Polymeric Droplets on Soft Surfaces: From Neumann's Triangle to Young's Law
Polymeric Droplets on Soft Surfaces: From Neumann's Triangle to Young's Law
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DOI：
10.1021/ma501672p
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发表时间：
2015-01-27
期刊：
影响因子：
5.5
通讯作者：
Dobrynin, Andrey V.
中科院分区：
文献类型：
--
作者：
Cao, Zhen;Dobrynin, Andrey V.
采用分子动力学模拟和理论计算相结合的方法研究了聚合物液滴在凝胶状表面上的形状变形。分子动力学模拟的结果的基础上，我们已经开发了一个理论模型的弹性表面上的液滴形状变形，考虑到表面和弹性能量的贡献。在该模型框架下对模拟结果的分析表明，平衡液滴形状受无量纲参数γ（SL）/G（S）a控制，其中γ（SL）是基底/液体界面的表面张力，G（S）是基底的剪切模量，a是聚合物液滴的接触半径。该参数描述了用于液体基底上的液滴的Neumanns三角形条件与用于刚性基底上的液滴的Youngs定律之间的交叉。在弹性毛细管长度远大于接触半径γ（SL）/G（S）>> a的极限下，我们恢复了液滴在液体基底上漂浮的Neumanns三角形条件。然而，在相反的极限下，gamma（SL）/G（S）
Shape deformation of polymeric droplets on gel-like surfaces is studied by using a combination of the molecular dynamics simulations and theoretical calculations. On the basis of the results of molecular dynamics simulations, we have developed a theoretical model of droplet shape deformation on elastic surfaces which takes into account surface and elastic energy contributions. Analysis of simulation results in the framework of this model shows that the equilibrium droplet shape is controlled by the dimensionless parameter gamma(SL)/G(S)a, where gamma(SL) is the surface tension of the substrate/liquid interface, G(S) is the shear modulus of the substrate, and a is the contact radius of polymeric droplet. This parameter describes crossover between Neumanns triangle conditions for liquid droplets on liquid substrates and Youngs law for droplets on rigid substrates. In the limit when the elastocapillary length is much larger than the contact radius, gamma(SL)/G(S) >> a, we recover the Neumanns triangle conditions for liquid droplets floating on liquid substrates. However, in the opposite limit, gamma(SL)/G(S)