Aminopropylalkoxysilanes are frequently used for the functionalization of mesoporous silica. The analysis of amino group distributions on arrays of silica nanochannels by a combination of nitrogen sorption and confocal laser scanning microscopy provides valuable insight into the mechanisms underlying the interaction of these silanes with mesoporous silica surfaces. Tendencies towards external surface functionalization, non-uniform distribution in the pores, and hydrolysis of the silica framework are shown to depend to a large extent on the mobility of the aminopropylalkoxysilane molecules, which can be adjusted by the number and type of alkoxy groups.
Keywords: amines; confocal microscopy; distribution; mesoporous silica; nanochannels; nitrogen sorption; silanes.