Physics of Fluids and MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Chemphyschem. 2012 Jun 4;13(8):2179-87. doi: 10.1002/cphc.201100900. Epub 2012 Feb 29.
Surface and bulk nanobubbles are two types of nanoscopic gaseous domain that have recently been discovered in interfacial physics. Both are expected to be unstable to dissolution because of the high internal pressure driving diffusion and the surface tension which squeezes the gas out, but there is a rapidly growing body of experimental evidence that demonstrates both bubble types to be stable. However, the two types of bubbles also differ in many respects: surface nanobubble stability is most probably assisted by the nearby wall, which can repel the water (in the case of hydrophobicity), accept physisorbed gas molecules, and reduce the surface area through which outfluxing can occur; bulk nanobubbles, on the other hand, must stabilise themselves. This is perhaps through ionic shielding, perhaps through diffusive shielding, or perhaps through both. Herein, the features of both bubble types are described individually, their common and disparate features are discussed, and emerging applications are examined.
表面纳米气泡和体相纳米气泡是最近在界面物理中发现的两种纳米级气态区域。由于内部高压驱动扩散以及表面张力将气体挤出，这两种纳米气泡都预计是不稳定的，但越来越多的实验证据表明这两种气泡类型都是稳定的。然而，这两种气泡在许多方面也存在差异：表面纳米气泡的稳定性很可能是由附近的壁面辅助的，壁面可以排斥水（在疏水性的情况下），接受物理吸附的气体分子，并通过减少流出的表面积来降低表面张力；另一方面，体相纳米气泡必须稳定自身。这可能是通过离子屏蔽，也可能是通过扩散屏蔽，或者两者兼而有之。本文分别描述了这两种气泡类型的特征，讨论了它们的共同和不同特征，并研究了新兴的应用。
