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Deformación inducida por compresión de cada uno de los microcristales de marco metálico-orgánico
Zhi Su1, Yu-Run Miao, Shi-Min Mao
1Department of Chemistry and ‡Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
Journal of the American Chemical Society
|January 31, 2015
Resumen
Los microcristales de marco de imidazolato zeolítico (ZIF-8) experimentan una reducción significativa de volumen y amorfización bajo presión. Los solvantes alteran drásticamente las propiedades mecánicas de ZIF-8, haciéndolos menos deformables y propensos a romperse.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Nanotecnología La nanotecnología es la nanotecnología.
- Ingeniería Química Ingeniería Química.
Sus antecedentes:
- Las estructuras de zeolítico-imidazolato (ZIF) son una clase de estructuras metal-orgánicas conocidas por sus estructuras y aplicaciones sintonizables.
- Comprender las propiedades mecánicas de los ZIF a microescala es crucial para su uso en diversas aplicaciones de ingeniería.
- ZIF-8, un miembro prominente de esta clase, exhibe características estructurales y químicas únicas.
Objetivo del estudio:
- Investigar la deformación y el comportamiento mecánico de los micro y submicrocristales individuales de marco de imidazolato zeolítico (ZIF-8) bajo compresión.
- Para determinar el módulo de Young y los cambios de volumen en función de la presión aplicada a los cristales individuales ZIF-8.
- Explorar la influencia de los solvados, el tamaño y la orientación en las propiedades mecánicas de los cristales ZIF-8.
Principales métodos:
- Experimentos de compresión en micro y submicrocristales individuales ZIF-8.
- Medición de los cambios en el módulo de Young y el volumen bajo presión variable.
- Investigación del comportamiento de los cristales (deformación, amorfización, recuperación) hasta 4 GPa.
- Análisis de los efectos del solvado, el tamaño y la orientación en la respuesta mecánica.
Principales resultados:
- Los microcristales individuales ZIF-8 exhibieron drásticas disminuciones de volumen y amorfización bajo compresión (0-4 GPa).
- Los microcristales ZIF-8 deformados mostraron una recuperación parcial del volumen después de la liberación de presión.
- Los microcristales ZIF-8 solvados con metanol fueron significativamente menos deformables y se rompieron fácilmente en comparación con los cristales desolvados.
- La orientación y el tamaño influyeron en el comportamiento mecánico de los nano y microcristales ZIF-8.
Conclusiones:
- El comportamiento mecánico de los cristales ZIF-8 depende en gran medida de su morfología, tamaño y presencia de solvados.
- La compresión conduce a cambios estructurales significativos, incluida la amorfización, en los microcristales ZIF-8.
- El estado de solvación juega un papel crítico en la determinación de la integridad mecánica y la deformabilidad de los cristales simples ZIF-8.
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