title: Ultrathin organically modified silica layer coated carbon nanotubes: fabrication, characterization and electrical insulating properties.
abstract: This paper describes the use of organically modified silica (ormosil) for the ultrathin nanoprecise coating of individual multiwall carbon nanotubes using a soft-chemistry approach. Hybrid organic/inorganic ormosil nanocoated carbon nanotubes were successfully prepared by in-situ deposition of 3-aminopropyltrimethoxysilane or N-methylaminopropyltrimethoxysilane in an aqueous suspension by means of their electrostatic interactions with carboxylic group functionalized multiwall carbon nanotubes. The coating layer was found to have a uniform thickness of about 3 nm. The products were characterized by high-angle annular dark field scanning transmission electron microscopy, high-resolution transmission electron microscopy (HR-TEM), TEM/energy-dispersive X-ray spectroscopy, TEM/electron energy loss spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and current-voltage measurements. The ormosil coatings demonstrated the favorable electrical insulating properties of individual multiwall carbon nanotubes. We also show that the resistance of the insulating thin layer can be tuned by altering the substituents of alkylmethoxysilanes.
authors.affiliation: Biomaterial Systems Group, Biomaterials Center, National Institute for Materials Science, Nanomaterials & Biomaterials Research Building, 1-1 Namiki, Tsukuba, Ibaraki, Japan. martin.pumera@gmail.com
authors.forename: Martin
authors.initials: M
authors.lastname: Pumera
authors.forename: Toshio
authors.initials: T
authors.lastname: Sasaki
authors.forename: Bretislav
authors.initials: B
authors.lastname: Smíd
mesh_terms: D000178:Acrylamides / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D011437:Propylamines / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry*; D046590:Spectroscopy, Electron Energy-Loss
chemical_list: D000178:Acrylamides; D037742:Nanotubes, Carbon; D011437:Propylamines; D012821:Silanes; D012833:Siloxanes; C503297:aminopropyltrimethoxysilane-methylenebisacrylamide; C510784:ormosil