For Whom a Puddle Is the Sea? Adsorption of Organic Guests on Hydrated MCM-41 Silica
Thermal and hydration effects on the mobility of compact and branched organic molecules and a bulky pharmaceutical substance loaded in submonolayer amounts onto mesoporous silica have been elucidated using 1H and 31P solid-state NMR. In all cases, the ambient hydration has a stronger effect than an...
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Veröffentlicht in: | Langmuir 2020-09, Vol.36 (38), p.11383-11392 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Thermal and hydration effects on the mobility of compact and branched organic molecules and a bulky pharmaceutical substance loaded in submonolayer amounts onto mesoporous silica have been elucidated using 1H and 31P solid-state NMR. In all cases, the ambient hydration has a stronger effect than an increase in temperature to 370 K for water-free silica. The effect of hydration depends on the guest and ranges from complete solvation to a silica–water–guest sandwich structure to a silica–guest/silica–water pattern. The mobility of the guests under different conditions has been described. The specific structure of the MCM-41 surface allows one to study very slow surface diffusion, a diffusivity of about 10–15 –10–16 m2/s. The data reported are relevant to any nonfunctionalized silica, while the method used is applicable to any phosphor-containing guest on any host. |
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ISSN: | 0743-7463 1520-5827 |
DOI: | 10.1021/acs.langmuir.0c02327 |