Semiconducting SWCNT Dispersion via Selective Copolymer Separation

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Solution Overview

Problem

Existing methods for producing semiconducting single-walled carbon nanotubes (SWCNTs) lack the ability to effectively separate and stabilize semiconducting SWCNTs from a mixture, limiting their application in devices such as transistors and sensors.

Innovation Solution

A method involving the use of a specific copolymer with structural units derived from certain monomers, which selectively disperses semiconducting SWCNTs while coagulating metallic SWCNTs, followed by centrifugation to enhance separability and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional separation methods are used, then metallic SWCNTs can be separated from semiconducting SWCNTs, but the separability and dispersion stability are insufficient

Engineering Contradiction:

ImproveseparabilityVSAvoiddispersion stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the chemical parameter of the dispersant by using a copolymer with specific structural units (including carboxylic acid groups and polyethyleneoxy groups) in controlled amounts. This parameter change enables selective interaction with semiconducting SWCNTs, achieving both high separability (90% or more) and dispersion stability simultaneously, resolving the technical contradiction between these two properties.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a copolymer dispersant that combines different structural units (carboxylic acid units, polyethyleneoxy units, and other units) into a single material. This composite structure allows the dispersant to simultaneously provide strong binding affinity for semiconducting SWCNTs and steric stabilization, achieving both high separability and dispersion stability that cannot be obtained with single-functional dispersants.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If existing dispersants are used, then SWCNTs can be dispersed, but the dispersion stability is insufficient for practical applications

Engineering Contradiction:

Improvedispersion stabilityVSAvoidseparability

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent optimizes the compositional parameters of the dispersant by controlling the content of specific structural units (carboxylic acid groups at 1-50 mol%, polyethyleneoxy groups at 1-50 mol%). This precise parameter control enables the dispersant to maintain both high separability and long-term dispersion stability, with semiconducting SWCNTs remaining stable for months without aggregation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The copolymer dispersant acts as an intermediary substance that mediates between semiconducting SWCNTs and the aqueous medium. The carboxylic acid groups bind to semiconducting SWCNTs while the polyethyleneoxy groups provide hydrophilicity and steric stabilization, enabling stable dispersion in water while maintaining high separability from metallic SWCNTs.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If simple separation operations are used, then the process is easy to operate, but the separability of semiconducting SWCNTs is insufficient

Engineering Contradiction:

Improvesimplicity of separation processVSAvoidseparability

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The copolymer dispersant enables the separation process to be self-service by automatically providing selective stabilization of semiconducting SWCNTs in the dispersion. When centrifugation is applied, the dispersant ensures that semiconducting SWCNTs remain in the supernatant while metallic SWCNTs precipitate, achieving high separability (90% or more) with a simple one-step centrifugation process without requiring complex multiple separation steps.

Inventive Principle:

Principle #25Self-service

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

Achieves high semiconducting SWCNT separability and dispersion stability, resulting in a supernatant liquid with increased semiconducting SWCNT content suitable for semiconductor applications.

Implementation Method 1

a specific copolymer as a separating agent... selectively disperses semiconducting SWCNTs while coagulating metallic SWCNTs

Methodology Applied

Scientific EffectSelective adsorption: Adsorption

Implementation Method 2

centrifuging the separation target SWCNT dispersion, and then collecting a supernatant liquid containing the semiconducting SWCNTs

Methodology Applied

Scientific EffectCentrifugal separation: Centrifugal Separation

Data Source

PatentUS12534371B2Method for producing semiconducting single-walled carbon nanotube dispersion

Publication Date: 2026.01.27 KAO CORP

AI summary

An aspect of the present disclosure relates to a method for producing a semiconducting single-walled carbon nanotube dispersion that includes a step of centrifuging a separation target SWCNT dispersion containing SWCNTs that include semiconducting SWCNTs and metallic SWCNTs, an aqueous medium, and a polymer, and then collecting a supernatant liquid containing the semiconducting SWCNTs. The polymer is a copolymer that includes a structural unit A derived from a monomer represented by Formula (1) below and a structural unit B derived from a monomer represented by Formula (3) below.CH2═CR0—COOM (1)CH2═CR5—COO-(EO)p—(PO)q—R6 (3)