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Cuantificación de los cambios estructurales del ionómero de ácido perfluorosulfonado al reaccionar con radicales
Lida Ghassemzadeh1, Steven Holdcroft
1Department of Chemistry, Simon Fraser University , 8888 University Drive, Burnaby, British Columbia, Canada V5A1S6.
Journal of the American Chemical Society
|May 23, 2013
Resumen
Cuantificamos la degradación química en las membranas del ionómero del ácido perfluorosulfonado (PFSA). La degradación se produce en la cadena lateral, no en la columna vertebral, lo que ofrece un nuevo método para analizar la estabilidad de los ionómeros.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química de Polímeros La química de los polímeros es la química de los polímeros.
- Química Analítica La Química Analítica es la
Sus antecedentes:
- Las membranas de ionómero de ácido perfluorosulfonado (PFSA) son cruciales para las aplicaciones electroquímicas.
- Comprender su degradación química es vital para predecir la vida útil del material.
- Los métodos anteriores carecían de precisión para cuantificar la degradación a nivel molecular.
Objetivo del estudio:
- Para cuantificar la degradación química a nivel molecular de las membranas de ionómero de PFSA.
- Para dilucidar los sitios específicos de degradación dentro de la estructura del ionómero.
- Para establecer un método más preciso para evaluar la estabilidad química del ionómero de PFSA.
Principales métodos:
- Se utilizó la espectroscopia de resonancia magnética nuclear (MAS NMR) calibrada (19) F con ángulo mágico de giro.
- Las membranas de Nafion 211 expuestas a los radicales hidroxilo.
- Seguimiento de segmentos individuales del ionómero para rastrear cambios estructurales.
Principales resultados:
- Se demostró que la columna vertebral del ionomero es resistente al ataque del radical hidroxilo.
- Identificación de degradación que ocurre exclusivamente en la cadena lateral.
- Se observó la degradación más significativa en el extremo de la cadena lateral.
Conclusiones:
- El estudio cuantifica con precisión la degradación del ionómero de PFSA a nivel molecular.
- El ataque del radical hidroxilo ataca la cadena lateral, dejando la columna vertebral intacta.
- Este método basado en RMN aumenta la certeza de la evaluación de los cambios en la estructura química de los iónmeros de PFSA.
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