Interfacial flows in sessile evaporating droplets of mineral water.
Interfacial flows in sessile evaporating droplets of mineral water.
复制标题
矿泉水固着蒸发液滴中的界面流动
DOI：
10.1103/physreve.100.033103
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
C. J. Kähler
中科院分区：
文献类型：
--
作者：
M. Rossi;A. Marin;C. J. Kähler
固相超纯水蒸发液滴中的液体流动通常由两个主要因素引起：一种是毛细管流将液体从主体推向接触线，另一种是热Marangoni流将液滴自由表面推向顶端。目前的分析和数值模型与实验观测定性吻合较好，但它们高估了两到三个数量级的界面速度值。这种差异通常归因于水样受到不溶表面活性剂的污染；然而，这一假设尚未得到实验证实。在这项工作中，我们证明了一个小的“离子污染”可以导致显著影响液滴内部的流动模式。为了提供证据，我们比较了不同矿化度的商用瓶装水和超纯水蒸发水滴中的流动。矿泉水是在天然泉水中装瓶的，具有微生物纯度，只含有微量的矿物质(以及其他可能的污染物)，因此人们预计，随着“污染物”数量的增加，界面流动会变慢。令人惊讶的是，我们的结果表明，对于低矿物含量的矿泉水，界面流动的大小实际上与超纯水的相同。然而，对于矿物质含量较大的水，由于离子浓度梯度的存在，界面流动往往会变慢。我们的结果显示了一个比通常所怀疑的要复杂得多的场景，因此有必要对数值模型和实验之间的巨大差异进行更深入和更全面的分析。
Liquid flow in sessile evaporating droplets of ultrapure water typically results from two main contributions: a capillary flowpushingthe liquid toward the contact line from the bulk and a thermal Marangoni flowpullingthe drop free surface toward the summit. Current analytical and numerical models are in good qualitative agreement with experimental observations; however, they overestimate the interfacial velocity values by two to three orders of magnitude. This discrepancy is generally ascribed to contamination of the water samples with nonsoluble surfactants; however, an experimental confirmation of this assumption has not yet been provided. In this work, we show that a small “ionic contamination” can cause a significant effect in the flow pattern inside the droplet. To provide the proof, we compare the flow in evaporating droplets of ultrapure water with commercially available bottled water of different mineralization levels. Mineral waters are bottled at natural springs, are microbiologically pure, and contain only traces of minerals (as well as traces of other possible contaminants), and therefore one would expect a slower interfacial flow as the amount of “contaminants” increase. Surprisingly, our results show that the magnitude of the interfacial flow is practically the same for mineral waters with low content of minerals as that of ultrapure water. However, for waters with larger content of minerals, the interfacial flow tends to slow down due to the presence of ionic concentration gradients. Our results show a much more complex scenario than it has been typically suspected and therefore a deeper and more comprehensive analysis of the huge differences between numerical models and experiments is necessary.
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影响因子：
3.4
作者：
Bodiguel, Hugues;Leng, Jacques
通讯作者：
Leng, Jacques
DOI：
10.1021/issn.1520-6106
发表时间：
--
期刊：
--
影响因子：
--
作者：
通讯作者：
--
影响因子：
2.7
作者：
Marin, Alvaro;Karpitschka, Stefan;Rodriguez Valverde, Miguel A.
通讯作者：
Rodriguez Valverde, Miguel A.
DOI：
--
发表时间：
2018
期刊：
Colloids and Surfaces B: Biointerfaces
影响因子：
--
作者：
M. Ríos;A. D. Reyes;J. Ruiz;J. González
通讯作者：
J. González
影响因子：
2.4
作者：
Cierpka, C.;Rossi, M.;Kaehler, C. J.
通讯作者：
Kaehler, C. J.