Capillary force aggregation

Another instructive way to view capillary forces in MESA in three dimensions is to consider their analogy with the hydrophobic effect. The capillary forces in some of the systems we describe - especially those at the PFD/H20 interface - are essentially due to the hydrophobic effect, expressed at the meso-scale. Because the hydrophobic effect is strong on the molecular scale, capillary forces should be able to hold nanometer-sized objects in aggregates against thermal agitation. This view provides a link between molecular self-assembly and MESA using capillary forces. 

Colloidal zeolites have been used as building blocks to fabricate hierarchical porous materials. Infiltrating ethanol sol of zeolite nanoparticles into an ordered array of polystyrene spheres resulted in macroporous zeolites, which involves a self-assembly process. After ethanol evaporation, zeolite nanoparticles were aggregated by capillary forces. High concentration of external silanol groups favored the formation of hydrogen bonds between particles and eventually Si-O-Si bonds after calcination. The method has been further developed to produce transparent and self-standing zeolite membranes with controlled mesoporosity. Concurrently, the preformed zeolite-coated polystyrene spheres have been... 

An analysis has been presented [101] on the wetting of fine powders by aqueous solutions of anionic wetting agents in terms of adhesion tension, spreading coefficient and capillary forces involved in the displacement of air from externally wetted aggregates. This study revealed how the film preceding the bulk liquid can retard or markedly accelerate the submersion of powder in a liquid. 

Capillary forces at the surface of aggregates filled with liquid... 

In the case of interactions between inclusions in lipid bilayers (Figure 5.19) the elasticity of the bilayer interior must also be taken into account. The calculated energy of capillary interaction between integral membrane proteins turns out to be of the order of several Hence, this interaction can be a possible explanation of the observed aggregation of membrane proteins. The lateral capillary forces have been calculated also for the case of particles captured in a spherical (rather than planar) thin liquid film or vesicle. ... 

Organization of monodispersed spherical colloids into complex aggregates with well-controlled sizes, shapes, and internal structures by combining physical templating and attractive capillary forces... 

The basic model of a grease, then, is that of a self-supporting structure of interlocked fibers or aggregates of gellant, within which liquid is held by capillary forces. This model is consistent with the two characteristics most typical of grease resistance to change of... 

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