimetry (DSC) was used to determine specific heat
. The polymer's density was measured using Archimedes' principle. The
results were used to calculate the Lorenz number of polypyrrole.-A com
parison of the predicted behaviour and experimental results was made.
Thermal conductivity is found to be large compared to that predicted f
rom the electrical conductivity measurements on low conductivity films
. Molecular vibration effects are found to be non-trivial and experime
ntal means for measuring their contribution are mentioned. While polyp
yrrole has been regarded as a ''synthetic metal'' the thermal conducti
vity results show this classification is wrong.