Transducers Science and Technology Group, MESA+ Institute for Nanotechnology and IMPACT Institute of Mechanics, Processes and Control, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Chem Soc Rev. 2010 Mar;39(3):1096-114. doi: 10.1039/b909101g. Epub 2010 Feb 2.
In this critical review we treat the phenomenon of capillarity in nanoscopic confinement, based on application of the Young-Laplace equation. In classical capillarity the curvature of the meniscus is determined by the confining geometry and the macroscopic contact angle. We show that in narrow confinement the influence of the disjoining pressure and the related wetting films have to be considered as they may significantly change the meniscus curvature. Nanochannel based static and dynamic capillarity experiments are reviewed. A typical effect of nanoscale confinement is the appearance of capillarity induced negative pressure. Special attention is paid to elasto-capillarity and electro-capillarity. The presence of electric fields leads to an extra stress term to be added in the Young-Laplace equation. A typical example is the formation of the Taylor cone, essential in the theory of electrospray. Measurements of the filling kinetics of nanochannels with water and aqueous salt solutions are discussed. These experiments can be used to characterize viscosity and apparent viscosity effects of water in nanoscopic confinement. In the final section we show four examples of appearances of capillarity in engineering and in nature (112 references).
在这篇评论中，我们基于杨-拉普拉斯方程的应用，研究了纳米受限空间中的毛细现象。在经典毛细现象中，弯月面的曲率由受限几何形状和宏观接触角决定。我们表明，在狭窄的受限空间中，必须考虑不混溶压力和相关的润湿膜的影响，因为它们可能显著改变弯月面曲率。我们回顾了基于纳米通道的静态和动态毛细作用实验。纳米尺度受限的一个典型影响是出现毛细诱导负压。特别关注弹性毛细作用和电动毛细作用。电场的存在导致在杨-拉普拉斯方程中添加额外的应力项。一个典型的例子是泰勒锥的形成，这在电喷雾理论中是必不可少的。讨论了纳米通道中用水和盐水溶液填充的动力学测量。这些实验可用于表征纳米受限空间中水中的粘度和表观粘度效应。在最后一节中，我们展示了毛细作用在工程和自然中的四个实例（112 个参考文献）。
