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Title: Swelling of individual nanodomains in hydrated block copolymer electrolyte membranes

Here, we examine the swelling of nanostructured block copolymer electrolytes immersed in liquid water. A series of sulfonated polystyrene-b-polyethylene-b-polystyrene (S-SES) membranes having the same nominal chemical composition but two different morphologies are prepared by systematic changes in processing. We start with a membrane comprising a mixture of homopolymer polystyrene (hPS) and a polystyrene-b-polyethylene-b-polystyrene (SES) copolymer. hPS is subsequently selectively removed from the membrane and the polystyrene domains are sulfonated to give S-SES membranes. The morphology of the membranes is controlled by controlling Φ v, the volume fraction of hPS in the blended membrane. The morphology of the membranes was studied by small angle X-ray scattering (SAXS), cryogenic scanning transmission electron microscopy (cryo-STEM), and cryogenic electron tomography. The overall domain swelling measured by SAXS decreases slightly at Φ v = 0.29; a crossover from lamellar to bicontinuous morphology is obtained at the same value of Φ v. The bicontinuous morphologies absorb more water than the lamellar morphologies. By contrast, the nanodomain swelling of the bicontinuous membrane (120%) is slightly less than that of the lamellar membrane (150%). Quantitative analysis of the STEM images and electron tomography was used to determine the swelling on the hydrophilic and hydrophobic domains due to exposuremore » to water. The hydrophilic sulfonated polystyrene-rich domain spacing increases while the hydrophobic polyethylene domain spacing decreases when the membranes are hydrated. The extent of increase and decrease is not a strong function of Φ v.« less
Authors:
ORCiD logo [1] ;  [1] ;  [2]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division and Energy Technologies Area; Univ. of California, Berkeley, CA (United States). Dept. of Chemical and Biomolecular Engineering
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-05-CH11231; GM051487
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 149; Journal Issue: 16; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; National Institutes of Health (NIH)
Contributing Orgs:
SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; electrolytes; polymers; nanodomains; scanning electron microscopy; x-ray scattering; fuel cells; tomography
OSTI Identifier:
1471824
Alternate Identifier(s):
OSTI ID: 1461038

Chen, X. Chelsea, Jiang, Xi, and Balsara, Nitash P.. Swelling of individual nanodomains in hydrated block copolymer electrolyte membranes. United States: N. p., Web. doi:10.1063/1.5029452.
Chen, X. Chelsea, Jiang, Xi, & Balsara, Nitash P.. Swelling of individual nanodomains in hydrated block copolymer electrolyte membranes. United States. doi:10.1063/1.5029452.
Chen, X. Chelsea, Jiang, Xi, and Balsara, Nitash P.. 2018. "Swelling of individual nanodomains in hydrated block copolymer electrolyte membranes". United States. doi:10.1063/1.5029452.
@article{osti_1471824,
title = {Swelling of individual nanodomains in hydrated block copolymer electrolyte membranes},
author = {Chen, X. Chelsea and Jiang, Xi and Balsara, Nitash P.},
abstractNote = {Here, we examine the swelling of nanostructured block copolymer electrolytes immersed in liquid water. A series of sulfonated polystyrene-b-polyethylene-b-polystyrene (S-SES) membranes having the same nominal chemical composition but two different morphologies are prepared by systematic changes in processing. We start with a membrane comprising a mixture of homopolymer polystyrene (hPS) and a polystyrene-b-polyethylene-b-polystyrene (SES) copolymer. hPS is subsequently selectively removed from the membrane and the polystyrene domains are sulfonated to give S-SES membranes. The morphology of the membranes is controlled by controlling Φv, the volume fraction of hPS in the blended membrane. The morphology of the membranes was studied by small angle X-ray scattering (SAXS), cryogenic scanning transmission electron microscopy (cryo-STEM), and cryogenic electron tomography. The overall domain swelling measured by SAXS decreases slightly at Φv = 0.29; a crossover from lamellar to bicontinuous morphology is obtained at the same value of Φv. The bicontinuous morphologies absorb more water than the lamellar morphologies. By contrast, the nanodomain swelling of the bicontinuous membrane (120%) is slightly less than that of the lamellar membrane (150%). Quantitative analysis of the STEM images and electron tomography was used to determine the swelling on the hydrophilic and hydrophobic domains due to exposure to water. The hydrophilic sulfonated polystyrene-rich domain spacing increases while the hydrophobic polyethylene domain spacing decreases when the membranes are hydrated. The extent of increase and decrease is not a strong function of Φv.},
doi = {10.1063/1.5029452},
journal = {Journal of Chemical Physics},
number = 16,
volume = 149,
place = {United States},
year = {2018},
month = {7}
}

Works referenced in this record:

Self-Assembly and Transport Limitations in Confined Nafion Films
journal, January 2013
  • Modestino, Miguel A.; Paul, Devproshad K.; Dishari, Shudipto
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  • DOI: 10.1021/ma301999a