Physics of Complex Fluids and MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Langmuir. 2010 Mar 2;26(5):3280-5. doi: 10.1021/la903051k.
We investigated the dynamics of nanometer thin water films at controlled ambient humidity adsorbed onto two atomically smooth mica sheets upon rapidly bringing the surfaces into contact. Using a surface forces apparatus (SFA) in imaging mode, we found that the water films break up into a distribution of drops with a typical thickness of a few nanometers and a characteristic lateral size and spacing of several micrometers. Whereas the characteristic length is found to be independent of the ambient humidity, the characteristic time of the breakup decreases from approximately 1 to 0.01 s with increasing humidity. The existence of characteristic length and time scales shows that this breakup is controlled by an instability rather than a conventional nucleation and growth mechanism for SFA experiments. These findings cannot be explained by a dispersion-driven instability mechanism. In contrast, a model involving the elastic energies for the deformation of both the mica sheets and the underlying glue layer correctly reproduces the scaling of the characteristic length and time with humidity.
我们研究了在控制环境湿度下，迅速将两个原子级光滑云母片表面接触时，吸附在其上的纳米级薄水膜的动力学。我们使用表面力仪（SFA）的成像模式，发现水膜会破裂成具有几纳米典型厚度和几微米特征横向尺寸和间距的液滴分布。虽然特征长度与环境湿度无关，但破裂的特征时间会随着湿度的增加而从大约 1 秒减少到 0.01 秒。特征长度和时间尺度的存在表明，这种破裂是由不稳定性控制的，而不是 SFA 实验中常规的成核和生长机制。这些发现不能用分散驱动的不稳定性机制来解释。相比之下，一个涉及云母片和底层胶层变形弹性能的模型，正确地再现了特征长度和时间随湿度的缩放关系。
