Effect of electric field on water free energy in graphene nanochannel
Effect of electric field on water free energy in graphene nanochannel
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DOI：
10.1063/5.0080876
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发表时间：
2022-07
影响因子：
3.2
通讯作者：
Dezhao Huang;Shiwen Wu;Guoping Xiong;T. Luo
中科院分区：
文献类型：
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作者：
Dezhao Huang;Shiwen Wu;Guoping Xiong;T. Luo
石墨烯纳米通道和纳米结构已经对诸如纳米流体和太阳能热蒸发的应用产生了极大的兴趣，因为纳米限制可以导致改变的液体性质。在这篇文章中，我们采用分子动力学模拟结合自由能微扰法研究了外电场对石墨烯纳米通道中水分子自由能的影响。我们观察到随着电场的增加，水自由能差（[公式：见正文]，其中0是参考真空状态，1是溶剂化状态）减小，这表明电场的应用可以减少从石墨烯纳米通道蒸发水所需的热能。我们的分析表明，在自由能差的减少有关的更多的水分子沿沿着电场方向在纳米通道，这导致在水分子间的势能降低，从而减少自由能差。
Graphene nanochannels and nanostructures have been of great interest to applications like nanofluidics and solar-thermal evaporation since nanoconfinement can lead to altered liquid properties. In this article, we employ molecular dynamics simulations combined with the free energy perturbation method to study the influence of external electric fields on the free energy of water molecules in graphene nanochannels. We observe a decrease in the water free energy difference ([Formula: see text], where 0 is the reference vacuum state and 1 is the solvated state) with the increasing electric field, suggesting that the application of an electric field may reduce the thermal energy needed to evaporate water from graphene nanochannels. Our analysis reveals that the reduction in free energy difference is related to more aligned water molecules along the electric field direction in the nanochannels, which leads to a decrease in the water inter-molecular potential energy and, thus, reduces the free energy difference.