Novel synthesis of linear perfluorinated poly(phenylene sulfide) from aryl sulfoxide

The linear perfluorinated poly(phenylene sulfide) [poly(thio-2,3,5,6-tetrafluoro-1,4-phenylene)] has been successfully prepared by polycondensation of 4-(methylsulfinyl)-2,3,5,6-tetrafluorophenyl 2,3,5,6-tetrafluorophenyl sulfide in an electrophilic reaction via the polysulfonium salt as a precursor. The polymerization proceeds efficiently in trifluoromethanesulfonic acid with the addition of phosphorus pentoxide as a dehydrating agent to produce the polymer in 100% yield. The polymer obtained is only partly soluble in 1-chloronaphthalene at 210 °C. The molecular weight (M_w) of the soluble part of the polymer is ∼4000 as determined by high-temperature gel permeation chromatography. The polymer has a melting temperature of 373 °C, which is 88 °C higher than that of the unfluorinated analog (285 °C). The contact angle measurements show that the surface energy of the polymer (σ_s = 41 mN/m) is comparable to those of poly(ethylene terephthalate) and polystyrene.