UV Treated Membrane Surface Pore Expansion
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Solution Overview
Problem
Nanoporous and microporous membranes with small pores on the outer surfaces suffer from low throughput during the solvent-induced phase separation process, making it difficult to manufacture larger pores while maintaining the micro or nano pore size in the supporting layer.
Innovation Solution
Exposing the outer surface of the membrane to high-energy UV flashlamp irradiation induces micro-melting of the surface layer, increasing pore size and forming a melt-fused skin layer, which enhances the membrane's throughput without affecting the supporting layer's pore size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pores in the outer surface layer are made larger to increase throughput, then the membrane's throughput capacity increases, but the supporting layer's pore size control becomes difficult
Solution Approach 1:
The membrane is divided into two distinct layers: an outer surface layer with larger pores for high throughput and an inner supporting layer with smaller pores for precise filtration. This segmentation allows each layer to be optimized independently, resolving the contradiction between throughput and pore size control.
Solution Approach 2:
Different regions of the membrane have different pore size characteristics - the outer surface layer has larger pores while the supporting layer maintains smaller pores. This local differentiation enables the membrane to simultaneously achieve high throughput at the surface and precise filtration control in the supporting layer.
2Productivity
If high energy UV flashlamp is used to increase pore size, then throughput increases, but macro-melting can occur that seals pores reducing throughput
Solution Approach 1:
The UV flashlamp treatment is applied with controlled energy levels that are sufficient to induce micro-melting and pore enlargement but deliberately kept below the threshold that would cause macro-melting and pore sealing. This partial action approach achieves the desired pore size increase while avoiding harmful excessive effects.
Solution Approach 2:
The UV treatment parameters (energy density, exposure time, wavelength) are precisely controlled and optimized to achieve micro-melting of the polymer matrix without reaching the temperature or energy levels that would cause macro-melting and pore closure. This parameter optimization resolves the contradiction between throughput enhancement and pore reliability.
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 process significantly increases the membrane's throughput capacity while maintaining the log reduction value, preventing macro-melting that would reduce the membrane's performance by ensuring controlled energy exposure to the surface layer.
Implementation Method 1
exposing the first outer surface to ultra-violet light whereby the pores in the first surface are increased in size after exposure to the ultra-violet light
Implementation Method 2
the energy output of the flashlamp must be great enough to induce micro-melting of the outer surface layer such that in the UV irradiated surface layer, the pores increase in size and a melt-fused skin layer is formed
Data Source
AI summary
A membrane having a first outer surface having a plurality of pores in a skin layer and the plurality of pores having a closed perimeter in the skin layer. The membrane having a second outer surface and a porous supporting layer connecting the first outer surface to the second outer surface. The first outer surface of the membrane is a melt-fused skin layer from exposure to ultra-violet light.