Realistic Models of Hydroxylated Amorphous Silica Surfaces and MCM-41 Mesoporous Material Simulated by Large-scale Periodic B3LYP Calculations
✍ Scribed by P. Ugliengo; M. Sodupe; F. Musso; I. J. Bush; R. Orlando; R. Dovesi
- Book ID
- 102689996
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 502 KB
- Volume
- 20
- Category
- Article
- ISSN
- 0935-9648
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✦ Synopsis
Amorphous silica is a key inorganic material, with applications in many fields such as cromatography, microelectronics, and metal-supported catalysis. Moreover, amorphous silica is the basic constituent of mesoporous ordered materials such as the molecular sieve MCM-41. These materials present high surface areas and high pore volumes, rendering them very attractive supports for adsorption or immobilization of biologically relevant molecules in confined spaces. Indeed, due to their regular pore distribution, they are excellent candidates for controlled-drug-delivery systems, which was evidenced for the first time by the confinement of ibuprofen in MCM-41 matrices. One important factor that determines the adsorption and subsequent release of a drug is its interaction with the pore wall, which in this case contains large amounts of silanol groups. Thus, it is crucial to possess detailed structural information at a molecular level of the typology and distribution of the silanol groups at the wall interface. Unfortunately, due to the amorphous nature of the walls, long-range order among SiO 4 tetrahedra is lost, which means that no experimental