Droplet spreading on a surface exhibiting solid-liquid interfacial premelting
Droplet spreading on a surface exhibiting solid-liquid interfacial premelting
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液滴在表面上铺展，表现出固液界面预熔化
DOI：
10.1016/j.actamat.2017.10.018
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发表时间：
2018-01
期刊：
影响因子：
9.4
通讯作者：
Laird Brian B.
中科院分区：
文献类型：
--
作者：
Yang Yang;Laird Brian B.
采用分子动力学模拟方法研究了液态Pb液滴在Al（111）衬底上的铺展动力学和平衡形态。先前发现Al-Pb固-液界面[Phys. Rev. Lett，110，096102（2013）]在低于Al熔点的温度下表现出固-液界面预熔融。由于Al（111）自由表面不表现出预熔化，Pb液滴的扩散伴随着从多面到预熔化的Al衬底的同时表面过渡。在这里，我们研究如何耦合的液滴扩散的预熔影响的扩散动力学和比较结果的两个标准的限制机制的液滴扩散：hydrodynamicspreading，其中的扩散能量耗散为主的粘性松弛，andkinetic spreading，其中界面摩擦占主导地位。这两种机制预测不同的幂律依赖的液滴半径随时间的变化。对于存在预熔化的温度（在875 K和铝的熔点之间），在中间时间观察到动力学扩散。由于Pb液滴仅部分润湿表面，因此液滴半径在长时间内以指数方式松弛至平衡液滴形状。在625 K（低于Al（111）粗糙化温度）下对多面系统的铺展模拟表明，该系统与流体动力学铺展机制一致。然而，当我们在922.38 K下研究一个系统时，在该系统中，通过引入谐波约束来人为地抑制预熔化，以给出与Al（111）自由表面一致的表面振动，我们观察到动力学扩散机制-如在预熔化系统中一样。当预熔融被抑制时，观察到的平衡接触角显着大于当预熔融存在时，即使在相同的温度下。因此，预熔层的存在对Al（111）/Pb固液界面热力学有显著影响，但对铺展机制影响不大。我们还观察到，在预熔层的存在下的液滴接触线的结构被描述为两个接触角（而不是通常的一个），由于额外的预熔层的存在下，和类似的结构中看到的反应润湿系统。
We study, using molecular-dynamics (MD) simulation, the spreading kinetics and equilibrium shape of liquid Pb droplets on an Al (111) substrate. The Al-Pb solid-liquid interface was found previously [Phys. Rev. Lett,110, 096102 (2013)] to exhibit solid-liquid interfacial premelting at temperatures below the Al melting point. Because the Al(111) free surface does not exhibit premelting, the spreading of a Pb droplet is accompanied by a simultaneous surface transition from a faceted to a premelted Al substrate. Here, we examine how the coupling of the droplet spreading to the premelting affects the spreading kinetics and compare the results to two standard limiting mechanisms of droplet spreading: hydrodynamicspreading, in which the spreading energy dissipation is dominated by viscous relaxation, andkinetic spreading, where interfacial friction dominates. These two mechanisms predict different power-law dependency for the droplet radius versus time. For temperatures where premelting is present (between 875 K and the melting point of aluminum), kinetic spreading is observed at intermediate times. Because Pb droplets only partially wet the surface, the droplet radius at long times relaxes exponentially to the equilibrium droplet shape. Spreading simulations of a faceted system at 625 K [below the Al(111) roughening temperature] show that this system is consistent with a hydrodynamic spreading mechanism. However, when we examine a system at 922.38 K in which premelting is artificially suppressed by introducing harmonic constraints to give surface vibrations consistent with the Al(111) free surface, we observe a kinetic spreading mechanism - as in the premelted system. When premelting is suppressed, the equilibrium contact angle is observed to be significantly larger than when premelting is present even at the same temperatures. Thus, we conclude that the presence of the premelting layer has a significant effect on the thermodynamics Al(111)/Pb solid-liquid interface, but little effect on the mechanism of spreading. We also observe that the structure of the droplet contact line in the presence of the premelting layer is described by two contact angles (instead of the usual one) due to the presence of the additional premelting layer, and resembles structures seen in reactive wetting systems.
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DOI：
10.1103/physrevb.51.7157
发表时间：
1995-03
期刊：
Physical review. B, Condensed matter
影响因子：
--
作者：
Theis;Horn
通讯作者：
Theis;Horn
DOI：
10.1088/0953-8984/21/46/464131
发表时间：
2009-09
期刊：
Journal of Physics: Condensed Matter
影响因子：
--
作者：
S. Mechkov;A. Cazabat;G. Oshanin
通讯作者：
S. Mechkov;A. Cazabat;G. Oshanin
影响因子：
9.4
作者：
W. Villanueva;W. Boettinger;J. Warren;G. Amberg
通讯作者：
W. Villanueva;W. Boettinger;J. Warren;G. Amberg
影响因子：
8.6
作者：
E. Webb;G. Grest;D. Heine
通讯作者：
E. Webb;G. Grest;D. Heine
DOI：
--
发表时间：
2011
期刊：
--
影响因子：
--
作者：
A. M. Molenbroek;-J.;W. M. Frenken
通讯作者：
A. M. Molenbroek;-J.;W. M. Frenken