Polypyrrole–silver composites prepared by the reduction of silver ions with polypyrrole nanotubes

Abstract

Polypyrrole nanotubes were prepared by the oxidation of pyrrole with iron(III) chloride in the presence of methyl orange. They were subsequently used for the reduction of silver ions to silver nanoparticles. The nanotubular form of polypyrrole is compared with the classical globular morphology in its ability to reduce silver ions. Both polypyrrole salts and bases were used in the experiments. The content of metallic silver in the resulting composite, determined by thermogravimetric analysis, was 21-31 wt%.Elemental composition is also discussed on the basis of energy-dispersive X-ray spectroscopy. Contrary to the expectation, the conductivity of polypyrrole nanotubes in salt form, 35.7 S cm À1 , was reduced to 20.9 S cm À1 after the incorporation of silver. The presence of silver had generally little effect on the conductivity. The temperature dependence of conductivity reveals that the composites maintain the semiconducting character of polypyrrole and their conductivity increased with increasing temperature. The conductivity of the composites surprisingly increased when the samples were placed in vacuo.

Flexible Thermoelectric Composite Films of Polypyrrole Nanotubes Coated Paper

“…As a 1D material, polypyrrole nanotubes (PPy-NTs) have a higher electrical conductivity when compared to PPy nanoparticles [8,9]; therefore, it is beneficial to enhancing its TE properties. For example, a ZT value of 5.71 × 10 −4 (power factor of 0.31 µW·m −1 ·K −2 ) at 310 K was reported for the PPy-NT films [10].…”

The deposition of globular polypyrrole and polypyrrole nanotubes on cotton textile

“…The fact that we deal with nanotubes (Fig. 3c), and not with nanofibres, has earlier been proved by transmission electron microscopy [54,56].…”

“…Despite the fact that the conductivity of globular polypyrrole powder, 0.012 S cm −1 , is much lower than that of nanotubular polypyrrole pellet, 35 S cm -1 [54], the conductivity of the cotton coated with these polymer forms is much lower and the order is reversed (Table 1). This is due to the thicker polypyrrole coating with globular form and thinner with nanotubular one.…”

“…When pyrrole is oxidized in the presence of methyl orange, polypyrrole nanotubes are produced instead of ordinary globular morphology [54][55][56][57]. The nanotubes are of interest not only because of their nanostructure but also for high conductivity, 40-70 S cm −1 [56].…”

Thermal Properties of Conducting Polypyrrole Nanotubes

“…The deprotonation of PPy salt to PPy base was made by the suspension of PPy salt in excess of 1 M ammonium hydroxide [22]. The deprotonation process results in the decrease of chloride counterions content in the polymer structure.…”