Inkjet printable polyaniline-gold dispersions

Inkjet printable polyaniline-gold (PANI-Au) hybrid dispersions were synthesised using gold salt as oxidant to simultaneously induce chemical oxidative polymerisation of aniline and reduction of HAuCl4 in bulk aqueous solution. By varying the amount of HAuCl4 used for the polymerisation, the size, morphology and population of the resulting gold particles embedded within the polymer were controllable. It was shown however, that the metallic gold particles contained within the resulting dispersions did not appear to affect the bulk conductivity of PANI, but rather that by varying the amount of HAuCl4 used, both the quality and printability of the resulting PANI-Au dispersion could be affected. PANI-Au synthesised using a ratio of 1:0.25 aniline:HAuCl4 was shown to be optimum as it resulted in dispersions with high polymer conjugation lengths and doping levels, as well as high conductivity and well-defined electrochemistry. This hybrid material was shown to be highly processable, and inkjet printing of this material was demonstrated on flexible substrate which resulted in high quality, printed films.