Multizone Microporous Membrane for High-Throughput Filtration
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Solution Overview
Problem
Existing filtration technologies face challenges in achieving high throughput performance without increasing manufacturing costs or compromising membrane integrity, particularly in multizone membranes with asymmetric structures.
Innovation Solution
A multizone, unsupported microporous filtration membrane with a specific three-zone structure, comprising a symmetric or asymmetric first and second zone, and an asymmetric third zone positioned between them, is fabricated through a triple slot casting process, ensuring integral zones and improved throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple layers of membranes are used to improve filter throughput, then throughput performance is improved, but manufacturing cost increases
Solution Approach 1:
The membrane is divided into multiple functional zones (retentive zone, pre-filtration zone, support zone) within a single layer structure, each zone performing specific filtration functions. This segmentation allows the membrane to achieve the throughput performance of multiple layers while maintaining a single-layer construction that reduces manufacturing complexity and cost
Solution Approach 2:
A single membrane layer integrates multiple functions that would traditionally require separate layers: particle retention, pre-filtration, and structural support. The multizone asymmetric membrane performs all these functions simultaneously, eliminating the need for multiple separate membrane layers and reducing overall manufacturing cost
2Productivity
If additional process steps are used to modify the membrane surface to improve throughput, then throughput performance is improved, but manufacturing cost increases
Solution Approach 1:
The desired asymmetric structure with optimized surface properties is created during the initial membrane formation process rather than through subsequent modification steps. The phase inversion process inherently produces the required surface morphology and pore structure, eliminating the need for separate ablation or solvation treatment steps
Solution Approach 2:
The membrane modification function is extracted from separate post-processing steps and integrated into the membrane formation process itself. The phase inversion mechanism directly creates the modified surface structure during casting, removing the need for additional modification processes
3Productivity
If particles or fibers are introduced and then removed to create channels for high throughput, then throughput is improved, but manufacturing complexity increases
Solution Approach 1:
Instead of introducing and removing particles to create channels, the invention directly controls the phase separation parameters during membrane formation to inherently create the desired channel structure. By adjusting composition, temperature, and phase inversion conditions, the membrane self-organizes into a structure with optimized flow channels without requiring particle templates
4Productivity
If asymmetric membrane structure with gradient pore size is used to improve flux, then throughput is improved, but manufacturing robustness decreases
Solution Approach 1:
The membrane features distinct zones with locally optimized properties: a retentive zone with smaller pores for particle capture, a pre-filtration zone with intermediate pores, and a support zone with larger pores for high flux. Each zone is independently optimized for its specific function while maintaining overall manufacturing robustness through a single-layer construction
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 achieves significantly higher throughput than existing membranes, with a breaking strain of at least 20% and bubble point of 15-50 psi, maintaining filtration properties even when pleated, and outperforming Millipore Express® products of similar pore size.
Implementation Method 1
simultaneously or sequentially casting the solutions as 3 separate zones onto a support to form a multizone liquid sheet, effecting a phase separation of the 3 separate zones of solutions
Data Source
AI summary
The present application relates to a multizone, unsupported, microporous, high throughput membrane. The membrane includes a first microporous zone, a second microporous zone, and a third microporous zone, where the third microporous zone is positioned between the first and second microporous zones, with the first, second, and third microporous zones being integral with one another. Further aspects of the present application include a process for making the membrane and a filtration cartridge with the membrane of the present application.