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Creación de superficies sensibles con cinética de conmutación de humedabilidad a medida y reversibilidad de
1Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, USA.
Journal of the American Chemical Society
|December 15, 2005
Resumen
Las superficies de elastómeros sensibles se crearon mediante la modificación de las redes de poli (vinilmetilsiloxano). Estas superficies exhiben una reestructuración inducida por el agua ajustable, con cinética más rápida para espaciadores de metileno más cortos, lo que permite una conmutación de humedabilidad duradera y de baja histeresis.
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 ofrecen un control dinámico sobre las propiedades de la superficie.
- Los elastómeros con reconstrucción de superficie sintonizable son valiosos para aplicaciones avanzadas.
- El control de la cinética de reorganización superficial e histeresis es crucial para el rendimiento del material.
Objetivo del estudio:
- Desarrollar superficies sensibles con una cinética de reconstrucción de superficie adaptable y una histeresis de conmutación.
- Para investigar el efecto de la longitud de la cadena de mercaptoalkanol en el comportamiento de la superficie.
- Comprender los mecanismos que rigen la reorganización de la superficie y el cambio de humedabilidad.
Principales métodos:
- Adición del radical tioleno de los mercaptoalcanolos a las redes de poli (vinilmetilsiloxano).
- Fabricación de superficies de elastómero con diferentes longitudes de espaciador de metileno (n).
- Mediciones del ángulo de contacto con el agua para cuantificar los cambios en la wettability y la cinética.
- Espectroscopia infrarroja (IR) para detectar cambios estructurales como la formación de regiones semicristalinas.
Principales resultados:
- La cinética de la reconstrucción de la superficie disminuyó con el aumento de los espaciadores de metileno (n).
- La cinética de respuesta rápida (por ejemplo, ~2 grados/s para n=3) se observa para n=2 y n=6.
- Los materiales demostraron una longevidad de conmutación de más de 10 ciclos con una histeresis mínima.
- El aumento de n (n = 11) condujo a una disminución drástica de la reorganización de la superficie y eventual congelación de la superficie.
- Formación de regiones semicristalinas correlacionadas con cinética lenta y congelación de la superficie.
Conclusiones:
- La cinética de reconstrucción de la superficie adaptable y la histeresis se logran a través de la longitud controlada de la cadena de mercaptoalkanol.
- La flexibilidad de la columna vertebral del siloxano garantiza la longevidad de la conmutación y una baja histeresis.
- La congelación de la superficie debido a regiones semicristalinas limita la capacidad de respuesta para cadenas más largas.
- Estos hallazgos permiten el diseño de materiales sensibles avanzados con un comportamiento de superficie predecible.
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