Fluoropolymer Nanoparticles Prepared Using Trifluoropropene Telomer Based Fluorosurfactants
By Ma W, Lopez G, Ameduri B, and Takahara A.
February 11, 2020
A fluorosurfactant based on 3,3,3-trifluoropropene (TFP) telomer was synthesized as an environmentally friendly alternative to perfluorooctanoic acid (PFOA) using TFP and 2-iodoperfluoropropane ((CF3)2CF-I) as starting materials. TFP telomerization was initiated by addition of di-tert-butylperoxide in the presence of (CF3)2CF-I as a chain transfer agent. The surfactant was obtained by modification of the iodine end-group on the TFP telomer to form an allylic functionality followed by the addition of thioglycolic acid via a thiol-ene reaction. The resulting fluorosurfactant exhibited a lower critical micellar concentration (CMC= 0.87 g.L-1) than PFOA (CMC= 3.0 g.L-1). This surfactant was used to prepare fluoropolymer nanoparticles by solvent evaporation from a solution composed of the surfacant and poly[2-(perfluorobutyl)ethyl methacrylate]. The oil-in-water emulsion was initially formed due to the adsorption of the surfactant molecules at the oil/water interface and subsequently converted into a nanoparticle suspension after solvent evaporation. Because of the strong hydrophobic interactions between the fluorinated surfactant tail and fluoropolymer, the obtained nanoparticle suspension was quite stable against water dialysis.
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