Functionalization Effects of Single-Walled Carbon Nanotubes as Templates for the Synthesis of Silica Nanorods and Study of Growing Mechanism of Silica

Abstract

Silica nanorods were successfully prepared through a sol-gel process in the presence of carboxylic-functionalized single-walled carbon nanotubes (C-SWCNTs). The effect of chemical functionalization of single-walled carbon nanotubes (SWCNTs) on the growth of the silica layer was investigated using pristine SWCNTs (P-SWCNTs) and C-SWCNTS. The C-SWCNTs served as a unique template to fabricate silica hybrid composite materials. The crystalline formation and growing mechanism of the silica layer on C-SWCNTs were explained by the hydrolysis and chemical bonding between silica precursors and carboxylated SWCNTs. The C-SWCNTs, as templates, were successfully encapsulated using silica, and used templates were removed by oxidation at high temperature. Finally, silica nanorods/nanowires were synthesized in forms of mold, and this silica fabrication mechanism could be applied for large-scale production of silica nanomaterials and highly flexible nanocomposites. The sequence of a silica encapsulation process of C-SWCNTs and removed C-SWCNTs was characterized using SEM, TEM, EDX, FT-IR and Raman spectroscopy, XRD, and electrical analysis.

Preparation of SiO2–GO hybrid nanoparticles and the thermal properties of methylphenylsilicone resins/SiO2–GO nanocomposites

“…In addition, the typical carbonyl band at 1736 cm À1 decreases in intensity obviously. This suggests that C¼O band on the GO surface could be converted to SiÀ ÀOÀ ÀC band after the sol-gel process of TEOS [45], which agrees well with the XPS anlysis. Fig.…”

Surface Chemistry in the Process of Coating Mesoporous SiO2 onto Carbon Nanotubes Driven by the Formation of SiOC Bonds

“…This result is at variance with conclusions drawn from recent studies that carboxylic acids served as anchoring sites during the reaction between TEOS and oxidized CNTs. [61] As a result of the nanotubes having uncovered ends, there is the possibility of exploiting a selective functionalization at the end of the carbon nanotubes through specific reactions that make use of the carboxylic acids, such as esterification or amidation, which is suitable for producing multifunctional systems.…”

Commentary: Nanomanufacturing

“…The current CNT fabrication processes can produce nanotubes in lengths that could vary up to 300% of the expected mean length. 9 The process is found feasible for constrained features under 20 nm; as long as the CNTs length variation within the current capability is not an issue.…”