Enhancement of anhydrous proton transport by supramolecular nanochannels in comb polymers

Abstract

Transporting protons is essential in several biological processes as well as in renewable energy devices, such as fuel cells. Although biological systems exhibit precise supramolecular organization of chemical functionalities on the nanoscale to effect highly efficient proton conduction, to achieve similar organization in artificial systems remains a daunting challenge. Here, we are concerned with transporting protons on a micron scale under anhydrous conditions, that is proton transfer unassisted by any solvent, especially water. We report that proton-conducting systems derived from facially amphiphilic polymers that exhibit organized supramolecular assemblies show a dramatic enhancement in anhydrous conductivity relative to analogous materials that lack the capacity for self-organization. We describe the design, synthesis and characterization of these macromolecules, and suggest that nanoscale organization of proton-conducting functionalities is a key consideration in obtaining efficient anhydrous proton transport.

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Figure 1: Structures and synthesis of benzotriazole-based polymers.
Figure 2: Conductivity and SAXS results for benzotriazole polymers.
Figure 3: Results for imidazole-based polymers

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Acknowledgements

This work was supported by the National Science Foundation through the Fueling the Future Center for Chemical Innovation at the University of Massachusetts Amherst (CHE-0739227). We thank W. de Jeu for discussions on the X-ray scattering results.

Author information

S.T. and Y.C. conceived the molecular design. S.T., R.H. and Mark T. planned the project. Y.C, Michael T., S.C. and C.V. carried out the experiments and analysed the data. Y.C. and A.P. synthesized the discussed compounds, Michael T. and C.V. measured ionic conductivities, and S.C. performed SAXS. Results were discussed by R.H., Mark T. and S.T. All authors contributed to writing the manuscript.

Correspondence to Ryan C. Hayward or Mark T. Tuominen or S. Thayumanavan.

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The authors declare no competing financial interests.

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