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Líquidos isotrópicos quirales de las moléculas achirales
L E Hough1, M Spannuth, M Nakata
1Department of Physics and Liquid Crystal Materials Research Center, University of Colorado, Boulder, CO 80309, USA. hough@colorado.edu
Science (New York, N.Y.)
|July 25, 2009
Resumen
Las moléculas simples de núcleo doblado forman fases únicas de cristales líquidos. A pesar de ser achirales, estas fases exhiben una quiralidad espontánea y un alto poder rotatorio óptico debido a la inestabilidad de la capa.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Física de la materia condensada Física de la materia condensada
- Química Química es la química.
Sus antecedentes:
- Las moléculas de núcleo doblado pueden formar fases de cristal líquido con propiedades únicas.
- Los cristales líquidos sméticos suelen exhibir capas de fluido plano.
- La polarización espontánea y la quiralidad son inusuales en las moléculas achirales.
Objetivo del estudio:
- Para investigar las fases de los cristales líquidos formados por moléculas simples de núcleo doblado.
- Comprender el origen de la polarización espontánea y la quiralidad en estas fases.
- Para caracterizar la estabilidad y la ruptura de simetría en estos sistemas moleculares.
Principales métodos:
- Síntesis y caracterización de moléculas de núcleo doblado.
- Microscopía y difracción de rayos X para estudiar las fases de cristales líquidos.
- Mediciones ópticas para determinar la potencia rotatoria.
Principales resultados:
- Las moléculas de núcleo doblado forman fases de cristales líquidos smecticos con capas de fluido plano.
- La falta de coincidencia estructural dentro de la capa lleva a la inestabilidad contra la deformación de la empalme del sillín.
- Se forman fluidos isotrópicos macroscópicos con orden de corto alcance y quiralidad espontánea.
- Se observaron altas potencias rotatorias ópticas en dominios conglomerados.
Conclusiones:
- Las moléculas de núcleo doblado pueden exhibir quiralidad y polarización espontáneas sin orden cristalino.
- La inestabilidad de la capa dicta las propiedades macroscópicas, lo que lleva a fluidos isotrópicos con simetría rota.
- Estos hallazgos ofrecen nuevos conocimientos sobre la relación entre la estructura molecular y las propiedades macroscópicas en cristales líquidos.
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