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===Nanoporous membranes===
[[File:Microscopic model of a nanoporous membrane.jpg|thumb|upright=2|right| Microscopic model of a nanoporous membrane. The white open area represents the area the molecule can pass through and the dark blue areas represent the membrane walls. The membrane channels consists of cavities and windows. The energy of the molecules in the cavity is U<sub>c</sub> and the energy of a particle in the window is U<sub>w</sub>.]]
Nanoporous membranes are fundamentally different
If the assumption is made that the energy of a particle does not change when moving through this structure, only the entropy of the molecules changes based on the size of the openings. If we first consider changes the cavity geometry, the larger the cavity, the larger the entropy of the absorbed molecules which thus makes the Henry coefficient larger. For diffusion, an increase in entropy will lead to a decrease in free energy which in turn leads to a decrease in the diffusion coefficient. Conversely, changing the window geometry will primarily effect the diffusion of the molecules and not the Henry coefficient.
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