Composite Membrane Structure for High Permselectivity and Low Resistance
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Solution Overview
Problem
Existing ion exchange membranes lack improved properties such as high permselectivity, low electrical resistance, good mechanical strength, and stability at extreme pH conditions, while also being inefficient and costly to produce.
Innovation Solution
A composite membrane structure comprising multiple layers of porous supports and ionic polymers, with a third layer having a co-continuous network of oppositely charged ionic polymers, enhancing the contact area and adhesion between layers to prevent ion recombination and improve productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a porous support is used to provide mechanical strength, then mechanical strength is improved, but the membrane structure becomes more complex and production becomes more difficult
Solution Approach 1:
The patent employs composite materials by combining porous support layers with ion-exchange polymer layers to create a multi-layered membrane structure. The porous support provides mechanical strength while the polymer layers provide ion-exchange functionality, resolving the contradiction between mechanical strength and structural simplicity through material composition rather than structural complexity.
Solution Approach 2:
The patent utilizes porous support materials as the foundational layer, which provide mechanical strength and structural integrity. The porous structure allows for subsequent polymer infiltration and maintains permeability while providing the necessary mechanical framework, thus improving strength without excessive structural complexity.
2Reliability
If multiple layers with ionic polymers are used to improve permselectivity and prevent ion recombination, then permselectivity is improved, but manufacturing complexity and production cost increase
Solution Approach 1:
The patent divides the membrane into multiple functional layers: porous support layers and ion-exchange polymer layers. Each layer has a specific function (mechanical support vs. ion selectivity), allowing the system to achieve high permselectivity through functional segmentation rather than through complex interlayer interactions, thus improving reliability while managing manufacturing complexity.
Solution Approach 2:
The patent implements a nested structure where ion-exchange polymer layers are positioned between porous support layers, creating an alternating multi-layered configuration. This nesting arrangement allows each polymer layer to perform its ion-selective function independently while being mechanically supported by the porous layers, achieving high permselectivity without requiring complex integration of all layers.
3Productivity
If the third layer contains a co-continuous network of oppositely charged ionic polymers to increase contact area, then productivity is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies local quality by creating a co-continuous network of oppositely charged ionic polymers specifically in the third layer, while other layers maintain simpler structures. This localized complexity in the third layer maximizes water dissociation efficiency and ion transport productivity without requiring all layers to be equally complex, thus improving productivity while managing manufacturing ease through selective complexity placement.
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 composite membrane design increases the dissociation of water molecules into H+ and OH- ions, enhances mechanical strength, and prevents ion recombination, leading to improved efficiency and productivity with reduced swelling and electrical resistance.
Implementation Method 1
the third ionic polymer is obtainable by phase-separation of the third ionic polymer from a composition used to prepare the third ionic polymer
Implementation Method 2
the third layer c) is interposed between the first layer a) and the second layer b); wherein one of the third ionic polymer and the fourth ionic polymer is a cationic polymer and the other is an anionic polymer
Data Source
AI summary
A composite membrane comprising: a) a first layer comprising a first porous support and a first ionic polymer present in the pores of the first porous support; b) a second layer comprising a second porous support and a second ionic polymer present in the pores of the second porous support; c) a third layer comprising a third porous support, a third ionic polymer and a fourth ionic polymer, wherein the third ionic polymer is present in the pores of the third porous support; wherein: (i) one of the first ionic polymer and the second ionic polymer is a cationic polymer and the other is an anionic polymer; (ii) the third layer c) is interposed between the first layer a) and the second layer b); (iii) the third ionic polymer comprises a network of pores and the fourth ionic polymer is present within the pores of the third ionic polymer; and (iv) one of the third ionic polymer and the fourth ionic polymer is a cationic polymer and the other is an anionic polymer.