Sulfonated Chitosan Dispersions for Stable Carbon Nanotube Mixtures

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Solution Overview

Problem

Existing methods for preparing conductive carbon material dispersions are complex, require multiple steps and ingredients, and often result in unstable suspensions, which can affect the electrical properties and stability of carbon black and carbon nanotube dispersions.

Innovation Solution

A method involving the dissolution of sulfonated chitosan in an aqueous solvent to create a dispersion of conductive carbon materials, such as carbon black or carbon nanotubes, which simplifies the process, reduces the need for additional agents, and enhances stability by using sulfonated chitosan as a dispersing agent.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional dispersing agents and multiple processing steps are used, then dispersion stability can be improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvedispersion stabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates unnecessary processing steps and ingredients from conventional dispersion methods. By removing foaming agents, thickening agents, and multiple processing steps, the invention achieves stable carbon black dispersions with a simplified single-step process using only sulfonated chitosan as dispersing agent.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Sulfonated chitosan serves multiple functions simultaneously: it acts as a dispersing agent, stabilizer, and processing aid in a single component. This multi-functional approach replaces the need for multiple specialized agents (foaming agents, thickening agents, dispersing agents) used in conventional methods.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Quantity of substance

If multiple dispersing agents and processing steps are used, then dispersion concentration can be improved, but manufacturing cost increases

Engineering Contradiction:

Improvedispersion concentrationVSAvoidmanufacturing cost

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent merges the functions of multiple dispersing agents and processing steps into a single sulfonated chitosan dispersing agent. This consolidation achieves high dispersion concentration (up to 40 wt% carbon black) while reducing the number of ingredients and processing steps, thereby lowering manufacturing cost.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention changes the chemical parameters of the dispersing agent by using sulfonated chitosan with specific sulfonation degrees (30-80%). This parameter optimization enables high dispersion concentration to be achieved with a single agent at optimal concentrations (0.1-5 wt%), reducing the need for multiple agents and associated costs.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If conventional dispersing methods are used, then dispersion can be achieved, but shelf life and stability are reduced

Engineering Contradiction:

Improvedispersion efficiencyVSAvoidshelf life

Core Design Contradiction:

ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent applies preliminary action by pre-sulfonating the chitosan to create sulfonated chitosan with enhanced dispersing capabilities before use. This pre-modification of the dispersing agent ensures optimal performance from the start, achieving both high dispersion efficiency and long-term stability (shelf life exceeding 45 days) simultaneously.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention uses sulfonated chitosan as a composite dispersing agent that combines the properties of chitosan (biocompatibility, film-forming ability) with sulfonation groups (enhanced dispersing power, electrostatic stabilization). This composite material structure provides both efficient dispersion and long-term shelf life stability.

Inventive Principle:

Principle #40Composite materials

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 method achieves stable dispersions with higher concentration and longer shelf life, as evidenced by no settling for at least 45 days, and eliminates the need for foaming and thickening agents, thereby improving the manufacturing efficiency and maintaining the photoelectrical properties of the conductive materials.

Implementation Method 1

sulfonated chitosan is dissolved in an aqueous solvent to obtain a 0.1-3 wt % solution of sulfonated chitosan

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

a conductive carbon material is added into the sulfonated chitosan solution and then dispersed evenly therein to obtain the dispersion of the conductive carbon material

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentUS7686981B1Dispersions of conductive carbon materials and methods for preparing the same

Publication Date: 2010.03.30 TAIWAN TEXTILE RESEARCH INSTITUTE

AI summary

A method for preparing a dispersion of conductive carbon materials is provided. The method includes dissolving a sulfonated chitosan in an aqueous solution, wherein the amount of the sulfonated chitosan of the solution is about 0.1-3 wt %. Then, a conductive carbon material is added into the solution, and the conductive carbon material in the solution is dispersed across the solution. The conductive carbon material can be carbon black or carbon nanotube.