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Characterization of the electrical properties of polyaniline in the temperature range 30-450 K
Dissertation (MSc (Physics))--University of Pretoria, 2006.
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University of Pretoria
2013
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| _version_ | 1867613586939969536 |
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| access_status_str | Open Access |
| author2 | Goodman, S.A. (Stewart Alexander) |
| author_browse | Goodman, S.A. (Stewart Alexander) |
| author_facet | Goodman, S.A. (Stewart Alexander) |
| collection | Thesis |
| dc_rights_str_mv | © 2001, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc (Physics))--University of Pretoria, 2006. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/29755 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:38:30.789Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/29755 Characterization of the electrical properties of polyaniline in the temperature range 30-450 K Goodman, S.A. (Stewart Alexander) upetd@up.ac.za Mzenda, Venantio Marovha Conducting polymers characterization Charge transfer devices electronics UCTD Dissertation (MSc (Physics))--University of Pretoria, 2006. Despite the poor understanding of charge transfer in conducting polymers, conducting-polymer-based devices have achieved considerable commercial success. This success is based largely on the reproducibility of the measurable properties. It is the purpose of this study to further clarify charge transfer characteristics of conducting polymers under varying conditions. We studied a conducting polymer called polyaniline. Polyaniline was available in its doped conducting form called emeraldine salt and in its undoped form called emeraldine base. Three types of polyaniline were studies, electrosynthesized (doped by HCI), chemically synthesized (doped by HCI) and commercial polyaniline obtained from Adlrich Company and doped by camphor sulfonic acid. Initially we investigated whether charge transfer was ionic or electronic by observing the change in resistance with time for a fixed applied current. It was concluded that condition in this material is electronic. Electrical measurements were obtained using the four-point probe and the Montgomery methods. The samples investigated were in pellet and film forms. We investigated charge transfer over the temperature regime 30-450 K by applying the following methods: scanning electron microscopy to investigate the surfaces of pellet and film samples, Fourier transform infrared spectroscopy and Raman spectroscopy to investigate the effect of annealing on the molecular structure of the polymer and thermal analysis to investigate the loss of substances from the polymer as a result of the annealing process. The conductivity of the material was also analyzed over the entire temperature regime. The following were observed: • Conductivity in polyaniline is governed my monomer units. • The decrease in conductivity with increase annealing temperature is related to moisture loss, loss of dopant ions and polymer degradation. • The variable range hopping model in three dimensions, satisfactorily describes charge transfer mechanism in polyaniline. • Conductivity in polyaniline is temperature activated. • Conductivity varies with position on the sample surface. • The effect of pellet pressing pressure to conductivity is negligible. • Current-voltage characteristics for polyaniline exhibit non-ohmic behavior at high current values, (>0.2 mA for T <80 K), applied between the current probes of a four-point probe measuring instrument. Physics unrestricted 2013-09-07T16:31:14Z 2005-11-30 2013-09-07T16:31:14Z 2002-04-21 2006-11-30 2005-11-24 Dissertation Mzenda, VM 2001, Characterization of the electrical properties of polyaniline in the temperature range 30-450 K, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/29755 > H149/ag http://hdl.handle.net/2263/29755 http://upetd.up.ac.za/thesis/available/etd-11242005-144306/ © 2001, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf application/pdf application/pdf application/pdf University of Pretoria |
| spellingShingle | Conducting polymers characterization Charge transfer devices electronics UCTD Characterization of the electrical properties of polyaniline in the temperature range 30-450 K |
| title | Characterization of the electrical properties of polyaniline in the temperature range 30-450 K |
| title_full | Characterization of the electrical properties of polyaniline in the temperature range 30-450 K |
| title_fullStr | Characterization of the electrical properties of polyaniline in the temperature range 30-450 K |
| title_full_unstemmed | Characterization of the electrical properties of polyaniline in the temperature range 30-450 K |
| title_short | Characterization of the electrical properties of polyaniline in the temperature range 30-450 K |
| title_sort | characterization of the electrical properties of polyaniline in the temperature range 30 450 k |
| topic | Conducting polymers characterization Charge transfer devices electronics UCTD |
| url | http://hdl.handle.net/2263/29755 http://upetd.up.ac.za/thesis/available/etd-11242005-144306/ |