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Los conjuntos cúbicos hexagonales y bicontinuos normales entrelazados a través de gemini amphiphiles polimerizables
Brad A Pindzola1, Jizhu Jin, Douglas L Gin
1Department of Chemistry, University of California, Berkeley, California 94720, USA.
Journal of the American Chemical Society
|March 6, 2003
Resumen
Los investigadores desarrollaron nuevos surfactantes gemini polimerizables que forman fases líquido-cristalinas estables. Estos anfífilos intrínsecamente interconectados mantienen su estructura después de la fotoconexión, ofreciendo una mayor estabilidad térmica.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química supramolecular de las moléculas.
- Química de Polímeros La Química de Polímeros es la química de los polímeros.
Sus antecedentes:
- Los tensioactivos Gemini ofrecen propiedades únicas debido a su doble cola hidrofóbica y cabeza hidrofílica.
- Las fases litotrópicas líquido-cristalinas (LLC, por sus siglas en inglés) son estructuras ordenadas formadas por anfifiles en solución.
- Las anfifilas de enlaces cruzados pueden mejorar la estabilidad y las propiedades de sus mesofasas.
Objetivo del estudio:
- Para sintetizar y caracterizar surfactantes gemini intrínsecamente entrelazados.
- Para investigar el comportamiento de la fase líquido-cristalina liotrópica de estos nuevos anfífilos.
- Explorar el fotoenlace de estos tensioactivos y la estabilidad de los materiales resultantes.
Principales métodos:
- Síntesis de anfifiles de fosfonio gemini basados en bis ((alquilo-1,3-dieno).
- Estudios de comportamiento de la fase líquido-cristalina liotrópica en el agua.
- Fotoenlace cruzado de las fases de LLC utilizando espectrometría UV-vis.
- Difracción de rayos X en polvo para el análisis estructural.
- Pruebas de estabilidad térmica de materiales entrelazados.
Principales resultados:
- Los tensioactivos gemini formaron las fases hexagonales (H) (I), cúbicas (Q) (I) y lamelares (L) (alfa).
- El photocross-linking mantuvo la arquitectura de fase de todas las fases de LLC observadas.
- El grado de polimerización osciló entre el 23% y el 71%, lo que garantiza la estabilización del sistema.
- Las fases entrelazadas exhibieron una notable estabilidad térmica hasta 300°C en el aire.
Conclusiones:
- Estos representan los primeros surfactantes gemini polimerizables y los primeros anfífilos de enlace cruzado polimerizados tanto en mesofasas hexagonales como en mesofasas cúbicas.
- El enfoque de fotoenlace cruzado estabiliza efectivamente las microestructuras de LLC.
- Los materiales resultantes muestran un potencial significativo para aplicaciones que requieren una alta estabilidad térmica.
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