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Transferencia de quiralidad de molécula a fase en copolímeros de bloque quiral autoensamblados
Rong-Ming Ho1, Ming-Chia Li, Shih-Chieh Lin
1Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan. rmho@mx.nthu.edu.tw
Journal of the American Chemical Society
|May 25, 2012
Resumen
Los copolímeros de bloque quiral (BCP*) se autoensamblan, transfiriendo la quiralidad molecular a las nanoestructuras helicoidales. Este proceso, impulsado por la separación de microfasas, crea fases homoquirales con una mano predecible.
Área de la Ciencia:
- La ciencia de los polímeros es la ciencia de los polímeros.
- Química supramolecular de las moléculas.
- Estudios de Quiralidad Estudios de Quiralidad
Sus antecedentes:
- Los copolímeros de bloque quiral (BCP*) ofrecen oportunidades únicas para crear nanoestructuras quirales ordenadas.
- La comprensión de los mecanismos de transferencia quiral en el autoensamblaje de BCP es crucial para el diseño de materiales avanzados.
Objetivo del estudio:
- Para dilucidar los mecanismos de transferencia quiral a través de diferentes escalas de longitud durante el autoensamblaje de BCP.
- Demostrar la evolución de la homoquiralidad de la quiralidad molecular a la fase en BCPs enantioméricos*.
- Investigar el papel de la separación de microfasas en la formación de fases helicoidales quirales.
Principales métodos:
- Espectroscopia de dicroísmo circular (CD) y dicroísmo circular vibratorio (VCD) para identificar la quiralidad molecular y la conformación helicoidal.
- Tomografía de microscopía electrónica de transmisión (TEM) para la visualización directa de nanoestructuras helicoidales.
- Espectroscopia de fluorescencia para sondear las interacciones moleculares y los cambios conformacionales.
Principales resultados:
- Se confirmó la quiralidad molecular utilizando CD y VCD, identificando la mano helicoidal.
- Se visualizó la formación de una fase helicoidal (H*) con mano definida a través de la tomografía TEM.
- Se observaron señales de CD inducidas significativas y cambios de fluorescencia en las fracciones de perileno aciral por encima de la concentración crítica de micela.
Conclusiones:
- La transferencia quiral de la quiralidad molecular a la fase se demuestra en el autoensamblaje BCP*.
- La separación de la microfasa en la interfaz inicia un mecanismo de torsión y desplazamiento que conduce a la formación de la fase H*.
- El estudio proporciona información sobre los principios fundamentales que rigen el autoensamblaje quiral en copolímeros de bloque.
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