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 力学学报  2016, Vol. 48 Issue (3): 714-719  DOI: 10.6052/0459-1879-15-426 0

### 引用本文 [复制中英文]

[复制中文]
Luo Qingqun, Yang Jieming. HYDROPHOBIC ATTRACTION OF GRAPHENE IN LIQUIDWATER WITH AND WITHOUT GAS[J]. Chinese Journal of Theoretical and Applied Mechanics, 2016, 48(3): 714-719. DOI: 10.6052/0459-1879-15-426.
[复制英文]

### 文章历史

2015-11-25 收稿
2016-01-04 录用
2016-01-14 网络版发表.

1 模 拟

1.1 理论依据

1.2 初始模型

 图1 分子动力学模拟的初始模型 Figure.1 View of the simulation system

1.3 模拟步骤

2 分析与讨论 2.1 没有气体溶解的情况

 图2 初始构象和部分中间构象图及其对应的水密度分布 Figure.2 Water densities and corresponding configurations at different

 图3 没有气体溶解的情况，两片石墨烯在水中相互作用的平均力势曲线 Figure.3 The calculated PMF curve for two pieces of graphene in the expansion without gas phase
2.2 有气体溶解的情况

 图4 不同距离的构象和对应的气体密度分布 Figure.4 Gas densities and corresponding configurations at different distances

 图5 纳米气泡桥形成/消失过程的示意图 Figure.5 Diagram of formation/disappearance of nanobubble bridge

 图6 有气体溶解的情况，两片石墨烯在水中相互作用的平均力势曲线 Figure.6 The calculated PMF curve for two pieces of graphene in the expansion with gas phase
3 讨 论

1)当石墨烯间距小于0.5nm时，无论水中是否溶解有气体疏水引力都是由真空纳米气泡桥引起的，这个结论与相关研究结果基本一致[31].

(2)当石墨烯间距大于0.5nm时，没有气体溶解的水中，疏水引力是由水蒸气纳米气泡桥引起的；而在有气体溶解的水中疏水引力是由所溶气体纳米气泡桥引起的.

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HYDROPHOBIC ATTRACTION OF GRAPHENE IN LIQUIDWATER WITH AND WITHOUT GAS
Luo Qingqun, Yang Jieming
Taiyuan University of Technology, Key Laboratory Advanced Transducers and Intelligent Control System, Ministry of Education, Taiyuan 030024, China
Abstract: The phenomenon that the gas dissolved in water can be adsorbed and accumulated on the hydrophobic surface is discovered by condensed matter physics. Thus, when the distance between the hydrophobic objects is small enough, the gases adsorbed on the hydrophobic surfaces will connect each other and form nanobubble bridges. The nanobubble bridges cause hydrophobic attraction. However, the formation/disappearance process and the morphology of nanobubble bridges have not been provided in academe of mechanics. In this article, the interactions of a pair of graphene in liquid water with and without gas phase are studied using molecular simulation. The changes of structural phase diagram and potential of mean force of the system, the density distribution of gas and water were analyzed. The results show that the hydrophobic attraction of two pieces of graphenes is really caused by the nanobubble bridge. When the distance between the pair of graphenes is less then approximate 0.5 nm, hydrophobic attraction is led by vacuum nanobubble bridge no matter with or without gas phase in water. When their distance is greater than approximate 0.5 nm, the hydrophobic attraction without gas in water is led by the nanobubble bridge of vapor, and the hydrophobic attraction with gas in water is led by the nanobubble bridge of the gas.
Key words: hydrophobic interaction    nanobubble bridge of vapor    molecular dynamics    nanobubble bridge