Metal Coated Polymer Membrane Porosity Stability
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Solution Overview
Problem
Existing microporous membranes used for filtration and electrosorption face challenges in varying charge properties, complex production processes, and reduced porosity when coated with metals, which affects filtration efficiency and stability.
Innovation Solution
A method involving atomic layer deposition (ALD) to apply a thin metal or aluminum oxide coating on polymer membranes, maintaining porosity and filtration properties, and using magnetron sputtering for large-scale coating, ensuring the membrane remains inert and biocidal with reduced porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal coating is applied to a polymer membrane to enhance stability and biocidal properties, then reliability and inertness are improved, but porosity is reduced affecting filtration efficiency
Solution Approach 1:
The patent employs porous anodic aluminum oxide (AAO) as a coating material that inherently maintains a porous structure with controlled pore sizes (10-100 nm). This porous coating provides mechanical stability and biocidal properties through the aluminum oxide material while preserving filtration efficiency by maintaining porosity and allowing substance passage through the controlled porous network.
Solution Approach 2:
The metal coating is applied selectively to specific regions of the polymer membrane, particularly on the retentate side, rather than uniformly across the entire membrane. This localized coating approach provides stability and biocidal properties where most needed while minimizing impact on overall porosity and filtration performance in other regions.
2Strength
If a metal coating is applied to provide mechanical stability, then strength is improved, but the complexity of the production process increases
Solution Approach 1:
The patent replaces complex multi-step metal coating processes with electrostatic deposition methods that utilize electrical fields to deposit charged metal particles or aerosols onto the membrane surface. This substitution of mechanical coating processes with electrostatic fields simplifies the production process while achieving uniform metal coating for enhanced mechanical stability.
Solution Approach 2:
The patent controls coating parameters such as particle charge, aerosol concentration, deposition time, and electric field strength to optimize metal coating thickness and distribution. By precisely controlling these parameters, the process achieves desired mechanical stability without requiring complex multi-layer coatings or extensive post-processing steps.
3Manufacturing precision
If the pore size is reduced to improve retention of smaller substances, then filtration precision is improved, but the throughput decreases
Solution Approach 1:
The patent implements a multi-layer filtration structure with different pore sizes arranged in sequence. The polymer membrane provides initial filtration with larger pores for high throughput, while the porous metal coating layer with smaller pores (10-100 nm) provides secondary filtration for smaller substances. This segmented approach allows each layer to optimize for its specific function, maintaining overall high throughput while achieving high filtration precision.
Solution Approach 2:
The patent transitions from relying solely on the polymer membrane's pore size for filtration to adding a dimensional layer of porous metal coating with nanoscale pores. This additional dimensional layer provides a new filtration mechanism at the nanoscale that captures smaller substances without significantly impacting the macro-scale throughput determined by the underlying polymer membrane structure.
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 a stable, biocidal, and inert metal-coated polymer membrane with minimal reduction in porosity, enhancing filtration and electrosorption efficiency while maintaining high conductivity and throughput.
Implementation Method 1
A method involving atomic layer deposition (ALD) to apply a thin metal or aluminum oxide coating on polymer membranes
Implementation Method 2
using magnetron sputtering for large-scale coating
Implementation Method 3
This generally occurs mechanically via the pore size. All substances that are larger than the size of the pores are mechanically retained.
Implementation Method 4
there is still another mechanism that takes place to retain substances when passing through the membrane. This involves a non-defined adsorption by the materials of which the membrane itself is comprised
Implementation Method 5
Another form of adsorption is electrosorption. Electrosorption occurs by producing an electrically charged field on surfaces by applying a positive and negative voltage at two electrodes.
Data Source
AI summary
A metal coated polymer membrane, a method for the production thereof, an electrofiltration device, or an electrosorption device, and a method of electrofiltration and electrosorption using a metal coated polymer membrane. The polymer membrane is coated with metal using Atomic Layer Deposition (ALD).