Layer-by-layer (LbL) assembly was used to produce highly conductive thin filmswith carbon black (CB) and polyelectrolytes. The effects of sonication and pHadjustmentof the deposition mixtures on the conductivity and transparency of depositedfilms were studied. Drying temperature was also evaluated with regard to thin filmresistance. Sonication and oven drying at 70oC produced films with the lowest sheetresistance (~ 1500 ????/sq), which corresponds to a bulk resistivity of 0.2 ??????????cm for a 14-bilayer film that is 1.3 ????m thick. Increasing the pH of the PAA-stabilized mixture anddecreasing the pH of the PEI-stabilized mixture resulted in films with 70% transparencydue to thinner deposition from increased polymer charge density. Varying the numberof bilayers allows both sheet resistance and optical transparency to be tailored over abroad range.Variation of deposition mixture composition led to further reduction of sheetresistance per bilayer. A 14 bilayer film, made from mixtures of 0.25wt% carbon blackin 0.05wt% PAA and plain 0.1wt% PEI, was found to have a sheet resistance ofapproximately 325 ????/sq. Bulk resistivity was not improved due to the film being 8 ????mthick, but this combination of small thickness and low resistance is an order of magnitude better than carbon black filled composites made via traditional melt orsolution processing. Applications for this technology lie in the areas of flexibleelectronics, electrostatic charge dissipation, and electromagnetic interference shielding.
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