An emulsion process has been developed for the direct synthesis of the emeraldine salt of polyaniline (PANI) that is soluble in organic solvents. The process entails formation of emulsion particles with a mean hydrodynamic diameter of 150 nm and consisting of a water-soluble organic solvent (e.g., 2-butoxyethanol), a water-insoluble organic acid (e.g., dinonylnaphthalenesulfonic acid), aniline, and water. Aniline is protonated by the organic acid to form a salt which partitions into the organic phase. As oxidant (ammonium peroxydisulfate) is added to the reaction mixture, PANI intermediates are formed in the organic phase. As the reaction proceeds, the emulsion flocculates, forming a two-phase system. The reaction features an induction period followed by an exothermic polymerization, at which time soluble PANI forms in the organic phase. The reaction progress is conveniently monitored by temperature, pH, and open circuit potential. When dinonylnaphthalenesulfonic acid (DNNSA) is employed as the organic ac...