Alterations of fluid phase transitions in porous materials are conventionally employed
for the characterization of mesoporous solids. In the first approximation, this may be based on the
application of the Kelvin equation for gas–liquid and the Gibbs–Thomson equation for solid–liquid
phase equilibria for obtaining pore size distributions. Herein, we provide a comparative analysis
of different phase coexistences measured in mesoporous silica solids with different pore sizes and
morphology. Instead of comparing the resulting pore size distributions, we rather compare the
transitions directly by using a common coordinate for varying the experiment’s thermodynamic
parameters based on the two equations mentioned. Both phase transitions in these coordinates
produce comparable results for mesoporous solids of relatively large pore sizes. In contrast, marked
differences are found for materials with smaller pore sizes. This illuminates the fact that, with
reducing confinement sizes, thermodynamic fluctuations become increasingly important and different
for different equilibria considered. In addition, we show that in the coordinate used for analysis,
mercury intrusion matches perfectly with desorption and freezing transitions.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:85945 |
| Date | 12 June 2023 |
| Creators | Enninful, Henry R.N.B., Enke, Dirk, Valiullin, Rustem |
| Publisher | MDPI |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 2350 |
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