Crosslinked Anion Exchange Membrane Using Water-Based Process

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Solution Overview

Problem

Existing anion exchange membranes face challenges such as slow and costly scale-up, limited processability, use of hazardous organic solvents, mechanical weakness, and variable stability of custom cations, with limited understanding of solution properties affecting film thickness and conductivity.

Innovation Solution

A water-insoluble membrane is created using poly(acrylamide-co-diallyldimethylammonium chloride) crosslinked with a water-soluble crosslinker like glutaraldehyde, allowing for the production of large-scale, mechanically robust films with controlled ion exchange capacity and water uptake, using a water-based process that avoids organic solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If custom polymer synthesis is used to create anion exchange membranes, then the membranes can achieve desired ion exchange capacity and conductivity, but the scale-up process becomes extremely slow and costly

Engineering Contradiction:

Improveion exchange capacityVSAvoidscale-up speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent changes the fundamental parameters of the synthesis approach by using commercially available polymers instead of custom-synthesized polymers, and by using water-based crosslinking instead of organic solvent-based polymerization. This allows scale-up from gram to kilogram levels without the years-long development time previously required

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts the custom polymer synthesis step entirely from the process, relying instead on commercially available polymers that can be purchased in large quantities. This eliminates the bottleneck of custom synthesis and allows direct scaling to industrial production levels

Inventive Principle:

Principle #2Taking out (Extraction)

2Manufacturing precision

If solvent casting is used to produce anion exchange membranes, then films can be cast with controlled thickness, but the process is limited by solubility of copolymers and requires hazardous organic solvents

Engineering Contradiction:

Improvefilm thickness controlVSAvoidhazardous organic solvents

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the solvent parameter from organic solvents to water, eliminating the need for hazardous materials while maintaining the ability to control film thickness through the casting process. The water-based crosslinking system enables this solvent substitution

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the previously harmful organic solvents into benign water, eliminating safety and environmental concerns while maintaining processability. The water-based system allows for safer handling and eliminates the need for specialized solvent recovery infrastructure

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If crosslinking is used to improve mechanical stability of anion exchange membranes, then membrane durability increases, but the synthesis becomes more complex and requires additional reagents

Engineering Contradiction:

Improvemechanical stabilityVSAvoidsynthesis complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent performs crosslinking as a preliminary step before membrane formation, allowing the crosslinked network to be established in solution before casting. This simplifies the overall process by combining multiple steps into a sequential workflow rather than requiring complex simultaneous operations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses a universal crosslinking approach that works with commercially available polymers, making the process broadly applicable to different polymer types without requiring polymer-specific synthesis protocols. This reduces complexity by creating a generalizable method rather than custom procedures for each polymer

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Area of stationary object

If large area membranes are produced, then the membranes become suitable for practical fuel cell applications, but maintaining uniform thickness and properties across the large area becomes difficult

Engineering Contradiction:

Improvemembrane areaVSAvoidthickness uniformity

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent performs crosslinking in solution before casting the membrane, allowing the entire large-area membrane to be crosslinked uniformly in a single batch. This preliminary crosslinking ensures uniform properties across the entire membrane area, avoiding the difficulty of maintaining uniformity during subsequent processing steps

Inventive Principle:

Principle #10Preliminary action

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 solution enables the production of large, thin, and conductive anion exchange membranes with improved mechanical stability and controlled ion exchange capacity, suitable for fuel cells and other electrochemical devices, using industrially available materials and reducing production costs.

Implementation Method 1

a water insoluble membrane comprising a polymer composition comprising poly(acrylamide-co-diallyldimethylammonium chloride) (PAAcDADMAC) crosslinked with a water soluble crosslinker

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding