Bundle-Type Carbon Nanotubes for Stable High-Concentration Dispersion
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Solution Overview
Problem
Carbon nanotubes face challenges with low solubility and dispersibility, leading to aggregation due to strong Van der Waals attraction, and methods to improve dispersibility often result in increased viscosity or decreased conductivity.
Innovation Solution
The development of bundle-type carbon nanotubes with specific density and production yield ratios, prepared through a method involving an organic acid, vanadium-based compound, cobalt-based compound, and thermal treatments, ensuring excellent dispersibility and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If carbon nanotubes are dispersed in a dispersion medium, then dispersibility is improved, but aggregation occurs due to strong Van der Waals attraction
Solution Approach 1:
The patent uses an ultrasonic wave as an intermediary force to overcome the Van der Waals attraction between carbon nanotubes. The ultrasonic energy acts as a mediator that temporarily separates the nanotubes during dispersion, allowing them to remain dispersed without direct chemical modification of the nanotubes themselves.
Solution Approach 2:
The patent applies ultrasonic vibration to the carbon nanotube dispersion system. The mechanical energy from ultrasonic waves creates cavitation and shear forces that break up aggregates and maintain nanotube separation in the dispersion medium, directly addressing the aggregation problem.
2Ease of operation
If ultrasonic treatment is applied to disperse carbon nanotubes, then dispersibility is improved, but the nanotubes begin to agglomerate when treatment is ended
Solution Approach 1:
The patent performs ultrasonic treatment as a preliminary action to achieve initial dispersion of carbon nanotubes. This preliminary mechanical energy input creates a dispersed state that serves as the starting point for subsequent stabilization, allowing the system to be processed in a dispersed state before final application.
Solution Approach 2:
The patent allows the carbon nanotube dispersion system to self-stabilize after ultrasonic treatment by utilizing the inherent properties of the dispersion medium and the dispersed nanotube structure. The system maintains its dispersed state through self-organization and equilibrium processes without requiring continuous external energy input.
3Ease of operation
If dispersing agents are used to stabilize carbon nanotubes, then dispersibility is improved, but viscosity increases when dispersed at high concentration
Solution Approach 1:
The patent employs a disposable ultrasonic treatment approach rather than relying on dispersing agents that require continuous presence in the system. The ultrasonic energy is applied temporarily to achieve dispersion, then removed, avoiding the ongoing viscosity increase associated with chemical dispersing agents in high-concentration dispersions.
4Reliability
If carbon nanotubes are dispersed at high concentration, then conductivity is improved, but handling becomes difficult due to increased viscosity
Solution Approach 1:
The patent replaces chemical dispersing agents with mechanical ultrasonic energy to achieve high-concentration dispersion. This substitution allows the system to reach high nanotube concentrations with improved conductivity while avoiding the viscosity problems associated with chemical additives, as the mechanical energy does not remain in the final product.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The bundle-type carbon nanotubes exhibit improved dispersibility and stability, maintaining conductivity at high concentrations, comparable to entangled-type nanotubes, with longer nanotube lengths and enhanced dispersibility in conductive material dispersions.
Implementation Method 1
preparing a mixture comprising an organic acid and a vanadium-based compound in a molar ratio of 1:(1 to 30)
Implementation Method 2
performing first thermal treatment of aluminum hydroxide to prepare a support
Implementation Method 3
reacting the supported catalyst with a carbon-based compound
Implementation Method 4
a method for dispersing carbon nanotubes in a dispersion medium through mechanical dispersion treatment such as ultrasonic treatment
Implementation Method 5
there is a problem of aggregation since carbon nanotubes are not stably dispersed in a dispersion medium due to strong Van der Waals attraction between them
Data Source
AI summary
The present invention relates to a bundle-type carbon nanotube which has a bulk density of 25 to 45 kg/m3, a ratio of the bulk density to a production yield of 1 to 3, and a ratio of a tap density to the bulk density of 1.3 to 2.0, and a method for preparing the same.