Perfluorinated Composite Membranes Without Cross-Linking or Pore Preservers
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Solution Overview
Problem
Current organic solvent nanofiltration (OSN) membranes require cross-linking and pore-preserving agents, which are costly and environmentally harmful, and are difficult to scale up due to harsh solvent requirements and chemical instability, leading to high waste and energy consumption.
Innovation Solution
A method of fabricating composite membranes by contacting a perfluorinated polymer solution with a polymer layer and drying it at low relative humidity to form a perfluorinated polymer layer without cross-linking or pore-preserving agents, utilizing the influence of water vapor to control membrane properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cross-linking modifications are applied to polymeric OSN membranes to improve chemical stability in harsh solvents, then the membrane robustness and chemical resistance are improved, but the fabrication complexity and cost increase due to additional chemical treatments and waste disposal requirements
Solution Approach 1:
The patent extracts and eliminates the cross-linking step from the membrane fabrication process. By using perfluorinated polymers that inherently provide chemical stability without requiring cross-linking agents, the invention removes the complex chemical modification step while maintaining the desired chemical resistance and robustness in harsh solvent environments
Solution Approach 2:
The invention replaces expensive and environmentally harmful cross-linking chemicals with a simpler fabrication approach using perfluorinated polymers. This eliminates the need for costly waste disposal systems and reduces environmental impact while maintaining membrane performance
2Stability of the object's composition
If pore preserving agents such as polyethylene glycol are used to maintain membrane pore structure, then the pore structure is maintained, but the membrane must be kept in a wet state to prevent cracks, adding operational complexity
Solution Approach 1:
The patent removes the pore preserving agent step from the fabrication process. By using perfluorinated polymers with inherent structural stability, the invention eliminates the need for additional pore-preserving chemicals and the subsequent requirement to maintain membranes in a wet state, simplifying both fabrication and operation
Solution Approach 2:
The perfluorinated polymer membrane structure is self-stabilizing and does not require external pore-preserving agents. The material inherently maintains its pore structure without needing to be kept in a wet state, making the membrane self-sufficient and easier to handle
3Reliability
If multiple chemicals are used for cross-linking and pore preserving during membrane fabrication, then the membrane achieves desired properties, but large scale fabrication becomes expensive due to extensive waste disposal requirements
Solution Approach 1:
The invention extracts and eliminates multiple chemical treatment steps (cross-linking agents and pore preserving agents) from the fabrication process. By using perfluorinated polymers that inherently provide both chemical stability and pore structure maintenance, the patent dramatically reduces chemical waste generation and associated disposal costs for large-scale fabrication
Solution Approach 2:
The patent changes the material parameter by selecting perfluorinated polymers with inherent stability properties, eliminating the need for additional chemical modifications. This material selection approach reduces waste generation while maintaining membrane performance
4Device complexity
If PEEK membranes are used to avoid cross-linking and pore preservation, then the fabrication process is simplified, but PEEK can only be dissolved in very harsh solvents such as methane sulfonic acid and sulfuric acid, making large scale fabrication difficult
Solution Approach 1:
The patent replaces PEEK, which requires harsh solvents for fabrication, with perfluorinated polymers that can be processed in milder conditions. This substitution maintains the simplified fabrication approach while improving scalability and reducing the need for specialized handling of harsh chemicals
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 method produces membranes with high permeance and rejection rates for organic solvents, reducing production costs and environmental impact while maintaining mechanical stability and chemical resistance.
Implementation Method 1
drying the perfluorinated polymer solution to form a perfluorinated polymer layer physisorbed on the surface of the polymer layer
Implementation Method 2
water (on the surface of the membrane or in the environment) can critically influence the formation of composite membranes. In particular, it was found that a minute amount of water (and/or water vapour) can greatly influence the properties of the resultant composite membrane
Data Source
AI summary
The present invention relates, in general terms, to a composite membrane for use in filtration. The present invention also relates to a method of fabricating the composite membrane, and a method of filtrating using the composite membrane as disclosed herein. The method of fabricating a composite membrane comprising contacting a perfluorinated polymer solution with a surface of a polymer layer and drying the perfluorinated polymer solution at a relative humidity of less than 20% to form a perfluorinated polymer layer physisorbed on the surface of the polymer layer.