[Preparation of surface-modified carbon nanotubes/silica composite gel glass]

Owing to their unique structure and properties, carbon nanotubes (CNTs) have become the highlight of research since they were discovered. Part of the research interest lies in introducing them into solid state matrix to make them materialized. However, CNTs tend to aggregate in the matrix, which makes it difficult to make homogeneous composites. In order to solve this problem, we first modified the surface of CNTs by chemically bonding them to 3-aminopropyltrie-thoxysilane (NH2 (CH2)3Si(OC2H5)3, APTES) using three-step reactions, and then connected them to silica network by sol-gel technique. In the present paper, CNTs were first treated with HNO3 to get CNTs-COOH, which were then treated with SOCl2 to be transferred to CNTs-COCl, and finally CNTs-COCl reacted with APTES to get CNTs-APTES. After that, CNTs were introduced into silica net work through the individual hydrolysis of CNTs-APTES, tetrathyloxysilane (Si(OC2H5)4, TEOS) and 3-glycidoxy-propltrimethoxysilane (CH2OCHCH2O(CH2)3Si(OCH3)3, GPTMS) as sol-gel precursors, and the copolymerization of their hydrolysis products. FTIR and SEM were used to characterize the composition and microstructure of the obtained samples. (Owing to the connection of CNTs with silica network, little aggregation of CNTs was observed and high-quality CNTs/SiO2 composite gel glass was obtained. A model of CNTs/SiO2 network was also given.