Recent advances in polymer synthesis have allowed remarkable control over chain microstructure and conformation. Capitalizing on such developments, here we create well-controlled chain folding in sulfonated polyethylene, leading to highly uniform hydrated acid layers of subnanometre thickness with high proton conductivity. The linear polyethylene contains sulfonic acid groups pendant to precisely every twenty-first carbon atom that induce tight chain folds to form the hydrated layers, while the methylene segments crystallize. The proton conductivity is on par with Nafion 117, the benchmark for fuel cell membranes. We demonstrate that well-controlled hairpin chain folding can be utilized for proton conductivity within a crystalline polymer structure, and we project that this structure could be adapted for ion transport. This layered polyethylene-based structure is an innovative and versatile design paradigm for functional polymer membranes, opening doors to efficient and selective transport of other ions and small molecules on appropriate selection of functional groups.

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E.B.T and K.I.W. acknowledge funding from the National Science Foundation (NSF) DMR 1506726, NSF PIRE 1545884, and the Army Research Office W911NF1310363. T.W.G. and K.B.W. thank the National Science Foundation (DMR1505778) for partial financial support for this project. This material also is based on catalyst work supported by, or in part by, the Army Research Office under the grant W911NF1310362. E.B.T, M.M. and P.R. acknowledge support from the Centre national de la recherche scientifique (CNRS) at the laboratoire des Systèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé in Grenoble, France (UMR5819-SyMMES (CNRS/CEA/Univ. Grenoble Alpes)), and funding from the Agence Nationale de le Recherche (ANR): ANR-15-PIRE-0001-01 and ANR-15-PIRE-0001-07. D.E.M. acknowledges funding from Rachleff Scholars Program of the University of Pennsylvania. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the US Department of Energy (DOE) Office of Science. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the US Department of Energy’s National Nuclear Security Administration under contract DE-NA-0003525. We acknowledge the Laboratory for Research on the Structure of Matter (LRSM), supported by NSF DMR 11-20901. We acknowledge support from the Army Research Office Defense University Research Instrumentation Program (ARO DURIP) grant W911NF-14-1-0466. We acknowledge the Synchrotron SOLEIL for beamtime and financial support, and J.-B. Brubach as a local contact on the AILES beamline for the infrared absorbance data at various humidities. We acknowledge H. Mendil-Jakani for assistance with preliminary X-ray scattering measurements and E. Dubard for experimental support. This research used resources of the Advanced Photon Source, a US DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357. In particular we acknowledge E. Bailey and S. Narayanan of beamline 8-ID-I for the small-angle X-ray scattering data presented in Supplementary Fig. 5. We thank A. Frischknecht (Sandia National Laboratories), A. Patel (University of Pennsylvania) and L. Gonon (UMR5819-SyMMES (CNRS/CEA/Univ. Grenoble Alpes)) for helpful discussions. We thank Materia Inc. for their generous donation of the catalyst used in this project. We thank C. Lee-Georgescu for illustrating Figs. 1b, 2c,d and 4a–c.

Author information


  1. Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, USA

    • Edward B. Trigg
    • , Demi E. Moed
    •  & Karen I. Winey
  2. The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, University of Florida, Gainesville, FL, USA

    • Taylor W. Gaines
    •  & Kenneth B. Wagener
  3. Univ. Grenoble Alpes, CNRS, CEA, INAC-SyMMES, Grenoble, France

    • Manuel Maréchal
    •  & Patrice Rannou
  4. Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, USA

    • Mark J. Stevens


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E.B.T. and K.I.W. generated the main ideas of the project, measured X-ray scattering, conductivity and sorption, performed simulations, analysed all data and wrote most of the text of this paper. T.W.G. and K.B.W. conceived of and carried out the synthesis of the polymer. M.M. and P.R. contributed ideas and interpretation and edited the text. M.M. collected infrared absorbance data and sorption data. D.E.M. collected conductivity data. M.J.S. contributed simulation expertise, ideas and interpretation, and edited the text.

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The authors declare no competing interests.

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Correspondence to Karen I. Winey.

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