Ionically Cross-Linked Polymeric Membranes for CO2 Separation
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Solution Overview
Problem
Current membrane technologies for CO2 separation face challenges in achieving good mechanical properties, high CO2 permeability and selectivity, ease of preparation, and low cost, particularly with poly(ionic liquid)s and poly(ethylene glycol) based membranes.
Innovation Solution
Development of cross-linked, ether-containing polymeric membranes with a flexible backbone, combining features of poly(ionic liquid)s and poly(trimethylene ether)glycol, using a one-step thermal polyaddition reaction to create ionically cross-linked triazolium-based polymers, which are solvent- and catalyst-free, and can be tailored for specific properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If poly(ethylene glycol) based membranes are used for CO2 separation, then CO2 selectivity is improved due to ether characteristics, but mechanical strength deteriorates due to high crystallinity
Solution Approach 1:
The patent combines PEG-based polymer chains with ionic liquid moieties to create a composite material that integrates the CO2-selective ether characteristics of PEG with the mechanical strength and flexibility of ionic liquids, resolving the contradiction between selectivity and mechanical strength
Solution Approach 2:
The patent modifies the physical and chemical parameters of the membrane by incorporating ionic liquid functional groups that alter the crystallinity and mechanical properties while maintaining CO2 affinity, transforming the material properties to achieve both high selectivity and strength
2Reliability
If poly(ionic liquid)s are used for CO2 separation, then CO2 selectivity is improved, but CO2 permeability deteriorates due to low permeabilities
Solution Approach 1:
The patent creates local regions with high CO2 affinity through ether oxygens while maintaining overall membrane porosity and flexibility, allowing CO2 to be selectively transported through specific pathways without compromising overall permeability
Solution Approach 2:
The patent incorporates flexible polymer backbones and mobile ionic liquid moieties that create dynamic, adaptable structures facilitating CO2 transport while maintaining selectivity, making the membrane more permeable than rigid PIL structures
3Reliability
If multistep synthetic methods are used to prepare triazolium-based polymers, then material properties are improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple synthetic steps into a single one-step thermal polyaddition reaction that simultaneously forms the triazole linkages and incorporates the ionic liquid functional groups, eliminating the need for separate quaternization steps and simplifying the overall synthesis process
Solution Approach 2:
The patent pre-organizes the molecular structure of monomers with terminal functional groups that enable direct polyaddition and simultaneous formation of the polymer backbone and ionic liquid moieties, allowing the complex structure to be built in a single reaction step rather than requiring sequential synthesis
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 membranes exhibit improved mechanical strength, CO2 transport properties, and selectivity, making them suitable for gas separation and potential applications in supercapacitors, batteries, and fuel cells, while being cost-effective and easy to fabricate.
Implementation Method 1
one-step thermal polyaddition of azide and propargyl-functionalized monomer
Implementation Method 2
The IL moieties in PIL membranes provide good CO2 selectivity
Implementation Method 3
Poly(ethylene glycol) (PEG) based polymeric membranes have been intensively investigated for CO2 separation. They are known to have high affinity towards CO2 due to the ether characteristics
Data Source
AI summary
Provided herein are compositions, CO2-permeable/selective membranes and related methods of making and using the membranes. Ionically cross-linked poly(ether)-based membranes were prepared for applications relating to CO2. These films were studied for their thermal curing behavior using DSC. The resulting free-standing membranes have Tgs near −64° C., TdS up to 230° C., and Young's modulus up to 4.2 MPa. These membranes showed CO2 permeabilities of 84-110 Barrer and CO2/N2 selectivity of 20-40.