One F‑Octyl versus Two F‑Butyl Chains in Surfactant Aggregation Behavior

An easy synthetic procedure in two or three steps from perfluoroalkylethyl iodide derivatives led to six novel fluorinated carboxylates monomeric and gemini surfactants with one or two hydrophobic tails, respectively: R_F(C₂H₄)­CH­(CO₂^–)₂,2Na⁺ and [R_F(C₂H₄)]₂C­(CO₂^–),Na⁺, where R_F = C₄F₉, C₆F₁₃, and C₈F₁₇. These anionic surfactants exhibited very low surface tension from 15 to 33 mN/m as well as low critical micelle concentration until 1.3 × 10^–4 mol/L. Furthermore, the surface properties of the gemini compound with two short fluoroalkyl chains (R_F = C₄F₉) were found to be almost equal to those of the monomeric surfactant with one long fluoroalkyl chain (R_F = C₈F₁₇), which could provide an interesting alternative to the bioaccumulative long-chain perfluorinated surfactant.