Abstract
The hydrated morphology of either proton exchange membranes (PEMs) or anion exchange membranes (AEMs) determines many aspects of species transport. The present work seeks to understand the morphology and microstructure of a triblock copolymer, polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS), functionalized with alkyl-substituted quaternary ammonium groups. Mesoscale dissipative particle dynamics (DPD) simulations were utilized and parametrized by reproducing the experimental morphology of the SEBS copolymer. It was found that the AEM (i.e., quaternary ammonium-functionalized SEBS) phase separates into a functionalized polystyrene-rich phase that is hydrophilic and a hydrophobic phase consisting of the SEBS mid-blocks. The morphology was controlled by the water content and was transformed from perforated and interconnected lamellae to perfect lamellae and then to disordered bicontinuous domains by increasing the hydration level (λ = H2O/functional head group) from 4 to 20. The hydrophilic phase swelled upon the hydration of the membrane consistent with AFM phase imaging of a similar SEBS-based ionomer. Domains exclusively consisting of water were formed at high levels of hydration (λ = 16 and 20) within the hydrophilic phase. Changing the anion from OH- to Cl- resulted in larger water domains at the highest hydration levels.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 4397-4405 |
| Number of pages | 9 |
| Journal | Macromolecules |
| Volume | 50 |
| Issue number | 11 |
| DOIs | |
| State | Published - Jun 13 2017 |
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ASJC Scopus subject areas
- Organic Chemistry
- Materials Chemistry
- Polymers and Plastics
- Inorganic Chemistry
Cite this
Mesoscale Simulations of Anion Exchange Membranes Based on Quaternary Ammonium Tethered Triblock Copolymers. / Sepehr, Fatemeh; Liu, Hongjun; Luo, Xubo; Bae, Chulsung; Tuckerman, Mark; Hickner, Michael A.; Paddison, Stephen J.
In: Macromolecules, Vol. 50, No. 11, 13.06.2017, p. 4397-4405.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Mesoscale Simulations of Anion Exchange Membranes Based on Quaternary Ammonium Tethered Triblock Copolymers
AU - Sepehr, Fatemeh
AU - Liu, Hongjun
AU - Luo, Xubo
AU - Bae, Chulsung
AU - Tuckerman, Mark
AU - Hickner, Michael A.
AU - Paddison, Stephen J.
PY - 2017/6/13
Y1 - 2017/6/13
N2 - The hydrated morphology of either proton exchange membranes (PEMs) or anion exchange membranes (AEMs) determines many aspects of species transport. The present work seeks to understand the morphology and microstructure of a triblock copolymer, polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS), functionalized with alkyl-substituted quaternary ammonium groups. Mesoscale dissipative particle dynamics (DPD) simulations were utilized and parametrized by reproducing the experimental morphology of the SEBS copolymer. It was found that the AEM (i.e., quaternary ammonium-functionalized SEBS) phase separates into a functionalized polystyrene-rich phase that is hydrophilic and a hydrophobic phase consisting of the SEBS mid-blocks. The morphology was controlled by the water content and was transformed from perforated and interconnected lamellae to perfect lamellae and then to disordered bicontinuous domains by increasing the hydration level (λ = H2O/functional head group) from 4 to 20. The hydrophilic phase swelled upon the hydration of the membrane consistent with AFM phase imaging of a similar SEBS-based ionomer. Domains exclusively consisting of water were formed at high levels of hydration (λ = 16 and 20) within the hydrophilic phase. Changing the anion from OH- to Cl- resulted in larger water domains at the highest hydration levels.
AB - The hydrated morphology of either proton exchange membranes (PEMs) or anion exchange membranes (AEMs) determines many aspects of species transport. The present work seeks to understand the morphology and microstructure of a triblock copolymer, polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS), functionalized with alkyl-substituted quaternary ammonium groups. Mesoscale dissipative particle dynamics (DPD) simulations were utilized and parametrized by reproducing the experimental morphology of the SEBS copolymer. It was found that the AEM (i.e., quaternary ammonium-functionalized SEBS) phase separates into a functionalized polystyrene-rich phase that is hydrophilic and a hydrophobic phase consisting of the SEBS mid-blocks. The morphology was controlled by the water content and was transformed from perforated and interconnected lamellae to perfect lamellae and then to disordered bicontinuous domains by increasing the hydration level (λ = H2O/functional head group) from 4 to 20. The hydrophilic phase swelled upon the hydration of the membrane consistent with AFM phase imaging of a similar SEBS-based ionomer. Domains exclusively consisting of water were formed at high levels of hydration (λ = 16 and 20) within the hydrophilic phase. Changing the anion from OH- to Cl- resulted in larger water domains at the highest hydration levels.
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U2 - 10.1021/acs.macromol.7b00082
DO - 10.1021/acs.macromol.7b00082
M3 - Article
VL - 50
SP - 4397
EP - 4405
JO - Macromolecules
JF - Macromolecules
SN - 0024-9297
IS - 11
ER -