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Ultrathin Organically Modified Silica Layer Coated Carbon Nanotubes: Fabrication, Characterization and Electrical Insulating Properties
Author(s) -
Pumera Martin,
Sasaki Toshio,
Šmíd Břetislav
Publication year - 2009
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200900008
Subject(s) - carbon nanotube , materials science , scanning electron microscope , coating , x ray photoelectron spectroscopy , transmission electron microscopy , chemical engineering , layer (electronics) , ormosil , nanotechnology , composite material , sol gel , engineering
Nice coat! Organically modified silica (ormosil) is used for the ultrathin nanoprecise coating of individual multiwall carbon nanotubes using a soft‐chemistry approach. The coating layer has a uniform thickness of about 3 nm. The ormosil coating demonstrates the favorable electrical insulating properties of individual multiwall carbon nanotubes.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.