Quantitative Control over Electrodeposition of Silica Films onto Single-Walled Carbon Nanotube Surfaces

Abstract

Control over the thickness of a silica coating on single-walled carbon nanotubes (SWNTs) is highly desirable for applications in optics and in biomedicine. Moreover, a silica coating on SWNTs would also aid in avoiding tube−tube contact and bundle formation as well as tube oxidation, a scenario conducive to the use of appropriately functionalized carbon nanotubes as individualized gate dielectric materials in field effect transistors. In this work, we have developed two feasible and reliable means with which to coat SWNTs with various reproducible thicknesses of silica using an electrochemical sol−gel process. In one procedure, a SWNT mat was used as a working electrode for the direct deposition of silica. In the second, nanotubes were dispersed in solution and silica was deposited onto these solubilized nanotubes in the presence of a platinum working electrode. Applying a negative potential results in the condensation of a silica film onto the SWNT surface. The thickness of the silica coating can be controllably altered by varying the potential of the working electrode as well as the concentration of the sol solution. These methodologies have the advantages of ease of use, environmental friendliness, and utilization of relatively mild reaction conditions.

A convenient route to disperse pristine carbon nanotubes in polystyrene with no damage of nanotube electronic structure

“…Raman spectroscopy can sensitively probe the structure and electrical properties of CNTs [10]. As shown in Figure 3 the defect or disorder of the graphitic structure, while G-band is assigned to the in-plane vibrations of the graphitic wall.…”

Electrochemical co-deposition of sol–gel/carbon nanotube composite thin films for antireflection and non-linear optics

“…A few studies were reported regarding the electrodeposition of sol-gel and CNTs 46,47 . Wong and his coworkers 46 developed two approaches for the deposition of silica onto SWCNT.…”

Preparation and characterisation of core–shell CNTs@MIPs nanocomposites and selective removal of estrone from water samples

“…In this study, we focused on the development of a new methodology for using CNTs as carriers in both organic and aqueous solvents. Coating CNTs with SiO 2 was investigated as a potential synthetic route because SiO 2 has well-known insulating properties and biocompatibility [24]. Furthermore, the fabrication of a CNT-SiO 2 core@shell structure could eliminate the undesirable attractive interactions between the nanotubes and improve interfacial bonding with the matrix [25][26][27].…”