Ripening and recrystallization of NaCl nanocrystals in humid conditions
Ripening and recrystallization of NaCl nanocrystals in humid conditions
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DOI：
10.1039/c5ra22425j
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发表时间：
2016-01
期刊：
影响因子：
3.9
通讯作者：
M. Oliva‐Ramírez;M. Macias‐Montero;A. Borrás;A. Gonzalez-Elipe
中科院分区：
文献类型：
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作者：
M. Oliva‐Ramírez;M. Macias‐Montero;A. Borrás;A. Gonzalez-Elipe
这项研究表明，奥斯特瓦尔德成熟是一种导致溶液沉淀过程中晶体尺寸增加的普遍机制，可以通过离子扩散穿过连接分离纳米晶体的凝聚单层水来调节。在环境电子显微镜中，我们已经观察到“原位”的时间演化的数量，形状，尺寸和晶体结构的NaCl纳米粒子沉积的电子束蒸发在倾斜的角度。水蒸气冷凝前后的NaCl纳米颗粒的分析表明，纳米晶体的尺寸不是诱导纳米颗粒成熟和再结晶的唯一驱动力，但其结晶习性的刻面和最初沉积的核的非晶化程度也起着重要的作用。这些发现对其他结晶和成核过程有影响，并可能与岩石风化和相关现象有关。
This study shows that Ostwald ripening, a universal mechanism responsible for the increase of crystal size during precipitation from solutions, can be meditated by ion diffusion through condensed monolayers of water that connect separated nanocrystals. In an environmental electron microscope we have observed “in situ” the time evolution of the number, shape, size and crystallographic texture of NaCl nanoparticles deposited by electron beam evaporation at oblique angles. Analysis of NaCl nanoparticles before and after water vapor condensation has evidenced that the size of nanocrystals is not the unique driving force inducing nanoparticle ripening and recrystallization, but the faceting of their crystalline habits and the amorphisation degree of the initially deposited nuclei also play important roles. These findings have implications for other crystallization and nucleation processes and can be of relevance for rock weathering and related phenomena.