Abstract
The regularly ordered pore arrangement and the narrow pore size distribution of
mesoporous silica offer possibilities for several applications such as drug delivery and
controlled release. A successful implementation requires methods that allow the selective
functionalisation of external and internal surfaces. A convenient and scale-up friendly
procedure for synthesising high quality mesoporous silica MCM-41 at room temperature
was developed. Amino-functionalised samples were analysed using several methods to
understand the grafting behaviour of aminopropylalkoxysilanes. The distribution of amino
groups on mesoporous silica surfaces was evaluated by analysing textural properties and
amino group loadings, as well as by labelling the amino groups with fluorescein
isothiocyanate (FITC) for photoluminescence spectroscopy. A reliable method to determine
the amount of grafted amino groups over a wide range of loadings was developed. The
functionalisation of mesoporous silica by vapour phase deposition was studied as an
alternative to the common solvent based techniques. The accessibility of amino groups
anchored on selected mesoporous silicas was investigated by FITC coupling. Onedimensional
channel systems with small pores (3.1 nm and 3.9 nm) and large pores (7.6 nm)
as well as three-dimensional channel systems were compared to non-porous silica. Several
methods for the selective functionalisation of the external surface of mesoporous silica
were critically evaluated.
Ritter, H T K