Abstract
The conductivity and the dielectric constant of the "emeraldine" form of polyaniline is studied in a wide range of frequency (dc, 101-105 Hz, 6.5×109 Hz), temperature (20K-340K) and protonation level (x ≡[C1]/[N] =0.0-0.5). Two distinct behaviors are observed: Firstly, for low protonation (x ≤ 0.13), hopping of charges between polarons and bipolarons leads to dipolar relaxation (ε{lunate}RF(T)). Oscillation of polarons around pinning centers is suggested to be responsible for the high frequency dielectric constant of low protonated samples. Secondly, for intermediate to highly protonated samples (x > 0.22), the presence of "metallic islands" is apparent. Oscillation of charge carriers within the coherence length contributes to ε{lunate}μω(T=0). The intrinsic conductivity within the islands is estimated to be of the order of 250 S/cm. The T-dependence of the dielectric constant indicates an increase of the coherence length with increasing temperature. The role of localization and the nature of "textured metallic islands" are discussed.
Original language | English (US) |
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Pages (from-to) | 409-416 |
Number of pages | 8 |
Journal | Synthetic Metals |
Volume | 29 |
Issue number | 1 |
DOIs | |
State | Published - Mar 7 1989 |
Externally published | Yes |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry