Fluoropolymer Membranes for Low Surface Tension Degassing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current fluoropolymer membranes have limitations in achieving low critical wetting surface tension (CWST) values and resistance to organic solvents and aggressive chemicals, necessitating improved properties for effective fluid filtration and surface modification.

Innovation Solution

Development of a fluoropolymer with polymerized monomeric units of the formula A-X-CH2-B, where A is C6F13-(CH2)2, X is O or S, and B is vinylphenyl, with a weight average molecular weight of at least 100 Kd and a glass transition temperature of at least 33 °C, which is used to create superhydrophobic and oleophobic membranes through a one-step coating process, suitable for filtering fluids and imparting low surface tension to materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fluoropolymer membranes are used, then they provide basic filtration capability, but they fail to achieve low enough CWST values and sufficient resistance to organic solvents and aggressive chemicals

Engineering Contradiction:

Improveresistance to organic solvents and aggressive chemicalsVSAvoidCWST value

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical structure of fluoropolymer monomers by introducing specific functional groups (perfluorohexylethylene, thiomethyl, oxymethyl, vinylphenyl) to change the surface energy parameters and achieve lower CWST values while maintaining chemical resistance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite membrane structures by coating fluoropolymer onto porous support membranes, combining the low surface energy properties of the fluoropolymer with the mechanical strength and porosity of the support structure

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If complex post-treatment processes are applied to achieve low surface tension, then CWST values improve, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvesurface tensionVSAvoidpost treatment requirements

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent incorporates low surface energy functional groups directly into the fluoropolymer chain structure during polymerization, so the membrane possesses low CWST properties inherently without requiring subsequent surface modification or post-treatment steps

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent eliminates the need for complex post-treatment processes by integrating the surface energy modification function directly into the polymer synthesis stage, simplifying the manufacturing workflow

Inventive Principle:

Principle #2Taking out (Extraction)

3Object-affected harmful factors

If high polymer concentrations are used in coating, then surface tension decreases, but porosity retention and manufacturing efficiency deteriorate

Engineering Contradiction:

Improvesurface tensionVSAvoidpolymer concentration

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent changes the molecular structure parameters of the fluoropolymer (introducing specific monomeric units with formulas A-X-CH2-B where A is C6F13-(CH2)2, X is O or S, and B is vinylphenyl) to achieve lower surface tension at lower polymer concentrations

Inventive Principle:

Principle #35Parameter changes

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 resulting membranes exhibit stable oleophobic properties with surface tensions as low as 0.015 N/m, retaining porosity and stability under vacuum and exposure to acids, bases, oxidizers, and heat, while being adaptable to various porous supports and thin films, enabling efficient fluid degassing and filtration with high water breakthrough pressure and airflow rates.

Implementation Method 1

The fluoropolymer is a superhydrophobic polymer and can be used to impart oleophobic properties, i.e., a CWST of as low as 0.015 N/m (15 dynes/cm), to material surfaces

Methodology Applied

Scientific EffectSurface tension reduction: Surface Tension

Implementation Method 2

The porous membranes are suitable for removing gaseous impurities present in fluids at a concentration below 1 ppb

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Implementation Method 3

Oleophobic membranes retain at least 80% of their porosity

Methodology Applied

Scientific EffectPorosity: Porosity

Implementation Method 4

The invention also provides a method of preparing a porous membrane comprising the copolymer disposed on a porous support

Methodology Applied

Scientific EffectCoating deposition: Deposition (physical)

Data Source

PatentEP3296011B1Membranes comprising fluoropolymers

Publication Date: 2023.06.07 PALL CORP

Figure 1A~2B

AI summary

Disclosed are fluoropolymers with low CWST values and porous membranes made from the fluoropolymers. The fluoropolymer is made up of polymerized monomeric units of the formula A-X-CH2-B, wherein A is C6F13-(CH2)2, X is O or S, and B is vinylphenyl, and the fluoropolymer has a weight average molecular weight (Mw) of at least 100 Kd and/or a glass transition temperature of at least 33 °C copolymer. The porous membranes are suitable for degassing a variety of fluids.