Novel Grafting onto Silica via Aldehyde Functionality

Silica-bound aldehyde functional silane was used as a versatile bridge to attach porphyrin to the surface of silica and as a surface-bound free radical initiator to yield PMMA brushes. The aldehyde functionality is obtained by a simple ozonolysis of the surface-bound allylsilane, whereby the double bonds are oxidized in high yield to the desired aldehyde. Mono-amino porphyrin was attached to the silica surface under mild conditions via Schiff-base linkages, whilst anchored PMMA was obtained by free radical initiation using an aldehyde/redox free radical polymerization. FTIR and TGA data were used to determine and characterize the attachment to the silica surface.