Revolutionizing the Understanding of Ionomer Morphologies

Revolutionizing the Understanding of Ionomer Morphologies art

Overview: Ionomers have ionic groups covalently bonded to a polymer, and the counter ions are ionically associated with the polymer. The ionic groups and their counter ions associate to form aggregates that provide mechanical reinforcement and were presumed to be spherical. Through more than two decades of effort, the Winey has established that ionomer morphologies encompass a much wider array of aggregate shapes and can even self-assemble into periodic structures. Using a combination of advanced characterization methods and polymers with precise microstructure synthesized by various collaborators, the group identified a host of ionomer morphologies. For example, when the ionic groups are evenly spaced along linear polyethylenes as synthesized by ADMET, the polymer crystallizes with the ionic groups in periodic layers. And when this polymer is melted, the ionic aggregates transform into stringy aggregates. In a precise polymer with neutralized phenyl sulfonate groups on every 5th carbon, the stringy aggregates form percolated networks. When the ionic groups are attached to short blocks in a strictly alternating multiblock copolymer with fixed block lengths, periodic morphologies form including cylinders on a hexagonal lattice, the double-gyroid morphology, and layers. The Winey group was the first report of the double gyroid morphology in a multiblock copolymer.  

  1. J. H. Laurer, K. I. Winey*, Macromolecules, 31, 9106-9108, 1998.“Direct imaging of ionic aggregates in Zn-neutralized poly(ethylene-co-methacrylic acid) copolymers.” https://doi.org/10.1021/ma981503g
  2. N. M. Benetatos, C. D. Chan, K. I. Winey*, Macromolecules, 40, 1081-1088, 2007. “Quantitative morphology study of Cu-neutralized poly(styrene-ran-methacrylic acid) ionomers:  STEM imaging, X-ray scattering, and real space structural modeling.” https://doi.org/10.1021/ma0621371  
  3. T. W. Baughman, C. D. Chan, K. I. Winey*, K. B. Wagener*, Macromolecules, 40, 6564-6571, 2007. “Synthesis and morphology of well-defined poly(ethylene-co-acrylic acid) copolymers.” https://doi.org/10.1021/ma070841r
  4. JACS cover
    M. E. Seitz, C. D. Chan, K. L. Opper, T. W. Baughman, K. B. Wagener, K. I. Winey*, Journal of the American Chemical Society, 132, 8165-8174, 2010.  “Nanoscale morphology in precisely-sequenced poly(ethylene-co-acrylic acid) zinc ionomers.” https://doi.org/10.1021/ja101991d
  5. C. F. Buitrago, K. L. Opper, K. B. Wagener, K. I. Winey*, ACS Macro Letters, 1, 71-74, 2012. “A precise acid copolymer exhibits a face-centered cubic structure.” https://doi.org/10.1021/mz2000237
  6. E. B. Trigg, M. J. Stevens, K. I. Winey*, Journal of the American Chemical Society, 139, 3747-3755, 2017. “Chain folding produces a multilayered morphology in a precise polymer: Simulations and experiments.” https://doi.org/10.1021/jacs.6b12817
  7. Yan JACS cover 2020
    Lu Yan, C. Rank, S. Mecking, K. I. Winey*, Journal of the American Chemical Society, 142, 857-866, 2020. “Gyroid and other ordered morphologies in single-ion conducting polymers and their impact on ion conductivity.” https://pubs.acs.org/doi/full/10.1021/jacs.9b09701; 6 citations
  8. Jinseok Park, A. Staiger, S. Mecking, K. I. Winey*, ACS Nano, 15, 16738–16747, 2021. “Sub-3-nanometer domain spacings of ultrahigh-c multiblock copolymers with pendant ionic groups.” https://doi.org/10.1021/acsnano.1c06734
  9. Jinseok Park, A. Staiger, S. Mecking, K. I. Winey*, ACS Central Science, 8, 388–393, 2022. “Ordered nanostructures in thin films of precise ion-containing multiblock copolymers.” https://doi.org/10.1021/acscentsci.1c01594