AbstractThe use of the Williamson reaction to prepare polyfluoroethers, [OArOCH2(CF2)3CH2]nfrom 1,1,5,5‐tetrahydryl‐F‐1,5‐pentanediol and polyfluoroaromatic and polyfluoroheteroaromatic compounds was investigated. Fluorine NMR spectroscopy was used to determine the structures of the resultant polymers.F‐Biphenyl and 1,5‐bis(F‐2‐pyridyloxy)‐1,1,5,5‐tetrahydryl‐F‐pentane (BPFP) afforded the polymers where Ar is 4,4′‐C6F4C6F4andrespectively. The polymer prepared fromF‐pyridine differed from that obtained from BPFP in that it had an irregular structure and contained 2,4′‐ as well as 2,2′ ‐ and 4,4′‐linked rings.F‐Benzene, 4‐(1,1‐dihydryl‐F‐butoxy)‐F‐pyridine, andF‐pyrimidine each gave materials having copolymer structures. The inherent viscosities of the polymers depended on the polyfluorocyclic compound used and ranged from 0.05 to 0.2 dl/g. The heterocyclic polymers were elastomeric. The polymers fromF‐pyridine and BPFP had the lowest glass transition temperatures (∼−10°C), and started to lose weight (by