Aqueous PTFE Dispersion: Tetrafluoroethylene Polymerised in Soapy Water (Berry 1951)

Ordinary soaps stop tetrafluoroethylene from growing into long chains. A fluorine soap does not: with 2 % of ammonium dodecafluoroheptanoate in the water, the gas polymerises into tiny PTFE ribbons that stay suspended. The result is a milky dispersion, a third of it polymer, the raw material for PTFE fine powder. Source: K. L. Berry (du Pont), US 2,559,752 (1951), Example III. Making the ammonium salt from our acid, and the apparatus, are ours. Picture drawn by Youblob.