Interfacial voids, separation

In the separation of an adhering system at or near an interface, in terms of a craze mechanism, there will be four differences from separation within a bulk polymer. One is, that interfacial voids (or proto-voids) may exist. These can act as cavitation nuclei and interfacial craze formation, starting from such nuclei, would be orders of magnitude more rapid than crazing by homogeneous nuclea-tion. Such cavitation could also be more rapid than the processes that occur in the Taylor instability mechanism, particularly if it should happen that the voids at the interface formed a two-dimensional continuum. Patches of low-energy matter in the solid surface can also be loci of void initiation, even if no voids are present before loading. 

A significant difference between the interfacial events occurring here and those in previous studies, is that the earlier work always involved macroscopic separation of surfaces. Here, the fiber and matrix remain in relatively intimate contact after debonding, which very likely influences the intensity and time dependence of the resulting emission. For example, we expect possible quenching mechanisms involving the nearby surfaces and gases in the narrow void created by the broken interface, which would tend to reduce the intensity and duration (decay) after a separation event. 

The interfacial processes that influence adhesion are examined. These are the microscopic processes (wetting, adsorption and charge transfer) and the macroscopic processes (elastic energy storage, the elimination of voids, and dissipation of energy during separation). 

The spherical microcapsules (colloids) are formed by interfacial organic synthesis in water, but the capsule diameter is often too high for coating use and filtration of the dispersion to separate large from small particles is required. However, not only mesh size (voids) of the filtration device but also interactions between filtration material and microcapsules can be of importance for an efficient filtration. 

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