Localized to long-range conductivity in polyaniline/magnetite nanocomposites followed by dielectric relaxation spectroscopy

Localized to long-range conductivity in polyaniline/magnetite nanocomposites followed by dielectric relaxation spectroscopy

Polyaniline (PAni) and magnetite (Fe 3 O 4 ) are well-known semiconducting materials with quite different conduction mechanisms: localized conductivity for magnetite and long-range conductivity for PAni. Fe 3 O 4 nanoparticles were used to polymerize aniline, forming a PAni/Fe 3 O 4 hybrid nanocompo...

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Bibliographic Details
Published in:Colloid and polymer science Vol. 293; no. 6; pp. 1675 - 1683
Main Authors: de Araújo, A. C. Vaz, de Oliveira, R. José, Alves, S., de Azevedo, W. Mendes
Format: Journal Article
Language:English
Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-06-2015
Springer Nature B.V
Subjects:
Characterization and Evaluation of Materials
Chemistry
Chemistry and Materials Science
Complex Fluids and Microfluidics
Food Science
Nanotechnology and Microengineering
Original Contribution
Physical Chemistry
Polymer Sciences
Soft and Granular Matter
Dielectric relaxation spectroscopy
nanoparticles
Polyaniline
nanocomposites
PAni/Fe
Fe
O
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Summary:Polyaniline (PAni) and magnetite (Fe 3 O 4 ) are well-known semiconducting materials with quite different conduction mechanisms: localized conductivity for magnetite and long-range conductivity for PAni. Fe 3 O 4 nanoparticles were used to polymerize aniline, forming a PAni/Fe 3 O 4 hybrid nanocomposite. The microstructural evolution and the electrical behavior of this nanocomposite were studied by dielectric relaxation spectroscopy (DRS). Albeit being a powerful technique to probe the electrical properties of materials, DRS has not yet been used to characterize such system in reasonable detail. The dc conductivity for pure magnetite was approximately 10 −6  S cm −1 , while the values for the PAni/Fe 3 O 4 nanocomposites were 1 order of magnitude higher. The Fe 3 O 4 nanoparticles behave like a material composed of packed grains, with substantial grain volume and grain boundary effects, leading to different dielectric responses at high and low frequencies. The partial consumption of Fe 3 O 4 during polymerization results in smaller magnetic crystals embedded within the PAni matrix, and the decreased number of crystallite interfaces leads to lower interfacial resistance. Hence, the formation of PAni causes a decrease in the material’s volume resistance and imparts long-range conduction pathways on the material. This work shows the feasibility of using DRS to follow the microstructural evolution of a nanocomposite and changes in its conduction mechanisms, which are essential for the proper development of novel materials and devices.
ISSN:0303-402X
1435-1536
DOI:10.1007/s00396-015-3532-9