Conductive nano-composites have the potential to replace traditional conductive materials due to the enhanced mechanical, electrical and chemical properties that lend themselves to a plethora of applications. In this work, conductive nano-composites of poly (3,4-ethylenedioxythiophene)-poly(styrenesulfonate) with multi-walled carbon nanotubes (PEDOT:PSS/MWCNT) and PEDOT:PSS with silver nanowires (PEDOT:PSS/Ag NW) were prepared, characterized and tested for gas sensing and lighting applications. Carbon nanotubes were functionalized covalently with carboxylic acid and non-covalently with surfactant and polymer molecules. The functionalized nanotubes were mixed with PEDOT:PSS at different concentrations and printed using inkjet printing techniques. The effect of the concentration of these nanotubes on the electrical properties of the nano-composite samples was investigated. The results show that the electrical conductivity of the printed structures strongly depends on the concentration of the nanotubes in the sample. Furthermore. the electrical properties strongly depend on the wetting of the substrate and by controlling the wettability, the conductivity of the nano-composite samples can be improved. Based on polymer conductivity, the electrical conductivity of the composite fi lm can be improved or degraded by orders of magnitude with the incorporation of the MWCNT. Moreover, electrical measurements show strong correlation between the conductivity of the carbon nanotube nehvork and the resulting nano-composite films. Excellent alignment of the nanotubes with improvement in the conductivity of the printed sample was also achieved using a novel and simple methodology. Carbon nanotube gas sensors were fully printed on flexible substrates and tested as ethanol sensors. The performance shows significant enhancement in the sensitivity of the PEDOT:PSSIMWCNT based sensor, in comparison to the pristine nanotubes and pristine polymer based sensors with enhancement factor greater than 2.5. Moreover, a remarkable improvement in the response and recovery time of the sensor after polymer functionalization is also reported.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:606808 |
| Date | January 2013 |
| Creators | Alshammari, Abdullah S. |
| Publisher | University of Surrey |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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