Molecular dynamics study on water and hydroxide transfer mechanisms in PSU-g-alkyl-TMA membranes at low hydration: Effect of side chain length

Magnico, Pierre

doi:10.1016/j.ijhydene.2021.07.081

Cited by 5 publications

(2 citation statements)

References 76 publications

(64 reference statements)

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“…PET-Bm (OH – )-15D shows the highest alkaline stability of 432 h respected to other membranes (7D and 11D) due to the higher number of cationic groups in the modified PET structure. The amine functional groups present in PET-Bm(OH – )- are susceptible to nucleophilic substitution reactions in alkaline environments, forming new compounds and losing the original structure. This process results in a reduction of the cation head groups and subsequently affects the OH – conductivity …”

Section: Resultsmentioning

confidence: 99%

Anion Exchange Membranes Based on Chemical Modification of Recycled PET Bottles

Donnakatte Neelalochana,

Tomasino,

Di Maggio

et al. 2023

ACS Appl. Polym. Mater.

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This study presents an innovative and effective solution for recycling PET bottles as raw for producing anion exchange membranes (AEMs) for electrochemical applications. This approach reduces the demand for pristine materials, a key principle of the circular economy and sustainability. PET was subjected to chemical modification by introducing cationic functional groups followed by methylation and OH– exchange process. The amination synthesis was optimized based on reaction time. The results indicate that ion exchange capacity, water uptake, and swelling ratio properties mainly depend on the degree of cationic functionalization. The optimized AEM exhibits ionic conductivity of 5.3 × 10–2 S·cm–1 and alkaline stability of 432 h in 1 M KOH at 80 °C. The membrane properties before and after the alkaline treatment were investigated using Fourier-transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy analysis. Computational chemistry analysis was employed to gain further insights into the membrane degradation mechanisms and pathways under alkaline conditions. This research and its findings are a step toward using recycled materials in the field of AEM technology.

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Section: Resultsmentioning

confidence: 99%

Anion Exchange Membranes Based on Chemical Modification of Recycled PET Bottles

Donnakatte Neelalochana,

Tomasino,

Di Maggio

et al. 2023

ACS Appl. Polym. Mater.

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“…It is highly desirable to fundamentally understand the correlation between mechanical deformation and the morphology and ion conductivity of AEMs, to allow morphology-conductivity relationships to be possibly quantified. Molecular dynamics (MD) simulation is a powerful tool to investigate the influence of mechanical stretching on macromolecular orientation at the atomic level (Ouma et al, 2022) especially to give insights into changes in structure and ion transport properties (Wei et al, 2015;Hofmann et al, 2010;Sengupta et al, 2017;Feng and Voth, 2019;Kurihara et al, 2019;Mabuchi and Tokumasu, 2014;Savage, 2021;Savage and Voth, 2014;Savage and Voth, 2016), membrane morphology (Petersen and Voth, 2006;Komarov et al, 2013;Kuo et al, 2016), water sorption and permeation (Daly et al, 2013;Daly et al, 2014), and mechanical properties (Sun et al, 2013;Ozmaian andNaghdabadi, 2015 Xie et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Microstructural orientation of anion exchange membrane through mechanical stretching for improved ion transport

Zheng

Wang

Zhang

et al. 2023

Front. Membr. Sci. Technol.

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Synthesis of anion exchange membranes (AEMs) with orientated nano/micro-structure and with tunable ion-channels is of great interest for applications in fuel cells, water electrolyzers, and redox flow batteries. However, there is still a dearth of work in the detailed understanding of anion conductivity from a polymer structure‒property perspective. Herein, we demonstrate an easy and versatile strategy to fabricate highly conductive AEMs. By stretching the AEMs, an improvement in OH− conductivities of AEMs is achieved. The effect of elongation at different water contents on polymer structures and OH− conductivities was investigated by a combination of molecular dynamics (MD) simulation and experimental study, giving insights into macromolecular orientation at the atomic level. The morphological changes, which consist of oriented polymer chains and elongated water clusters, are quantified by a combination of two dimensional small angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and radial distribution functions. Detailed analyses of interatomic distances reveal morphological variations of hydrophilic domains and their interactions with water and OH− under elongation at different hydration levels. Furthermore, the OH− conductivities of our synthesized quaternized poly(2,6-dimethyl-1,4-phenylene oxide) (QPPO) AEMs increased significantly after stretching to 20% elongation at all water contents. Specifically, OH− conductivity of stretched QPPO was 2.24 times more than the original AEM at 60% RH. The higher relative increase in OH− conductivity at lower water content may be caused by the lower flexibility of side chains at lower hydrated level. This work verifies the significance of porous and/or oriented AEM structure in the improvement on anion conductivity and water transport efficiency.

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