Gemini cationic surfactants with flexible perfluorinated-ether chains

This research aims at providing alternatives for long-chain fluorosurfactants, such as perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS) and their derivatives. Gemini quaternary ammonium fluorosurfactants with perfluorinated-ether chains were synthesized and their surface tensions were measured. The surface tensions at critical micelle concentration (gamma(cmc)) are at the range of 14.7-23.3 mN/m and among them gamma(cmc) of four perfluorinated-chain surfactants are below 16 mN/m.We found that the flexibility of perfluorinated-ether chains, such as CF3(OCF2)(n)-, contributed significantly to enhance the surface activities. We also synthesized gemini cationic surfactants with C6F13CH2CH2- groups and their gamma(cmc) are between 15.5 to 20.1 mN/m. Good linkage design, such as -(CH2)n- (where n is odd), -CH2CH2OCH2CH2- and 1,2-phenylenebis(methylene), helps for lowering surface energy. The current research provides an approach for discovering non-bioaccumulative surfactants.