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Fases giroideas liotrópicas acuosas inusualmente estables de los tensioactivos dicarboxilato de gemini
Gregory P Sorenson1, Keiva L Coppage, Mahesh K Mahanthappa
1Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
Journal of the American Chemical Society
|September 6, 2011
Resumen
Los nuevos tensioactivos aniónicos de forma inesperada forman fases de cristales líquidos giróideos estables. Este descubrimiento ofrece una nueva estrategia de diseño para materiales avanzados con morfologías cúbicas bicontinuas.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química supramolecular de las moléculas.
- Ciencia de la coloide Ciencia de las coloides.
Sus antecedentes:
- Los cristales líquidos liotrópicos acuosos (CLL) con cubo bicontinuo (fases Q) son prometedores para las separaciones y el transporte de iones.
- Actualmente faltan reglas de diseño universal para anfifiles que forman fases Q.
- Los tensioactivos catiónicos gemini muestran una tendencia a la formación de la fase Q, pero esto no está universalmente establecido.
Objetivo del estudio:
- Investigar el potencial de los tensioactivos aniónicos gemini en la formación de LLCs cúbicas bicontinuas estables.
- Establecer criterios de diseño para anfifiles que favorezcan la formación de la fase Q.
- Para explorar la influencia de la estructura molecular en la morfología LLC.
Principales métodos:
- Síntesis modular de nuevos tensioactivos aniónicos gemini a partir de ácidos carboxílicos alifáticos.
- Variación sistemática de la longitud del espaciador de alquilo y de los contornos del tensioactivo (Na+, K+, (CH3) 4N+).
- Caracterización de las fases de cristales líquidos formados a través de un rango de temperaturas y concentraciones.
Principales resultados:
- Los tensioactivos aniónicos Gemini demostraron una fuerte propensión a formar fases LLC de la tiroides.
- Estas fases de tiroides exhibieron una estabilidad sin precedentes de 25 a 100 °C.
- Se observó la formación estable de la fase Q en amplias ventanas de concentración anfífila (hasta un 20 por ciento en peso).
Conclusiones:
- Los tensioactivos aniónicos gemini son efectivos para estabilizar las morfologías de LLC cúbicas bicontinuas tecnológicamente relevantes.
- El diseño molecular, específicamente la longitud del espaciador de alquilo y la elección del contrarión, influye significativamente en la formación de la fase Q.
- Este trabajo proporciona información clave sobre el diseño de anfifiles para fases estables de cristales líquidos cúbicos bicontinuos.
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