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Un cocristal de diarileteno que convierte la luz en trabajo mecánico
Masakazu Morimoto1, Masahiro Irie
1Department of Chemistry and Research Center for Smart Molecules, Rikkyo University, Nishi-Ikebukuro 3-34-1, Toshima-ku, Tokyo 171-8501, Japan.
Journal of the American Chemical Society
|September 23, 2010
Resumen
Este estudio muestra un cocristal fotocrómico que se dobla de manera reversible con los rayos UV y la luz visible. Estos cristales moleculares pueden levantar objetos pesados, generando una tensión mecánica significativa.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- La cristalografía es una técnica de cristalografía.
- La fotoquímica es la fotoquímica.
Sus antecedentes:
- Los materiales fotocrómicos cambian de color al exponerse a la luz.
- Los cristales moleculares ofrecen propiedades mecánicas únicas.
- Los derivados del diarileteno son conocidos por su comportamiento fotocrómico.
Objetivo del estudio:
- Para investigar el efecto fotomecánico de un nuevo cocristal de diarilethene-perfluoronaphthalene.
- Para caracterizar el movimiento de flexión reversible y su mecanismo subyacente.
- Para explorar las posibles aplicaciones de este material en actuadores moleculares.
Principales métodos:
- Síntesis y caracterización del cocristal de 1,2-bis-metil-5-naftil-3-tienile-perfluorociclopenteno (1o) y perfluoronaftaleno (FN).
- Análisis cristalográfico de rayos X in situ para estudiar la deformación de los cristales.
- Pruebas mecánicas de los cantilevers de cristales moleculares.
- Mediciones dinámicas a baja temperatura del movimiento de flexión.
Principales resultados:
- El cocristal 1o·FN exhibe una curvatura reversible tras la irradiación alterna de UV y luz visible, repetible durante 250 ciclos.
- La deformación cristalina se atribuye a la elongación del eje b causada por la fotociclización del diarileto.
- El movimiento de flexión se produce incluso a 4.7 K con expansión anisotrópica en la escala de tiempo de microsegundos.
- Los voladizos de cristal molecular pueden levantar objetos de 200 a 600 veces su peso.
- La tensión generada alcanza los 44 MPa, comparable a los materiales piezoeléctricos.
Conclusiones:
- El cocristal diarilethene-perfluoronaphthalene demuestra propiedades fotomecánicas significativas.
- El material exhibe una curvatura inducida por la luz y un trabajo mecánico eficientes y repetibles.
- Esta investigación abre caminos para el desarrollo de máquinas moleculares avanzadas y actuadores.
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