Solutions + Emulsions
- The most common application for ionomer solutions is in the production of catalyst ink. In order to coat the membrane or gas diffusion layer and make it electrochemically active, solids must be processed in liquids:
- Emulsions/suspensions: Catalyst particles (e.g., platinum on carbon or iridium oxide) are dispersed together with a binding agent (ionomer) in a solvent mixture (usually water and alcohols). This emulsion must be highly stable so that the heavy particles do not settle.
- Application: These inks are applied using processes such as spraying, squeegee coating, or slot die coating. After the solvent has evaporated, the active, porous catalyst layer remains.
