从分子角度看,超冷滴中的冰结晶动力学从分子角度看
Khadije El Kadi1, Sohail Murad2, Isam Janajreh1
1Mechanical and Nuclear Engineering Department, Khalifa University, Abu Dhabi, United Arab Emirates; Center for Membrane and Advanced Water Technology, Khalifa University, Abu Dhabi, United Arab Emirates.
Journal of colloid and interface science
|October 16, 2025
概括
研究自由悬浮的水滴揭示了大小,盐度和冷却速度极大地影响冰核形成. 盐度和快速冷却抑制了冰的形成,而较慢的冷却增强了它,影响了冷淡化和冷保存.
科学领域:
- 物理化学 物理化学
- 材料科学 材料科学 材料科学
- 热力学是一种热力学.
背景情况:
- 超冷水中的冰核化对于冷淡化,冷保存和大气科学至关重要.
- 之前的研究集中在散装或基板绑定系统上,限制了对内在结行为的理解.
- 这项研究检查了纳米和微尺度的自由悬浮滴,以隔离基本的冰形成过程.
研究的目的:
- 为了研究水滴大小,盐度和冷却速度对冰核热力学和运动学的影响.
- 为了区分纳米和微尺度自由悬浮的水滴之间的结行为.
- 阐明与各种应用相关的超冷水中冰形成的机制.
主要方法:
- 在0-70g/L的盐度范围内对自由悬浮的微升滴 (0.5-3.5μL) 进行实验性研究.
- 在不同的条件下,纳米级滴滴 (5.04-9.54 nm) 的详细分子动力学 (MD) 模拟.
- 在模拟中,滴滴大小,盐度和冷却速度 (0.1-10,000 K/ns) 的系统变化.
主要成果:
- 实验显示了两阶段的结过程 (带有回收的树突生长,然后是体积生长).
- 模拟MD显示单阶段结纳米滴,与较慢的冷却增加核化率50%和快速冷却诱导玻璃化.
- 盐度降低了核化率 (39-56%) 和回收率 (高达44%),而在接口上的离子聚类改变了水的结构并促进了异质性.
结论:
- 滴滴大小,盐度和冷却速度是调节超冷水中的冰核形成路径的关键因素.
- 界面离子分布,离子聚类和尺寸依赖的限制显著影响冰的形成机制.
- 这些发现有助于在与海水淡化,冷保存和大气科学相关的系统中进一步了解冰的形成机制.
相关概念视频
Crystal Growth: Principles of Crystallization
4.7K
Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
4.7K
Recrystallization: Solid–Solution Equilibria
2.2K
Recrystallization is a purification technique used to separate impurities from solid compounds. In this technique, no chemical reactions occur. Instead, it exploits physical properties only, specifically, the solubility differences between the desired compound and impurities, either at a single temperature or at different temperatures, and under other selected conditions. The solid-solution equilibrium (solubility equilibrium) of each component in the solution represents a binary phase...
2.2K
Phase Transitions: Melting and Freezing
14.6K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
14.6K
Phase Transitions: Vaporization and Condensation
20.5K
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
20.5K
Precipitation Processes
4.8K
The experimental conditions in a gravimetric analysis should be optimized to maximize the particle size and purity of the obtained precipitate. Ideally, the concentration of the precipitating reagent should be low with effective stirring to maintain low relative supersaturation for the growth of large crystals. In homogeneous precipitation, the precipitant is slowly generated by a chemical reaction in the solution to avoid local reagent excesses. For example, urea decomposes gradually to...
4.8K
States of Water
56.0K
Water exists in any one of the three classical states: solid (ice), liquid (water), and gas (steam or water vapor). The state of water depends on i) the intermolecular forces that draw molecules together and ii) the kinetic energy that leads to movements that pull them apart.
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
56.0K


