In many processes and applications, immobilization of active molecules through attachment to solid surfaces is a well-established procedure. As an aid to active molecules, silica micro- and nano-particles are attractive candidates due to a combination of favorable properties. The present study deals with the grafting of functional UV active molecules to silica surfaces using multivalent organosilicon spacers through hydrosilylation reactions. Different forms of dimethylsiloxysilane-based organosilicon precursors containing several SiH groups were used as spacers between the vinyl-modified silica surface and the UV-absorber benzotriazole (UVA). First, with the vinyltrimetoxsisilane coupling agent, the silica surface was modified. The UVA molecules were subsequently attached to the silica-vinyl through a two-step hydrosilylation reaction technique. Using various forms of multivalent organosilicon precursors that were used as spacers between the vinyl-modified silica surface and the UV-absorber, UV active molecules were successfully attached to the vinyl-modified silica surface. By FTIR, TGA and UV-Vis characterization, the successful grafting was verified. The multifunctional spacer MH30, which comprises approximately 75 SiH groups per molecule, showed a more than five-fold increase in UVA load compared to the four-functional spacer. In comparison, the linear spacer with the same functionality outperforms a branched, cumbersome six functional spacer. The UV behavior of functionalized silica was analyzed by UV-VIS spectroscopy, verifying that its UV absorbance properties were not altered by the immobilization of UVA on the silica surface.
Author (s) DetailsOlga Iliashevsky
Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel.
Elina Rubinov
Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel.
Yafa Yagen
Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel.
Moshe Gottlieb
Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 8410501, Israel.
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