Porous Polymeric Membrane with Segmented Pore Density
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Solution Overview
Problem
Synthetic polymer membranes used for filtration lack sufficient strength and retention of undesirable materials while providing good throughput, and those for inkjet applications often suffer from smearing issues.
Innovation Solution
A porous polymeric membrane with a high pore density in its bulk and specific pore size configurations, including a microporous skin surface and a second porous surface, is developed, along with a method of casting a polymer solution and inducing thermal phase inversion to form a membrane with enhanced properties suitable for filtration and inkjet applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional synthetic polymer membranes are used for filtration, then throughput is provided, but strength and retention of undesirable materials are insufficient
Solution Approach 1:
The membrane is divided into distinct functional layers: a microporous skin layer for retention and a bulk support layer for strength and throughput. This segmentation allows each layer to optimize its specific function while working together as a unified filtration system.
Solution Approach 2:
Different regions of the membrane have different pore densities tailored to their specific functions. The skin layer has lower pore density (at least 20 pores/50,000 μm2) for retention, while the bulk has high pore density (at least 120 pores/mm2) for structural integrity and flow capacity.
2Strength
If membranes with higher pore density are used to improve strength, then structural integrity improves, but retention capability may deteriorate
Solution Approach 1:
The membrane structure separates retention function (skin layer with controlled pore density) from structural support function (bulk layer with high pore density), allowing both requirements to be satisfied simultaneously without compromise.
Solution Approach 2:
The membrane combines two distinct polymeric materials with complementary properties: one material forms the retention-oriented skin layer while another forms the strength-oriented bulk support layer, creating a composite structure that leverages the advantages of both materials.
3Productivity
If membranes are used for inkjet applications, then filtration is provided, but smearing occurs
Solution Approach 1:
The microporous skin layer provides localized retention functionality with controlled pore size and density that specifically addresses inkjet application requirements, preventing smearing while maintaining filtration efficiency through optimized local pore characteristics.
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 provides sufficient strength, minimal smearing, and effective retention of undesirable materials while maintaining good throughput, making it suitable for various applications including inkjet, diagnostic, and pharmaceutical industries.
Implementation Method 1
exposing the cast solution to a temperature of at least about 95° F. for at least about 40 seconds; inducing thermal phase inversion of the solution to form a pre-membrane
Data Source
AI summary
Porous membranes including a first microporous skin surface having a pore density of at least about 20 pores/50,000 μm2, and a second porous surface, and a bulk between the surfaces, wherein the bulk has a pore density of at least about 120 pores/mm2, as well as methods of using and methods of making the membranes are disclosed.