Abstract: The exceptional physical properties of carbon nanotubes (CNTs) have the potential to transform materials science and various industrial applications. However, to exploit their unique properties in carbon-based electronics, CNTs regularly need to be chemically interfaced with metals. Although CNTs can be directly synthesized on metal substrates, this process typically requires temperatures above 350 °C, which is not compatible for many applications. Additionally, the CNTs employed here were highly densified, making them suitable as interconnecting materials for electronic applications. This paper reports a method for the chemical bonding of vertically aligned CNTs onto metal substrates that avoids the need for high temperatures and can be performed at temperatures as low as 80 °C. Open-ended CNTs were directly bonded onto Cu and Pt substrates that had been functionalized using diazonium radical reactive species, thus allowing bond formation with the open-ended CNTs. Careful control during grafting of the organic species onto the metal substrates resulted in functional group uniformity, as demonstrated by FT-IR analysis. Scanning electron microscopy images confirmed the formation of direct connections between the vertically aligned CNTs and the metal substrates. Furthermore, electrochemical characterization and application as a sensor revealed the nature of the bonding between the CNTs and the metal substrates.
Keywords:
carbon nanotubes ; metal–carbon interface ; bond formation
* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
In neat (no solvent); at 100℃; for 0.333333h;Microwave irradiation;
General procedure: a mixture of 1-methylimidazole (0.4105 g, 5 mmol), 1-bromobutane (0.6850 g, 5 mmol) was heated under microwave irradiation (or conventional heating) in a 10 mL pressurized glass tube fitted with a Teflon-coated septum at 80 C for 20 min. Then, LiOTf (0.78 g, 5 mmol) was added and the mixture was irradiated at 100 C for 20 min. After cooling, the mixture was diluted with MeCN (5 mL), and after removal of the precipitated salt LiBr, the filtrate was then filtered through Celite. The crude product was washed with Et2O and concentrated to give a colorless to pale yellow liquid (1.382 g, 96 % yield). The [BMIM]OTf was dried under reduced pressure. The purity and authenticity of the ionic liquids were confirmed by 1H and 13C NMR spectroscopy.
In acetone; acetonitrile; at 60℃; for 24h;
1-Butyl-3-methylimidazolium bromide was dissolved in acetone/acetonitrile (50:50) and an equimolar amount of LiTfO in acetone was added. The mixture was stirred for 1 day at 60 C and then filtered. The solvent was removed under reduced pressure and the crude product dissolved in CH2Cl2. Upon cooling to 5 C most of the Li halide precipitated and the precipitate was filtered off. The remaining solution was washed halide-free with deionized water (AgNO3 test) and filtered over a column filled with neutral Al2O3 and activated charcoal. The residual organic phase was freed from solvent under reduced pressure and dried under dynamic vacuum for 1-2 days at 80-90 C.
In neat (no solvent); at 120℃; for 0.5h;Microwave irradiation;
General procedure: a mixture of 1-methylimidazole (0.4105 g, 5 mmol), 1-bromobutane (0.6850 g, 5 mmol) was heated under microwave irradiation (or conventional heating) in a 10 mL pressurized glass tube fitted with a Teflon-coated septum at 80 C for 20 min. Then, LiOTf (0.78 g, 5 mmol) was added and the mixture was irradiated at 100 C for 20 min. After cooling, the mixture was diluted with MeCN (5 mL), and after removal of the precipitated salt LiBr, the filtrate was then filtered through Celite. The crude product was washed with Et2O and concentrated to give a colorless to pale yellow liquid (1.382 g, 96 % yield). The [BMIM]OTf was dried under reduced pressure. The purity and authenticity of the ionic liquids were confirmed by 1H and 13C NMR spectroscopy.