Block copolymer composition and anion exchange membranes made therefrom

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing anion exchange membranes (AEMs) face challenges with low hydroxide conductivity, insufficient long-term chemical and mechanical stabilities, and poor stability in basic environments, which limits their wider adoption in electrochemical devices.

Innovation Solution

A composition comprising a quaternized crosslinked epoxy functionalized partially hydrogenated styrenic block copolymer combined with a thermoplastic polymer, such as polyphenylene ether, to enhance stability, ion conductivity, and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If crosslinker is introduced within the membrane to improve mechanical stability, then mechanical strength is improved, but manufacturing complexity increases due to multiple synthetic steps

Engineering Contradiction:

Improvemechanical strengthVSAvoidsynthetic process complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The membrane is divided into distinct functional blocks: styrenic hard blocks provide mechanical strength and crosslinking sites, while diene soft blocks provide flexibility and processability. This segmentation allows each block to fulfill its specific function without requiring complex multi-step synthesis of the entire polymer chain.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The block copolymer is pre-synthesized with built-in crosslinking capability through the styrenic blocks before membrane formation. This preliminary preparation of the polymer structure with inherent crosslinking sites eliminates the need for subsequent complex crosslinking steps during membrane manufacturing.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If ion exchange capacity is increased to improve hydroxide conductivity, then ion conductivity is improved, but chemical stability deteriorates in basic environment

Engineering Contradiction:

Improvehydroxide conductivityVSAvoidchemical stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The membrane exhibits local quality differentiation where styrenic blocks provide chemical stability and alkali resistance in regions requiring durability, while diene blocks with functional groups provide high ion exchange capacity and hydroxide conductivity in regions requiring ionic transport. This spatial separation of functions resolves the contradiction between conductivity and stability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The membrane is constructed as a composite of chemically distinct blocks: aromatic styrenic blocks offering exceptional alkali stability and aliphatic diene blocks providing high ion exchange capacity. This composite block copolymer structure allows simultaneous achievement of chemical stability and high hydroxide conductivity that cannot be obtained with homogeneous polymers.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If functionalized SBCs are used to improve membrane processability, then processability is improved, but mechanical strength reduces due to water absorption

Engineering Contradiction:

Improvemembrane processabilityVSAvoidmechanical strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The block copolymer exhibits dynamic properties where the hydrophobic styrenic blocks resist water absorption and maintain mechanical strength, while the hydrophilic diene blocks enable good processability and ion conduction. This dynamic balance of hydrophobic and hydrophilic segments allows the membrane to maintain strength while being processable.

Inventive Principle:

Principle #15Dynamics

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 composition achieves improved stability, increased ion conductivity, and enhanced mechanical properties, including a Young's modulus of 40 to 300 MPa, elongation at break of 10 to 40%, and a reduction in OH ion conductivity of less than 45% after soaking in KOH solution.

Implementation Method 1

the relatively low hydroxide conductivity... have been major barriers for wider adoptions of AEM-based technologies

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

A film prepared from the composition after soaking in 1 molar KOH for 500 hours at 80° C.

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

quaternized crosslinked epoxy functionalized partially hydrogenated styrenic block copolymer

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentUS20250197627A1Block copolymer composition and anion exchange membranes made therefrom

Publication Date: 2025.06.19 NOTARK CORP

AI summary

The disclosure relates to a composition comprising a quaternized crosslinked epoxy functionalized partially hydrogenated styrenic block copolymer (QxE-pHSBC), and a thermoplastic polymer (TP). The TP is characterized as having a tensile strength of >30 MPa, flexural modulus of >1.8 GPa, and heat deflection temperature of ≥75° C. The styrenic block copolymer precursor for QxE-pHSBC can have any of a sequential diblock, triblock or coupled structure, which can be extended to a tetrablock, a pentablock or a monohydroxylated block copolymer, with at least one of the blocks functionalized (epoxidized) and crosslinked.