Nanometer-sized pits

Hovel, H., Becker, Th., Bettac, A., Reihl, B., Tschudy, M., and Williams, E.J. (1997). Crystalline structure and orientation of gold clusters grown in preformed nanometer-sized pits, A/jp/. Sutf. Sci. 115, 124—127. 

Examples of different emulsification routes based on the PIT method and the corresponding droplet sizes obtained are shown in Fig. 12. In this example [7,115], the emulsification of a polar oil, cetyl isononanoate, was performed with a surfactant mixture consisting of a long-chain ethoxylated alcohol (Cis/igEz) and glyceryl monostearate (GMS) nonionic surfactants. It was shown that in order to obtain nanometer-size droplets in the system studied, either a liquid crystalline phase or a bicontinuous microemulsion should be formed during emulsification [7]. 

The penetration of mercury in MCM-41, a material with smooth cylindrical pores, takes place at the pressure indicated by the Washbum-Laplace model, indicating that this model is still valid at the scale of a few nanometers. When the pore surface is pitted with micropores or when the pores are interconnected, like in the case of SBA-15, the Washbum-Laplace model underevaluates the size of the pores, due to the excess energy needed for advancement of the meniscus beyond the surface defects. 

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