Department of Chemical Engineering, University of Bath, Bath, UK.
J Colloid Interface Sci. 2012 Oct 15;384(1):149-56. doi: 10.1016/j.jcis.2012.06.051. Epub 2012 Jun 28.
While the stability of liquid films on substrates is a classical topic of colloidal science, the availability of nanostructured materials, such as nanotubes, nanofibres and nanochannels, has raised the question of how the stability of liquid films and their wetting behaviour is affected by nanoscale confinement. This paper will present the conditions for the stability of liquid films on and inside cylindrical solid substrates with nanometre scale characteristic dimensions. It is shown that the stability is determined by an effective disjoining/conjoining pressure isotherm which differs from the corresponding disjoining/conjoining pressure isotherm of flat liquid films on flat solid substrates. From the former, the equilibrium contact angles of drops on an outer or inner surface of a cylindrical capillary have been calculated as a function of surface curvature, showing that the expressions for equilibrium contact angles vary for different geometries, in view of the difference in thickness of the film of uniform thickness with which the bulk liquid (drops or menisci) is at equilibrium. These calculations have been extended to the case of glass nanocapillaries and carbon nanotubes, finding good agreement with experimental results in the literature.
虽然基底上的液体薄膜稳定性是胶体科学的一个经典课题，但纳米结构材料（如纳米管、纳米纤维和纳米通道）的出现引发了一个问题，即液体薄膜的稳定性及其润湿行为如何受到纳米尺度限制的影响。本文将介绍具有纳米尺度特征尺寸的圆柱形固体基底上液体薄膜的稳定性条件。结果表明，稳定性由有效离并/聚合力等温线决定，该等温线与平坦固体基底上平坦液体薄膜的相应离并/聚合力等温线不同。从前者可以计算出作为表面曲率函数的圆柱形毛细管壁上液滴的平衡接触角，表明由于与平衡的整体液体（液滴或弯月面）的均匀厚度薄膜的厚度不同，平衡接触角的表达式对于不同的几何形状而变化。这些计算已扩展到玻璃纳米毛细管和碳纳米管的情况，与文献中的实验结果吻合良好。
