Mössbauer spectroscopy studies of selected conducting polypyrroles

Abstract

Polypyrrole obtained by chemical oxidation of pyrrole in ethanol–water solution containing FeCl3 can be reduced chemically in Na+Naph−/THF solution and then reoxidized with FeCl3, SnCl4, and SbCl5. 57Fe and 119Sn Mössbauer spectra of the reaction products show only one type of iron and tin with Mössbauer parameters characteristic of FeCl−4 and SnCl−5. In the case of the oxidation with SbCl5, two nonequivalent antimony nuclei have been detected by 121Sb. The calculated isomer shift and quadrupole splitting values are consistent with SbCl−6 and SbCl3. The resonant absorption in all three systems studied is strongly temperature dependent and can be observed only at temperatures significantly lower than RT. This behavior indicates a low Mössbauer lattice temperature and an extremely loose bonding between the inserted anions and polymer chains.

In situ generation of a high-performance Pd-polypyrrole composite with multi-functional catalytic properties

“…40 Chemical synthesis of polypyrrole has a long history. Polypyrrole has been prepared by the oxidation of the monomer ( pyrrole) using ammonium persulfate (APS), 41 aqueous or anhydrous FeCl 3 42,43 as well as other salts of iron (III) and copper (II) 44,45 as chemical oxidants. In the present work, Pd-acetate was used as the oxidant for the synthesis of polypyrrole.…”

Polypyrrole nanoparticles as a thermal transducer of NIR radiation in hot-melt adhesives

“…Kanazawa 18 carried out the precipitation polymerizations of Py in a variety of non-aqueous but semi-polar solvents, such as acetonitrile. Pron et al 19 described an aqueous (aqueous/ethanol)-based synthesis, using FeCl 3 as initiator, which was subsequently used by Bjorklund and Liedberg 20 and by Armes and coworkers 21,22 to obtain colloidal forms of PPy. Bjorklund and Liedberg 20 carried out the polymerization of Py in aqueous solutions of methylcellulose.…”

Chemically polymerized polypyrrole for on-chip concentration of volatile breath metabolites

“…Chemically polymerized pyrrole has reported electrical conductivity from 5 to 200 S/cm [4, 35-37] whereas electropolymerized pyrrole range from 20-500 S/cm [1, 38] and up to 1000 S/cm for elongated films [39]. Resistivity measurements of the prepared polypyrrole films and bulk polypyrrole were attempted with a multimeter and a four-point probe as described above.…”