Layer-by-layer (LbL) assembly was used to produce highly conductive thin films
with carbon black (CB) and polyelectrolytes. The effects of sonication and pHadjustment
of the deposition mixtures on the conductivity and transparency of deposited
films were studied. Drying temperature was also evaluated with regard to thin film
resistance. Sonication and oven drying at 70oC produced films with the lowest sheet
resistance (~ 1500 é/sq), which corresponds to a bulk resistivity of 0.2 éâÂÂ
cm for a 14-
bilayer film that is 1.3 üm thick. Increasing the pH of the PAA-stabilized mixture and
decreasing the pH of the PEI-stabilized mixture resulted in films with 70% transparency
due to thinner deposition from increased polymer charge density. Varying the number
of bilayers allows both sheet resistance and optical transparency to be tailored over a
broad range.
Variation of deposition mixture composition led to further reduction of sheet
resistance per bilayer. A 14 bilayer film, made from mixtures of 0.25wt% carbon black
in 0.05wt% PAA and plain 0.1wt% PEI, was found to have a sheet resistance of
approximately 325 é/sq. Bulk resistivity was not improved due to the film being 8 üm
thick, but this combination of small thickness and low resistance is an order of magnitude better than carbon black filled composites made via traditional melt or
solution processing. Applications for this technology lie in the areas of flexible
electronics, electrostatic charge dissipation, and electromagnetic interference shielding.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/5979 |
| Date | 17 September 2007 |
| Creators | Jan, Chien Sy Jason |
| Contributors | Grunlan, Jaime C. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Electronic Thesis, text |
| Format | 4392912 bytes, electronic, application/pdf, born digital |
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