Surface modification of nanosilica with 3-mercaptopropyl trimethoxysilane: Experimental and theoretical study on the surface interaction

Surface modification of nanosilica with 3-mercaptopropyl trimethoxysilane (MPTMS) has been investigated. FTIR, TGA, CA, 29Si NMR and DFT method have been applied to study the interaction between nanosilica and MPTMS. The results show that the organic functional groups are successfully grafted onto the nanosilica surface and the grafting ratio firstly increases and then decreases with the increasing MPTMS. In addition, four different grafting modes between nanosilica surface and MPTMS have been studied by DFT method. It indicated that the favorable grafting structures are mono-, di-grafting mode when the MPTMS is lower and ladder-like grafting mode when the MPTMS is higher.