Swelling of individual nanodomains in hydrated block copolymer electrolyte membranes
[1];
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
- 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
In this work, 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 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 Φ v.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; National Institutes of Health (NIH); USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Contributing Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
- Grant/Contract Number:
- AC05-00OR22725; AC02-05-CH11231; GM051487; AC02-05CH11231
- OSTI ID:
- 1471824
- Alternate ID(s):
- OSTI ID: 1461038; OSTI ID: 1580332
- Journal Information:
- Journal of Chemical Physics, Vol. 149, Issue 16; ISSN 0021-9606
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Phase Behavior of Salt-Doped A/B/AB Ternary Polymer Blends: The Role of Homopolymer Distribution
Block Copolymer Membranes for Efficient Capture of a Chemotherapy Drug