Deformation of a Liquid Near an AFM Tip: Molecular Dynamics Approach.
Deformation of a Liquid Near an AFM Tip: Molecular Dynamics Approach.
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AFM 尖端附近液体的变形：分子动力学方法。
DOI：
10.1021/acs.langmuir.0c00023
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
J. Dufrêche
中科院分区：
文献类型：
--
作者：
Lolita Hilaire;B. Siboulet;R. Ledesma;D. Legendre;P. Tordjeman;S. Charton;J. Dufrêche
利用分子动力学方法研究了原子力显微镜探针与沉积在平面衬底上的水薄膜之间的相互作用。研究了薄膜厚度和探针半径对液体界面变形高度和液体与探针直接接触时的跳跃距离的影响。详细研究了表面变形的动力学和界面波动的作用。所考虑的系统属于Ledesma\textit{等}人先前建立的半解析模型中描述的薄膜体系（Langmuir \textbf{2013,29}, 7749-7757）。MD模拟预测，对于浅膜，无论探针半径如何，跳跃到接触的距离和表面最大变形高度都随着层厚度的增加而稳定增加，这与先前提出的理论模型一致。由于热波动的强烈影响，表面的变形是不稳定的。对于所考虑的每个系统，薄膜厚度都是这样的，界面波动引起了接触的跳跃。通过与连续模型预测的变形曲线的比较，指出了两种方法的互补性。分子方法的结果不仅与连续模型的结果一致，而且还为纳米尺度现象的描述提供了更多的信息。特别是，MD的结果指出了波动在描述涉及软界面的纳米系统的特定动力学时的重要性。这表明需要改进连续模型，通过分子方法来补充它们以获得更好的准确性。
The interaction between an AFM probe and a thin film of water deposited over a flat substrate is studied using Molecular Dynamics (MD). The effects of the film thickness and of the probe radius on both the deformation height of the liquid interface, and the distance of the jump to contact at which the liquid comes in direct contact with the probe, are investigated. The dynamics of the surface deformation and the role of interface fluctuations are studied in details. The systems considered belong to the thin film regime described in a semi-analytical model previously established by Ledesma \textit{et al.} (Langmuir 2013, \textbf{29}, 7749-7757). MD simulations predict that for shallow films, both the distance at which the jump to contact occurs, and the surface maximal deformation height increase steadily with the layer thickness regardless of the probe radius, which is in agreement with the previously proposed theoretical model. The deformation of the surface was shown to be unstable due to the strong effect of thermal fluctuations. For each of the considered systems, the film thickness was such that interface fluctuations induced the jump to contact. The comparison of the deformation obtained in MD with the profiles predicted by the continuous model points out the complementarity between the two approaches. The results of the molecular approach are not only consistent with those of the continuous model, they also provide more information on the description of nano-scale phenomena. In particular, MD results points out the importance of fluctuations when it comes to the description of the particular dynamics of nanosystems involving soft interfaces. This shows the need to improve continuous models by complementing them with a molecular approach for a better accuracy.
影响因子：
8.6
作者：
Berg, John K.;Weber, Constans M.;Riegler, Hans
通讯作者：
Riegler, Hans