Constant Number Density of Liquid Inclusions Formed in Frozen Aqueous Electrolyte
Constant Number Density of Liquid Inclusions Formed in Frozen Aqueous Electrolyte
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冷冻水电解质中形成的液体包裹体的恒定数密度
DOI：
10.1002/cphc.201300380
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发表时间：
2013
期刊：
影响因子：
2.9
通讯作者：
and Tetsuo Okada
中科院分区：
文献类型：
--
作者：
Takuya Hashimoto;Makoto Harada;Shuichi Nojima;and Tetsuo Okada
用共聚焦荧光显微镜和小角度X射线散射（SAXS）对冷冻氯水溶液（≤50 mM）进行了表征。前一种方法使我们能够确定在高于系统共晶点（teu）的温度下冰基体中形成的液体包裹体的大小。当冷冻电解质的温度升高时，形成大小均匀的孤立的液体包体。液体包裹体的大小取决于观察温度以及溶解在原始未冷冻溶液中的盐的浓度（csalt）和类型。然而，液体包裹体的数量密度几乎是恒定的，与这些实验参数无关，特别是当电解质被冷冻在液氮中时。然后，在冰晶的缺陷处就会出现盐的积累。缺陷的发生概率与掺入盐的性质无关。根据盐的不同，每个包合物中盐的含量在7到240 fmol之间。SAXS测量提供了在温度低于10℃时形成的单个盐晶体大小的信息。盐晶体的旋转半径在2 ~ 2.8 nm之间，对盐的影响不大。因此，每个内含物都是由106 - 109纳米晶体组成的，这些纳米晶体可以作为种子。当在更高的温度下制备掺杂冰时，例如- 16℃，液体包裹体的隔离是不够的，在温度或盐的升高时更容易发生聚结。然而，当盐度低于10 mM时，无论冻结温度如何，液体包裹体的数量密度几乎不变。
Frozen aqueous chlorides (≤50 mM) are characterized by using confocal fluorescence microscopy and small angel X‐ray scattering (SAXS). The former method allows us to determine the size of a liquid inclusion formed in the ice matrix at temperatures above the eutectic point of the system (teu). Isolated liquid inclusions of a uniform size are formed when the temperature of a frozen electrolyte increases pastteu. The size of the liquid inclusions depends on the observation temperature as well as on the concentration (csalt) and type of salt dissolved in the original unfrozen solution. However, the number density of liquid inclusions is almost constant and independent of these experimental parameters, particularly when an electrolyte is frozen in liquid nitrogen. Salt accumulation can then occur at the imperfections of the ice crystals. The occurrence probability of the imperfections is independent of the nature of an incorporated salt. The amount of a salt confined in each inclusion ranges from 7 to 240 fmol, depending oncsalt. SAXS measurements provide information on the size of individual salt crystals formed at temperatures belowteu. The radius of gyration of a salt crystal ranges from 2 to 2.8 nm, and does not depend significantly oncsalt. Thus, each inclusion is formed from 106–109nanocrystals, which can act as seeds. When doped ice is prepared at higher temperatures, for example −16 °C, the isolation of liquid inclusions is not sufficient and coalescence occurs more easily upon an increase in temperature orcsalt. However, whencsaltis lower than 10 mM, the number density of liquid inclusions is almost constant, irrespective of the freezing temperature.