Novel fluorinated polymers bearing phosphonated side chains: synthesis, characterization and properties

A new class of aryl trifluorovinyl ether monomers containing phosphonated oligo(ethylene oxide) units were designed and synthesized. Novel fluorinated polymers containing perfluorocyclobutane and phosphonic acid moieties were prepared from these monomers via the thermal cyclopolymerization and hydrolysis reaction. The structures of these monomers and polymers were characterized by nuclear magnetic resonance spectroscopy and fourier transform spectroscopy. The thermal properties of these polymers were evaluated with differential scanning calorimetry and thermo-gravimetric analysis. The 5% weight loss of these polymers was in range of 258–270 °C in nitrogen, but no glass transition temperatures were detected. The polymers showed good solubility in organic solvents such as dimethyl sulfoxide and N,N-dimethylacetamide. In addition, the basic membrane properties of the membranes such as water uptake and proton conductivity were also measured at room temperature. The membranes exhibited high water uptake (up to 44.7%) due to the high level of phosphonation content. The proton conductivities of the membranes under 100% relative humidity were in the range of 0.032–0.068 S/cm, which entitled them as candidates for proton exchange membranes.