Pore filling schematic mechanisms

Figure 11, Schematic mechanisms of pore filling and pore blocking by liquid impregnation and by chemical vapor deposition (26).

Composite pore-filled membranes, which have a porous polymer structure filled with a polyelectrolyte as schematized in Figure 12.6, are receiving growing attention in the field of separation and purification and recently in fuel cell application (Yamaguchi et al. 2003). In these membranes, the porous polymer substrate acts as an inert host that constrains the swelling of an anchored polyelectrolyte and provides high mechanical strength for the obtained membranes. 

Figure 14.5 Schematic mechanisms of pore filling and pore blocking by liquid impregnation and by chemical vapor deposition. Source Reprinted with permission from Kollensky WV, Chem Phys Carbon, 9, 173, 1973. Copyright 1973, CRC Press, Boca Raton, Florida.

In membrane filtration, water-filled pores are frequently encountered and consequently the liquid-solid transition of water is often used for membrane pore size analysis. Other condensates can however also be used such as benzene, hexane, decane or potassium nitrate [68]. Due to the marked curvature of the solid-liquid interface within pores, a freezing (or melting) point depression of the water (or ice) occurs. Figure 4.9a illustrates schematically the freezing of a liquid (water) in a porous medium as a fimction of the pore size. Solidification within a capillary pore can occur either by a mechanism of nucleation or by a progressive penetration of the liquid-solid meniscus formed at the entrance of the pore (Figure 4.9b). 

Figure 5. Schematic of snap-off mechanism (gas is unshaded) showing (a) gas entry into liquid filled pore-throat (b) gas finger and wetting collar formation prior to breakup, and (c) liquid lens after snap-off. (Reproduced with permission from reference 60. Copyright 1989 Society of Petroleum Engineers.)...

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