Synthesis and properties of gemini-type hydrocarbon–fluorocarbon hybrid surfactants

Gemini-type hybrid surfactants with two fluorocarbon chains connected through a hydrocarbon spacer, F(CF2)m(CH2)2CH(OSO3Na)(CH2)nCH(OSO3Na)(CH2)2(CF2)mF [Fm(Hn)FmOS, m = 4, 6; n = 5, 6, 7, 8)], were synthesized and their surface chemical properties were examined with the aim to have highly functional and highly water-soluble fluorinated surfactants when compared with the conventional fluorinated surfactants. Comparisons of the surface chemical properties of the synthesized gemini-type hybrid surfactants with those of monounit-type hybrid surfactants, F(CF2)m(CH2)2CH(OSO3Na)(CH2)nH [FmEHnOS, m = 4, 6; n = 3, 5)], revealed that gemination causes a remarkable lowering (about 1/100) in cmc value while it produces little changes in Krafft point (below 0 °C) and surface tension at cmc (γcmc).