Columbian Chemical Company's world patent published on December 4, 2003 reveals a sulfonic acid conductor polymer-grafted carbon material. The manufacturing process is to oxidatively polymerize heteroatom-containing conductor polymer monomers in carbon materials and then sulfonate and graft them. This method can also further metallize the polymer-grafted carbon materials. Carbonaceous materials can be carbon black, graphite, nanocarbon or fullerenes, etc. The polymers are polyaniline, polypyrrole, etc. Its proton conductivity is 8.9×10-2S/cm (tested by Nafion-sulfonic acid polyaniline).
Many domestic patents adopt similar methods. For example, Tsinghua University's Chinese patent CN1476113, published in June 2003, adds aromatic heterocyclic polymers containing sulfonic acid side groups in the membrane matrix to the solvent to form a uniform mixture, and then adds inorganic substances to form a suspension. The suspended solids are broken using nano-crushing technology to obtain a uniformly dispersed slurry, which is then cast into a film. The film structure formed is uniform and quite dense. It not only has good resistance to methanol penetration, but also has good chemical stability and proton conductivity, with a methanol penetration rate of less than 5.