Direct patterning of conductive water-soluble polyaniline for thin-film organic electronics

We report a simple and low-cost technique for directly patterning conductive water-soluble polyaniline. This technique exploits the hydrophilic nature of polyaniline that was synthesized on a polymer acid template. To create conductive features, aqueous polyaniline solutions are directly spun cast onto substrates previously patterned with hydrophilic and hydrophobic regions. Polyaniline selectively adsorbs in the hydrophilic regions thereby resulting in features as small as 5 μm with an average conductivity of 0.3 S/cm over large areas. Polyaniline contacts for thin-film transistors were fabricated; such devices show on characteristics that are quantitatively similar to those of reference devices with gold electrodes.