High Proton-Conductivity in Covalently Linked Polyoxometalate- Organoboronic Acid-Polymers

Abstract

The controlled bottom-up design of polymers with metal oxide backbones is a grand challenge in materials design, as it could give unique control over the resulting chemical properties. Herein, we report a 1D-organo-functionalized polyoxometalate polymer featuring a purely inorganic backbone. The polymer is self-assembled from two types of monomers, inorganic Wells–Dawson-type polyoxometalates, and aromatic organo-boronates. Their covalent linkage results in 1D polymer strands, which combine an inorganic oxide backbone (based on B−O and Nb−O linkages) with functional organic side-chains. The polymer shows high bulk proton conductivity of up to 1.59×10−1 S cm−1 at 90 °C and 98 % relative humidity. This synthetic approach could lead to a new class of organic–inorganic polymers where function can be designed by controlled tuning of the monomer units.