Perfluorocarbon-Free Membrane with Reentrant Pores for Desalination
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Solution Overview
Problem
Membrane distillation technologies rely on expensive, non-biodegradable perfluorocarbon coatings that are vulnerable to mechanical damage and degradation, failing to achieve robust water-repelling functionality without them.
Innovation Solution
A perfluorocarbon-free membrane with non-perfluorocarbon material featuring reentrant and doubly reentrant pores, where the material extends over the inlet and outlet, creating a smaller cross-sectional area, allowing air entrapment and preventing water intrusion, thus mimicking hydrophobic behavior without a hydrophobic coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If perfluorocarbon coatings are used to achieve water-repelling functionality, then water repellency is improved, but cost increases, biodegradability decreases, and mechanical durability worsens
Solution Approach 1:
The patent employs porous materials with specifically engineered pore structures (reentrant and doubly reentrant geometries) to achieve water repellency without perfluorocarbon coatings. The porous structure itself, combined with surface roughness, creates the hydrophobic effect through air entrapment, eliminating the need for fragile perfluorocarbon coatings while maintaining mechanical durability.
Solution Approach 2:
The patent changes physical parameters such as pore size, pore geometry (reentrant and doubly reentrant configurations), and surface roughness to achieve water repellency. By optimizing these parameters, the membrane achieves superhydrophobicity through structural design rather than chemical coating, improving mechanical strength while maintaining water repellency.
2Reliability
If perfluorocarbon coatings are used to prevent water intrusion, then separation performance is improved, but cost increases and environmental friendliness worsens
Solution Approach 1:
The patent extracts and eliminates the perfluorocarbon coating component from the membrane system while retaining the essential water-repelling functionality. By taking out the harmful perfluorocarbon substance and replacing it with a perfluorocarbon-free porous structure, the patent achieves the same separation performance without environmental harm.
Solution Approach 2:
The patent uses porous materials with optimized pore structures to achieve water vapor permeability and liquid water rejection. The porous structure allows water vapor to pass through while the reentrant pore geometry and surface roughness prevent liquid water intrusion, maintaining separation performance without perfluorocarbon coatings.
3Ease of manufacture
If conventional smooth pore structures are used, then manufacturing is simpler, but water entrapment capability decreases and water intrusion occurs
Solution Approach 1:
The patent employs asymmetric pore structures with reentrant and doubly reentrant geometries that have narrower openings at one end and wider cavities at the other. This asymmetric design creates capillary pressure that stabilizes air entrapment while preventing liquid water intrusion. The asymmetric structure is achieved through controlled fabrication processes that maintain ease of manufacture.
Solution Approach 2:
The patent utilizes curved and rounded pore geometries with reentrant configurations that enhance air entrapment stability. The curved surfaces and rounded pore openings create favorable capillary pressure distributions that prevent liquid water intrusion while maintaining manufacturability through standard ceramic or polymer processing techniques.
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 membrane effectively separates water vapor from saline water, achieving near 100% salt rejection and maintaining air entrapment for extended periods, demonstrating robustness and efficiency in desalination processes without the need for perfluorocarbon coatings.
Implementation Method 1
A portion of the non-perfluorocarbon material extends over the inlet and outlet of each the plurality of pores so that a cross-sectional area of the inlets and outlets in a direction of the extension of the non-perfluorocarbon material is smaller than a cross-sectional area of the respective pore
Implementation Method 2
The perfluorocarbon-free membrane effectively separates water vapor from saline water, achieving near 100% salt rejection
Data Source
AI summary
A perfluorocarbon-free membrane composed of a non-perfluorocarbon material having a first side and a second side opposite of the first side. The perfluorocarbon-free membrane also includes a plurality of pores, each having an inlet and outlet and each passing through the non-perfluorocarbon material so that each pore provides fluidic communication between the first and second sides of the non-perfluorocarbon material. A portion of the non-perfluorocarbon material extends over the inlet and outlet of each the plurality of pores so that a cross-sectional area of the inlets and outlets in a direction of the extension of the non-perfluorocarbon material is smaller than a cross-sectional area of the respective pore in the direction of the extension of the non-perfluorocarbon material. The perfluorocarbon-free membrane does not include a hydrophobic perfluorocarbon coating.