Abstract
Fluorinated surfactants with the general formula of CF3CF2CF2-O-[CF(CF3)CF2-O-]n-2-CF(CF3)-COONa [Rf-n, Rf: hydrophobic group, n: oligomerization degree, n=26] were synthesized from the corresponding hexafluoropropene oxide oligomer.
The properties of these surfactant solutions such as surface tensions, Krafft points, foam capacities, and chemical stabilities were measured. With an increase of oligomerization degree cmc decreased and the minimum cmc was obtained for surfactant Rf-5. The secondary cmc was observed for surfactant Rf-4, 5, and 6.
Unlike the conventional fluorinated surfactants, the Krafft points of all the present surfactants showed below 0°C. It may be attributed to flexibility of hydrophobic groups containing ether type oxygen and chain branching.
The foam capacities of these surfactants were not excellent, but foam stability of surfactant Rf-4 was relatively high.
The present surfactants were also stable against acidic and alkaline solutions as well as many other fluorinated surfactants. This investigation indicates that these materials are noted as an excellent surfactants.
