Interaction of silane coupling agents with nano-silica probed by nano-IR*

The nanoparticle-polymer composite is a widely used electronic packaging material. To satisfy the miscibility of nanoparticles with polymer, the surface of nanoparticles needs to be modified. The particle surface modification has been widely studied. However, the interaction between the silane coupling agent (SCA) and the nanoparticle surface is not clear yet. This article aims to investigate the surface modification impact on the nano-SiO 2 particle surface and to clarify the interaction between chemical reagent and the particle surface. In this investigation nano-SiO 2 was characterized by thermal gravity analysis (TGA), Fourier transform infrared spectroscopy (FT - IR), and nano- IR. The FT - IR results showed that the specific peak of SCA appears in the synthesized nano-silica. The TGA experiments were carried out to test the weight loss of SCA modified nano-SiO 2 as well as the grafting efficiency of the surface modification. The FT-IR and TGA results confirmed the SCA chemical grafting onto the nanoparticle surfaces. The nano-IR test provided detailed information for nano-silica surface. It could not only show the topographical AFM images but also the corresponding nanoscale IR adsorption spectra of the nano-silica surface. The topographic image distinguished the nanoparticle from the substrate. The discrete domains spectra shows the existence of SCA on the silica surface, which indicated that the SCA was grafted onto the silica surface with chemical bonding.