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Promoción de la nucleación de hielo homogéneo por moléculas solubles

Kenji Mochizuki^1,2, Yuqing Qiu¹, Valeria Molinero¹

¹Department of Chemistry, The University of Utah , Salt Lake City, Utah 84112-0580, United States.

Journal of the American Chemical Society

|November 8, 2017

Resumen

Las moléculas solubles flexibles como el alcohol polivinílico (PVA) promueven inesperadamente la nucleación de hielo. Las simulaciones moleculares revelan que el PVA desestabiliza el agua, mejorando la formación de cristales de hielo a través de un mecanismo homogéneo, ofreciendo nuevas estrategias de diseño para los aditivos de cristalización.

Área de la Ciencia:

Ciencias atmosféricas
Física y química
Ciencias de los materiales

Sus antecedentes:

La nucleación de hielo en las nubes tiene un impacto significativo en la precipitación y el clima.
La nucleación de hielo heterogéneo en las superficies de partículas es el mecanismo ampliamente aceptado.
Se ha observado que las moléculas solubles como el alcohol polivinílico (PVA) aumentan las temperaturas de congelación del hielo, desafiando las teorías existentes.

Objetivo del estudio:

Investigar el mecanismo por el cual las moléculas solubles flexibles, como el PVA, promueven la nucleación de hielo.
Para entender cómo estas moléculas, que carecen de una superficie definida, facilitan la formación de cristales de agua.
Para explorar un nuevo paradigma para la nucleación de hielo por aditivos solubles.

Principales métodos:

Se emplearon simulaciones moleculares para estudiar la interacción entre PVA y agua.
Se analizó la tasa de nucleación del hielo en presencia de PVA.
Se investigó el efecto del PVA en la estabilidad del agua en solución.

Principales resultados:

Se demostró que el alcohol polivinílico (PVA) promueve la nucleación de hielo a través de un mecanismo homogéneo.
El PVA aumenta la tasa de nucleación del hielo al desestabilizar las moléculas de agua en la solución.
Este hallazgo contrasta con la teoría predominante de la nucleación heterogénea.

Conclusiones:

Las moléculas solubles pueden promover la nucleación de hielo a través de la desestabilización homogénea del agua.
Este estudio presenta un nuevo paradigma para comprender la nucleación del hielo mediante aditivos solubles.
Los hallazgos proporcionan información para el diseño de nuevos aditivos para controlar los procesos de cristalización.

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