Hydrophobic Interactions and Dewetting between Plates with Hydrophobic and Hydrophilic Domains
Hydrophobic Interactions and Dewetting between Plates with Hydrophobic and Hydrophilic Domains
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DOI：
10.1021/jp8088758
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发表时间：
2009-04-02
影响因子：
3.7
通讯作者：
Berne, B. J.
中科院分区：
文献类型：
--
作者：
Hua, Lan;Zangi, Ronen;Berne, B. J.
我们通过分子动力学模拟研究了含疏水和亲水颗粒的平板之间的润湿/去湿转变和自由能对间距的依赖关系。我们发现，去湿对疏水和亲水结构域的分布非常敏感。特别是，我们发现，具有大范围疏水位置的平板会导致去湿转变和有吸引力的溶剂诱导的相互作用。另一方面，疏水和亲水颗粒在板上的均匀分布防止了去湿转变，并产生了排斥溶剂诱导的相互作用。我们还给出了一个类似于“Janus界面”的系统的结果，其中一个板由疏水颗粒组成，另一个板由亲水颗粒组成，表明板间隙保持湿润，直到小间距的空间约束将水分子排出。结果表明，非均质板接触角的卡西方程不能用来预测脱湿的临界距离。这些结果表明，具有强大的大尺度疏水性的纳米表面之间的疏水相互作用可以高度合作，因此他们反对在这些情况下不同表面域之间的疏水相互作用的可加性。这些发现与某些蛋白质之间的相互作用有关，在这些相互作用中，加性通常被认为是存在的。
We study by molecular dynamics simulations the wetting/dewetting transition and the dependence of the free energy on the distance between plates that contain both hydrophobic and hydrophilic particles. We show that dewetting is very sensitive to the distribution of hydrophobic and hydrophilic domains. In particular, we find that plates characterized by a large domain of hydrophobic sites induce a dewetting transition and an attractive solvent-induced interaction. On the other hand, a homogeneous distribution of the hydrophobic and hydrophilic particles on the plates prevents the dewetting transition and produces a repulsive solvent-induced interaction. We also present results for a system resembling a "Janus interface" in which one plate consists of hydrophobic particles and the other consists of hydrophilic particles showing that the interplate gap remains wet until steric constraints at small separations eject the water molecules. Our results indicate that the Cassie equation, for the contact angle of a heterogeneous plate, can not be used to predict the critical distance of dewetting. These results indicate that hydrophobic interactions between nanoscale surfaces with strong large length-scale hydrophobicity can be highly cooperative and thus they argue against additivity of the hydrophobic interactions between different surface domains in these cases. These findings are pertinent to certain protein-protein interactions where additivity is commonly assumed.