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Películas de copolímero sensibles al pH por el crecimiento catalizado superficialmente.
Dongshun Bai1, Brian M Habersberger, G Kane Jennings
1Department of Chemical Engineering, Vanderbilt University, Nashville, Tennessee 37235, USA.
Journal of the American Chemical Society
|November 25, 2005
Resumen
Desarrollamos nuevas películas poliméricas sensibles al pH (PM-CO2H) que cambian las propiedades de barrera con el pH. Estas películas muestran un cambio de magnitud de 5 órdenes en la resistencia al transporte iónico, ajustable de pH 5 a 10.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química de Polímeros La Química de Polímeros es la química de los polímeros.
- Ciencias de la superficie Ciencias de la superficie.
Sus antecedentes:
- Los materiales sensibles al pH son cruciales para las propiedades de las superficies sintonizables.
- Los materiales existentes a menudo carecen de respuestas significativas y sintonizables en un amplio rango de pH.
- La polimerización controlada y la modificación de la superficie son claves para la ingeniería de películas funcionales avanzadas.
Objetivo del estudio:
- Para diseñar una nueva clase de películas poliméricas sensibles al pH en superficies de oro.
- Investigar la relación entre la composición del polímero y los cambios de propiedades inducidos por el pH.
- Para demostrar las propiedades de barrera de transporte de iones sintonizables basadas en el pH.
Principales métodos:
- La polimerización catalizada por la superficie para crear películas de copolímero de poli (metileno-coetil acetato).
- Hidrólisis controlada de las cadenas laterales de éster para introducir grupos ácidos carboxílicos (PM-CO2H).
- Espectroscopia de impedancia electroquímica (EIS), espectroscopia infrarroja de reflexión y absorción (RAIRS) y mediciones de ángulo de contacto para caracterizar las propiedades de la película.
Principales resultados:
- Las películas PM-CO2H exhiben un cambio de magnitud de 5 órdenes en la resistencia al transporte iónico sobre 2-3 unidades de pH a un contenido de ácido molar del 1% al 4%.
- El rango de respuesta del pH se puede adaptar de pH 5 a 10 ajustando el contenido de ácido carboxílico.
- La naturaleza hidrofóbica de la columna vertebral del polimetileno mejora la respuesta inducida por el pH a la ionización.
Conclusiones:
- Las películas de ingeniería PM-CO2H muestran propiedades de barrera sensibles al pH significativas y ajustables.
- La polimerización y la hidrólisis controladas ofrecen un control preciso sobre la composición y la funcionalidad de la película.
- Estos materiales son prometedores para aplicaciones que requieren un control dinámico de las propiedades de la superficie en respuesta a los cambios de pH.
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