Perforated nickel sheets can be covered with polytetrafluoroethylene (PTFE Teflon) and used as diaphragms in water electrolyzers. The technique used consists of filling the sheet holes with camphor, spraying PTFE latex on them, and allowing the solid camphor to evaporate. Since the holes are left unclogged, the membrane has good ionic conductivity. However, electronic transport, because the nickel surface is covered by Teflon, is negligible. The hydrophobicity imparted by PTFE to the metal surface has a beneficial effect on gas bubble release during electrolysis. Insulating characteristics of the PTFE coating make this diaphragm adequate for use in sandwich arrangements for bipolar cells.
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Teschke et al. (1983) studied this question.