Fluorinated poly(arylene ether sulfide) for polymeric optical waveguide devices

Fluorinated poly(arylene ether sulfide)s containing an ethynyl group (E-FPA ESI) were synthesized by nucleophilic aromatic substitution from 4,4'-(hexa fluoroisopropylidene)diphenol (6FBPA) and an excess of pentafluorophenyl su lfide, followed by reaction with 3-ethynylphenol. The molecular weights (M- n's) and polydispersities (M-w/M-n's) of the E-FPAESI determined by GPC wit h polystyrene standard were in the range 14200-25200 and 2.23-2.47, respect ively. The polymer films were fabricated by spin-coating and cross-linked b y thermal curing. The cured films had good chemical resistance for common s olvents such as acetone, tetrahydrofuran (THF), methylene chloride, chlorof orm, N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO). The glass transition temperature of E-FPAESI was changed from 120 to 160 degreesC aft er curing and showed high thermal stability up to 489 degreesC. At 1.55 mum wavelength, the refractive indices and birefringences of the films were in the range 1.5200-1.5515 and 0.0034-0.0044, respectively, depending on feed ratio of 6FBPA and 4,4'-(trifluoromethylphenylisopropylidene)diphenol (3FB PA). The optical loss for E-FPAESI was measured to be less than 0.40 dB/cm.