Fluorinated poly(arylene ether sulfone)s for polymeric optical waveguide devices

Pentafluorophenyl sulfone was prepared by oxidation of pentafluorophenyl sulfide. Ethynyl terminated fluorinated poly(arylene ether sulfone) (EFPAESO) was synthesized via nucleophilic aromatic substitution from 4,4′-(hexafluoroisopropylidene) diphenol or 4,4′-(trifluoromethylphenylisopropylidene) diphenol with an excess of pentafluorophenyl sulfone, followed by reaction with 3-ethylnylphenol. The molecular weights (Mns) of the polymers determined by GPC with polystyrene standard were in the range of 6,400–17,200 and polydispersities (Mw/Mns) were in the range of 2.25–3.19. This EFPAESO showed very high thermal stability up to 479 °C for 5% weight loss in TGA in air. Tg of the polymer was changed from 148 to 196 °C after curing. The cured films showed good chemical resistance and high thermal-stability. At 1550 nm wavelength, the refractive indices of the copolymer films were in the range of 1.5037–1.5504 and birefringences were in the range of 0.0021–0.0025. The optical loss for EFPAESO was less than 0.37 dB/cm at 1550 nm wavelength.