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Title: Self-Assembly of a Midblock-Sulfonated Pentablock Copolymer in Mixed Organic Solvents: A Combined SAXS and SANS Analysis

Abstract

Ionic, and specifically sulfonated, block copolymers are continually gaining interest in the soft materials community due to their unique suitability in various ion exchange applications such as fuel cells, organic photovoltaics, and desalination membranes. One unresolved challenge inherent to these materials is solvent templating, that is, the translation of self-assembled solution structures into non equilibrium solid film morphologies. Recently, the use of mixed polar/nonpolar organic solvents has been examined in an effort to elucidate and control the solution self-assembly of sulfonated block copolymers. The current study sheds new light on micellar assemblies (i.e., those with the sulfonated blocks comprising the micellar core) of a midblock-sulfonated pentablock copolymer in polar/nonpolar solvent mixtures by combining small-angle X-ray and small-angle neutron scattering. Our scattering data reveal that micelle size depends strongly on overall solvent composition: micelle cores and coronae grow as the fraction of nonpolar solvent is increased. Universal model fits further indicate that an unexpectedly high fraction of the micelle cores is occupied by polar solvent (60-80 vol %) and that partitioning of the polar solvent into micelle cores becomes more pronounced as its overall quantity decreases. This solvent presence in the micelle cores explains the simultaneous core/corona growth, which is otherwisemore » counterintuitive. Furthermore our findings provide a potential pathway for the formation of solvent-templated films with more interconnected morphologies due to the greatly solvated micellar cores in solution, thereby enhancing the molecular, ion, and electron-transport properties of the resultant films.« less

Authors:
ORCiD logo [1];  [2];  [3]; ORCiD logo [4]; ORCiD logo [5]; ORCiD logo [2]
  1. Bucknell Univ., Lewisburg, PA (United States)
  2. North Carolina State Univ., Raleigh, NC (United States)
  3. Forschungszentrum Julich, Garching (Germany)
  4. Argonne National Lab. (ANL), Argonne, IL (United States)
  5. Technische Univ. Berlin, Berlin (Germany)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
North Carolina State University; National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division
OSTI Identifier:
1504271
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Accepted Manuscript
Journal Name:
Langmuir
Additional Journal Information:
Journal Volume: 35; Journal Issue: 4; Journal ID: ISSN 0743-7463
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Mineart, Kenneth P., Ryan, Justin J., Appavou, Marie -Sousai, Lee, Byeongdu, Gradzielski, Michael, and Spontak, Richard J. Self-Assembly of a Midblock-Sulfonated Pentablock Copolymer in Mixed Organic Solvents: A Combined SAXS and SANS Analysis. United States: N. p., 2019. Web. doi:10.1021/acs.langmuir.8b03825.
Mineart, Kenneth P., Ryan, Justin J., Appavou, Marie -Sousai, Lee, Byeongdu, Gradzielski, Michael, & Spontak, Richard J. Self-Assembly of a Midblock-Sulfonated Pentablock Copolymer in Mixed Organic Solvents: A Combined SAXS and SANS Analysis. United States. https://doi.org/10.1021/acs.langmuir.8b03825
Mineart, Kenneth P., Ryan, Justin J., Appavou, Marie -Sousai, Lee, Byeongdu, Gradzielski, Michael, and Spontak, Richard J. Fri . "Self-Assembly of a Midblock-Sulfonated Pentablock Copolymer in Mixed Organic Solvents: A Combined SAXS and SANS Analysis". United States. https://doi.org/10.1021/acs.langmuir.8b03825. https://www.osti.gov/servlets/purl/1504271.
@article{osti_1504271,
title = {Self-Assembly of a Midblock-Sulfonated Pentablock Copolymer in Mixed Organic Solvents: A Combined SAXS and SANS Analysis},
author = {Mineart, Kenneth P. and Ryan, Justin J. and Appavou, Marie -Sousai and Lee, Byeongdu and Gradzielski, Michael and Spontak, Richard J.},
abstractNote = {Ionic, and specifically sulfonated, block copolymers are continually gaining interest in the soft materials community due to their unique suitability in various ion exchange applications such as fuel cells, organic photovoltaics, and desalination membranes. One unresolved challenge inherent to these materials is solvent templating, that is, the translation of self-assembled solution structures into non equilibrium solid film morphologies. Recently, the use of mixed polar/nonpolar organic solvents has been examined in an effort to elucidate and control the solution self-assembly of sulfonated block copolymers. The current study sheds new light on micellar assemblies (i.e., those with the sulfonated blocks comprising the micellar core) of a midblock-sulfonated pentablock copolymer in polar/nonpolar solvent mixtures by combining small-angle X-ray and small-angle neutron scattering. Our scattering data reveal that micelle size depends strongly on overall solvent composition: micelle cores and coronae grow as the fraction of nonpolar solvent is increased. Universal model fits further indicate that an unexpectedly high fraction of the micelle cores is occupied by polar solvent (60-80 vol %) and that partitioning of the polar solvent into micelle cores becomes more pronounced as its overall quantity decreases. This solvent presence in the micelle cores explains the simultaneous core/corona growth, which is otherwise counterintuitive. Furthermore our findings provide a potential pathway for the formation of solvent-templated films with more interconnected morphologies due to the greatly solvated micellar cores in solution, thereby enhancing the molecular, ion, and electron-transport properties of the resultant films.},
doi = {10.1021/acs.langmuir.8b03825},
journal = {Langmuir},
number = 4,
volume = 35,
place = {United States},
year = {Fri Jan 04 00:00:00 EST 2019},
month = {Fri Jan 04 00:00:00 EST 2019}
}

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