Cation Exchange Membrane Composition for Low Resistance and Brittleness

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing cation exchange membranes (CEMs) are prone to instability, phase separation, and inhomogeneities, leading to high electrical resistance and decreased permselectivity, making them expensive and brittle.

Innovation Solution

A cation exchange membrane is obtained by curing a composition comprising a first crosslinking agent with an anionic group and polymerizable groups, a second crosslinking agent with at least 5 vinyl groups and no ionic groups, and a third crosslinking agent with 2 to 4 polymerizable groups and no ionic groups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If standard curable compositions are used to prepare CEMs, then the membranes can be formed, but they exhibit instability and phase separation leading to inhomogeneities

Engineering Contradiction:

Improvecomposition stabilityVSAvoidmembrane homogeneity

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent uses a composite crosslinking system combining three different crosslinking agents with specific functional groups. This composite approach creates a multi-functional network that simultaneously provides stability, prevents phase separation, and ensures homogeneous membrane structure through synergistic interactions between the different crosslinking mechanisms.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent specifies precise parameter ranges for each crosslinking agent including the number of polymerisable groups (2-4 for third agent), vinyl group count (≥5 for second agent), and functional group types. These parameter controls ensure optimal crosslinking density and distribution, preventing phase separation while maintaining composition stability during curing.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional CEMs are used, then ion transport function is provided, but electrical resistance is unexpectedly high

Engineering Contradiction:

Improveion transport functionVSAvoidelectrical resistance

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent creates local regions with optimized crosslinking density by using three different crosslinking agents with varying reactivities and functionalities. This local quality variation ensures adequate ion transport channels are maintained while providing sufficient mechanical strength, resulting in lower electrical resistance without compromising ion transport reliability.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If conventional CEMs are used, then membrane formation is achieved, but permselectivity is decreased

Engineering Contradiction:

Improvemembrane formationVSAvoidpermselectivity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent segments the crosslinking function into three distinct agents, each contributing specific properties: the first agent provides foundational crosslinking with anionic groups, the second agent (≥5 vinyl groups) enhances network density, and the third agent (2-4 polymerisable groups) fine-tunes the structure. This segmentation enables precise control over membrane morphology to achieve high permselectivity.

Inventive Principle:

Principle #1Segmentation

4Productivity

If standard CEM preparation methods are used, then membranes are produced, but they are brittle with low E Modulus

Engineering Contradiction:

Improvemembrane productionVSAvoidmechanical strength

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The three-crosslinking agent system serves multiple functions simultaneously: the first agent provides structural framework with anionic groups for ion exchange, the second agent creates dense crosslinking network for mechanical strength, and the third agent optimizes network uniformity. This multi-functionality eliminates brittleness while maintaining production efficiency.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 resulting membrane exhibits improved stability, reduced electrical resistance, enhanced permselectivity, and increased mechanical strength, making it more cost-effective and less brittle.

Implementation Method 1

comprising copolymerisable components, at least one of which contains an anionic group

Methodology Applied

Scientific EffectPolymerisation: Photopolymerisation

Implementation Method 2

CEMs comprise negatively charged groups that allow the passage of cations but reject anions

Methodology Applied

Scientific EffectIon exchange: Ion Exchange

Data Source

PatentUS20250144613A1Membranes

Publication Date: 2025.05.08 FUJIFILM MANUFACTURING EUROPE BV

AI summary

Compositions and cation exchange membranes having low brittleness, low ER, good pH stability and good PS obtainable by curing a composition comprising: (a) a first crosslinking agent comprising an anionic group and at least two polymerisable groups; (b) a second crosslinking agent comprising at least 5 vinyl groups and being free from ionic groups; and (c) a third crosslinking agent comprising 2, 3 or 4 polymerisable groups and being free from ionic groups.