The anomalously high melting temperature of bilayer ice
The anomalously high melting temperature of bilayer ice
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DOI：
10.1063/1.3368793
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发表时间：
2010-03-28
影响因子：
4.4
通讯作者：
Molinero, Valeria
中科院分区：
文献类型：
--
作者：
Kastelowitz, Noah;Johnston, Jessica C.;Molinero, Valeria
水的限制通常降低其熔化温度。在这里，我们使用分子动力学模拟来确定液晶平衡温度的水限制在平行的疏水性或轻度亲水性板之间的表面之间的距离的函数。我们发现，双层冰，冰的多晶型体，其中每个水分子的局部环境强烈偏离最稳定的四面体结构，具有最高的熔化温度（Tm）的一系列的L-层冰。双层冰的融化温度不仅比其他受限冰高得多，而且还高于大块六边形冰的熔点。最近的力显微镜实验的水限制在石墨和钨尖揭示了冰的形成在室温下[K。B。Jinesh和J. W. M. Frenken，Phys. Rev. Lett. 101，036101（2008）]。我们的研究结果表明，双层冰，我们计算的T-M高达310 K的疏水限制，是在这些实验中形成的晶体。
Confinement of water usually depresses its melting temperature. Here we use molecular dynamics simulations to determine the liquid-crystal equilibrium temperature for water confined between parallel hydrophobic or mildly hydrophilic plates as a function of the distance between the surfaces. We find that bilayer ice, an ice polymorph in which the local environment of each water molecule strongly departs from the most stable tetrahedral structure, has the highest melting temperature (T-m) of the series of l-layer ices. The melting temperature of bilayer ice is not only unusually high compared to the other confined ices, but also above the melting point of bulk hexagonal ice. Recent force microscopy experiments of water confined between graphite and a tungsten tip reveal the formation of ice at room temperature [K. B. Jinesh and J. W. M. Frenken, Phys. Rev. Lett. 101, 036101 (2008)]. Our results suggest that bilayer ice, for which we compute a T-m as high as 310 K in hydrophobic confinement, is the crystal formed in those experiments.