Anhydrous Proton Transport within Phosphonic Acid Layers in Monodisperse Telechelic Polyethylenes

Polymers bearing phosphonic acid groups have been proposed as anhydrous proton-conducting membranes at elevated operating temperatures for applications in fuel cells. However, the synthesis of phosphonated polymers and control over nanostructure such is challenging. Here, we report straightforward acid-terminated, long-chain aliphatic materials with precisely 26 48 carbon atoms (C26PA2 C48PA2). These combine structuring ability monodisperse polyethylenes to form strong hydrogen-bonding networks. Anhydride formation absent so that charge carrier loss by a condensation reaction avoided even temperatures. Below melting temperature (Tm), both exhibit crystalline polyethylene backbone layered morphology planar aggregates separated 29 55 A C26PA2 C48PA2, respectively. Above Tm, amorphous (PE) segments coexist aggregates. This phenomenon especially pronounced identified thermotropic smectic liquid phase. Under these conditions, an extraordinarily high correlation length (940 A) along layer normal observed, demonstrating strength hydrogen bond network formed groups. The proton conductivity absence water reaches 10-4 S/cm 150 °C. new precise acid-based illustrate importance controlling chemistry self-assembled nanoscale facilitate rapid conductivity.