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US 12,428,299 B2Granted
Method for separating single-walled carbon nanotube mixture and single-walled carbon nanotube dispersion liquid
AssigneeNEC Corporation
InventorsKazuki Ihara, Hideaki Numata
Life of this patent
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Abstract
A method for separating a single-walled carbon nanotube mixture includes: preparing a dispersion liquid containing the single-walled carbon nanotube mixture and a surfactant; and separating the single-walled carbon nanotube mixture contained in the dispersion liquid, wherein in the separating the single-walled carbon nanotube mixture, a dispersion liquid in which a physical property of the dispersion liquid is within a prescribed range is used.
Claims22
A method for separating a single-walled carbon nanotube mixture, the method comprising:
- subjecting a single-walled carbon nanotube mixture that includes metallic single-walled carbon nanotubes and semiconducting single-walled carbon nanotubes to a cleaning treatment, the cleaning treatment including annealing the single-walled carbon nanotubes in a vacuum to remove functional groups present on the surfaces of the metallic and semiconducting single-walled carbon nanotubes,
- preparing a dispersion liquid by dispersing the single-walled carbon nanotube mixture that was subjected to the cleaning treatment in a solution containing a surfactant and a dispersion medium, the obtained dispersion liquid having an average zeta potential of −15 mV or higher and a pH of from 6.0 to 7.5;
- and
- separating the metallic single-walled carbon nanotubes from the semiconducting single-walled carbon nanotubes contained in the dispersion liquid by applying a direct current voltage in a vertical direction to the dispersion liquid,
- wherein the cleaning treatment of the single-walled carbon nanotube mixture is configured to adjust the average zeta potential of the dispersion to −15 mV or higher and to adjust the pH of the dispersion to from 6.0 to 7.5.
2 more elements
A single-walled carbon nanotube dispersion liquid comprising:
- a single-walled carbon nanotube mixture comprising metallic single-walled carbon nanotubes and semiconducting single-walled carbon nanotubes;
- and
- a surfactant,
- wherein the single-walled carbon nanotube mixture is subject to a cleaning treatment, the cleaning treatment including annealing the single-walled carbon nanotubes in a vacuum to remove functional groups present on the surfaces of the metallic and the semiconducting single-walled carbon nanotubes;
- the dispersion liquid is prepared by dispersing the single-walled carbon nanotube mixture that was subjected to the cleaning treatment in a solution containing a surfactant and a dispersion medium, the obtained dispersion liquid having an average zeta potential of
- −15 mV or higher and a pH of from 6.0 to 7.5;
- the metallic single-walled carbon nanotubes are separated from the semiconducting single-walled carbon nanotubes contained in the dispersion liquid by applying a direct current voltage in a vertical direction to the dispersion liquid;
- and
- the cleaning treatment of the single-walled carbon nanotube mixture is configured to adjust the average zeta potential of the dispersion to −15 mV or higher and to adjust the pH of the dispersion to from 6.0 to 7.5.
6 more elements
Dependencies are inferred from the claim text.