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Aclarar el comportamiento de la transición vítrea del agua en comparación con los vasos inorgánicos hipercalentados
Yuanzheng Yue1, C Austen Angell
1Section of Chemistry, Department of Life Sciences, Aalborg University, DK-9000 Aalborg, Denmark.
Nature
|February 20, 2004
Resumen
Agua Agua Agua Agua Agua Agua Agua
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química Física es la química física.
- La termodinámica es la termodinámica.
Sus antecedentes:
- La formación de vidrio es común para líquidos con amplios rangos de líquidos o enfriamiento rápido.
- Las sustancias exhiben comportamientos distintos al recalentarse: los buenos formadores de vidrio pasan a líquidos súper enfriados, mientras que otros se cristalizan.
- La transición vítrea del agua ha sido debatida durante décadas, con una transición ampliamente aceptada pero anómala a 136 K.
Objetivo del estudio:
- Para investigar el comportamiento de los vasos inorgánicos hipercalentados durante el recalentamiento.
- Para comparar las propiedades térmicas de los vidrios inorgánicos con las del agua vidriosa.
- Reevaluar la naturaleza y la existencia de la transición del agua al vidrio.
Principales métodos:
- Caracterizaciones calorimétricas detalladas de vidrios inorgánicos hipercalentados.
- Experimentos de calentamiento en vidrios inorgánicos para observar las transiciones antes de la cristalización.
- Análisis comparativo de datos térmicos entre vidrios inorgánicos y agua vidriosa.
Principales resultados:
- Los vidrios inorgánicos hiperapagados no se cristalizan antes de alcanzar sus temperaturas de transición de vidrio.
- Los efectos térmicos observados en el agua vidriosa son análogos a las "sombras" de una verdadera transición de vidrio.
- La transición ampliamente aceptada de 136 K en el agua no es la transición primaria de vidrio.
Conclusiones:
- La transición directa al vidrio del agua no puede ser probada experimentalmente bajo condiciones típicas.
- Una verdadera transición de vidrio para el agua probablemente ocurra a temperaturas más altas, enmascarada por la cristalización.
- El comportamiento anómalo de la transición de 136 K del agua se explica por ser un efecto secundario.
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