Hydrophilizing PTFE Membranes via Plasma Preconditioning

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Solution Overview

Problem

Preparing porous PTFE membranes for filtering challenging fluids like hot sulfuric peroxide mixtures and metal-containing fluids is a time-consuming and labor-intensive process, especially when requiring high metal scavenging efficiency and low flow resistance.

Innovation Solution

Exposing PTFE membranes to an energy source such as gas plasma or broadband UV to precondition them, followed by a hydrophilic coating, which increases the critical wetting surface tension and enhances metal scavenging efficiency while maintaining low flow resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional methods are used to prepare porous PTFE membranes for filtering challenging fluids, then metal scavenging efficiency can be achieved, but the preparation process is time-consuming and labor-intensive

Engineering Contradiction:

Improvemetal scavenging efficiencyVSAvoidpreparation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The PTFE membrane is pre-treated with plasma or UV irradiation before hydrophilic coating to activate the surface and improve coating adhesion. This preliminary action reduces the overall preparation time by eliminating the need for extensive surface preparation steps later in the process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the surface energy parameters of the PTFE membrane through plasma treatment or UV irradiation, transforming the hydrophobic surface into a hydrophilic one. This parameter change enables faster coating application and reduces preparation time while maintaining metal scavenging efficiency

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If conventional hydrophilization methods are used on PTFE membranes, then hydrophilicity can be improved, but the process is labor-intensive and difficult to integrate into existing manufacturing

Engineering Contradiction:

ImprovehydrophilicityVSAvoidmanufacturing integration

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The invention replaces mechanical and chemical treatment methods with plasma treatment or UV irradiation, which are more easily automated and integrated into existing manufacturing lines. This substitution reduces labor intensity while improving hydrophilicity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

By using plasma treatment or UV irradiation to change the surface parameters of the PTFE membrane, the process becomes more controllable and easier to integrate into automated manufacturing systems, reducing the labor-intensive nature of conventional methods

Inventive Principle:

Principle #35Parameter changes

3Reliability

If PTFE membranes are treated to increase metal scavenging efficiency, then metal removal performance improves, but flow resistance may increase

Engineering Contradiction:

Improvemetal removal efficiencyVSAvoidflow resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The hydrophilic coating is applied specifically to the pore surfaces of the PTFE membrane rather than the entire membrane. This local treatment increases metal scavenging efficiency at the pore interfaces while maintaining the overall porosity and low flow resistance characteristics of the membrane

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention creates a composite structure by combining the PTFE base material with a hydrophilic coating layer. This composite structure provides both the metal scavenging efficiency of the hydrophilic coating and the low flow resistance of the PTFE substrate

Inventive Principle:

Principle #40Composite materials

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

This method significantly reduces preparation time by about 50%, allows for easier integration into existing manufacturing processes, and results in membranes with high metal removal efficiency and low flow resistance, suitable for a wide range of filtration applications including sterile and industrial uses.

Implementation Method 1

exposing a porous PTFE membrane to an energy source selected from gas plasma and broadband UV, and preconditioning the membrane

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

exposing a porous PTFE membrane to an energy source selected from gas plasma and broadband UV

Methodology Applied

Scientific EffectUV irradiation: Photopolymerisation

Implementation Method 3

treating the preconditioned membrane to provide a hydrophilic coating

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentEP3124101B1Hydrophilizing PTFE membranes

Publication Date: 2021.08.04 PALL CORP

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AI summary

Methods for hydrophilizing porous PTFE membranes, and hydrophilized membranes, are disclosed.