How Small Is Too Small for the Capillarity Theory?
How Small Is Too Small for the Capillarity Theory?
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DOI：
10.1021/acs.jpcc.0c11140
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发表时间：
2021-03-02
影响因子：
3.7
通讯作者：
Giovambattista, Nicolas
中科院分区：
文献类型：
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作者：
Almeida, Alexandre B.;Buldyrev, Sergey, V;Giovambattista, Nicolas
我们进行分子动力学（MD）模拟纳米级水毛细桥（WCBs）在两个平行的墙壁之间扩展，并确定最小的分离以上的毛细理论（CT）仍然有效的墙壁之间。我们认为基于二氧化硅的墙壁与调谐表面部分电荷，扩大从疏水性到亲水性。我们发现CT有效（即，它成功地预测了WCB几何形状和在壁上引起的力，对于所有考虑的表面，壁间距h >= h（0）= 3.0 nm。在这些分离处，CT保持不包括任何线张力，并且结果相对于用于从MD模拟获得WCB轮廓的方法是稳健的。对于所考虑的所有表面，约为2.0 nm = 2.5 nm。我们的结果解释的WCB内的水分子的重排，并表明，CT打破在h < h（0），因为它的假设，即WCB是一个bulklike水体积的固-液和液-气界面，不成立。
We perform molecular dynamics (MD) simulations of nanoscale water capillary bridges (WCBs) expanding between two parallel walls and determine the smallest separation between the walls above which the capillarity theory (CT) remains valid. We consider silica-based walls with tuned surface partial charges that expand from hydrophobic to hydrophilic. We find that the CT is valid (i.e., it predicts successfully the WCB geometry and forces induced on the walls) for, approximately, wall separations h >= h(0) = 3.0 nm for all surfaces considered. At these separations, the CT holds without including any line tension and the results are robust relative to the method employed to obtain the WCB profile from MD simulations. At approximately 2.0 nm = 2.5 nm for all surfaces considered. Our results are interpreted in terms of the rearrangement of water molecules within the WCBs and show that the CT breaks down at h < h(0) because its assumptions, that the WCB is a bulklike water volume confined by solid-liquid and liquid-vapor interfaces, do not hold.