Molecular Dynamics of Dewetting of Ultra-Thin Water Films on a Solid Substrate
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摘要: 运用分子动力学模拟研究固体表面超薄水膜的失稳和破裂过程.结果表明薄膜中小扰动将失稳,并在初始阶段线性增长.但固体和液体的相互作用对扰动的初期增长影响较小.最小厚度的下降导致薄膜发生破裂.此后破裂边缘以一定的动态接触角后退.与宏观理论预测一致,边缘半径随时间的变化与时间平方根成正比.若固液相互作用较强,将引起破裂时间延迟,动态接触角减小,固体表面附近的液体密度增加.Abstract: Molecular dynamics simulation was applied to study the instability and rupture process of ultra thin water films on a solid substrate. Results show the small disturbance of the film will develop linearly due to the spinodal instability, whereas the interactions between solid and liquid have less in fluences on the initial growth. Then the rupture occurs and the rim recedes with a dynamic contact angle. The radius of the rim varies with time as the square root of the time, which is consistent with the macroscopic theory available. Stronger interaction between solid and liquid will postpone rupture time, decline the dynamic contact angle and raise the density of water near the interface between solid and liquid.
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Key words:
- dewetting /
- molecular dynamics simulation /
- ultra-thin liquid film
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