Nano-porous Polymer Membranes via Metal Salt Template

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Solution Overview

Problem

Current manufacturing processes for nano-porous polymer membranes are difficult to control, limited in applicability, and unsuitable for industrial-scale production due to specific material requirements and long production times, with restricted pore size variability.

Innovation Solution

A method involving a dispersion of polymers, metal salt nanoparticles, and diluents is used, where the dispersion is coated onto a substrate, dried, and then the metal salt is dissolved to create a nano-porous polymer membrane, allowing for continuous production and adjustable pore size and porosity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If phase separation process is used to manufacture porous polymer membranes, then porous structure is obtained, but the process is difficult to control and has limited applicability

Engineering Contradiction:
Improvepore structure controlVSAvoidprocess controllability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent uses metal salt nanoparticles as an intermediary template in the polymer matrix. These nanoparticles serve as a mediating structure that defines pore spaces when removed, providing precise control over pore size and distribution without requiring complex phase separation control. The nanoparticle template acts as a bridge between the polymer matrix and the desired pore structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent controls pore size by varying the size of metal salt nanoparticles used as templates. By changing this critical parameter (nanoparticle size), precise control over the final pore structure is achieved. This approach transforms the control problem from managing complex phase separation dynamics to simply selecting nanoparticles of the desired size.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If template based process with silica template is used, then shaped polymeric articles with pores in the range of 15-35 nm are obtained, but the process is not suitable for membrane production and has long production times

Engineering Contradiction:
Improvepore size controlVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent employs metal salt nanoparticles as disposable templates that are easily removed by dissolution. Unlike reusable silica templates requiring sintering and complex handling, these nanoparticle templates are inexpensive, readily dissolved in water to create pores, and enable continuous processing. This disposable approach dramatically speeds up production while maintaining precise pore size control.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Manufacturing precision

If magnetic field assisted phase separation is used, then porous membrane is created, but specific equipment is required and applicability is limited to specific material combinations

Engineering Contradiction:
Improveporous structure formationVSAvoidequipment requirements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts the magnetic field requirement from the process by using a different mechanism: metal salt nanoparticles as physical templates. Instead of using magnetic fields to induce phase separation, the method simply incorporates nanoparticles into the polymer matrix and removes them by dissolution. This extraction of the complex magnetic field equipment eliminates the limitation to specific material combinations and simplifies the overall process.

Inventive Principle:
Principle #2Taking out (Extraction)

4Manufacturing precision

If stretching process is used on specific polymer foils, then porous structure is obtained, but the process is only applicable to specific starting materials

Engineering Contradiction:
Improvepore structure creationVSAvoidmaterial compatibility
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal method applicable to any polymer that can form a matrix with metal salt nanoparticles. The nanoparticle template approach works with thermoplastics, thermosets, and various polymer compositions, unlike stretching which is limited to specific elastomers and foils. This universal applicability is achieved because the nanoparticle template method does not rely on material-specific mechanical properties.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 process results in versatile, reliable, and cost-effective production of large-area nano-porous polymer membranes with controlled porosity and pore size, suitable for advanced applications like breathable textiles and filters.

Implementation Method 1

removing said one or more metal salt particles by a dissolution step

Methodology Applied
Scientific EffectDissolution:

Implementation Method 2

coating a substrate with said dispersion

Methodology Applied
Scientific EffectCoating/Deposition: Deposition (physical)

Implementation Method 3

subjecting the obtained material to a drying step

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2665767B1Porous polymer membranes
Publication Date: 2016.02.24 ETH ZURICH
  • EP2665767B1 patent drawingFigure 1(a)~1(f)

AI summary

The invention relates to manufacturing processes for nano- porous polymer membranes as defined in the specification; to intermediates suitable to obtain such membranes; to polymer membranes as defined herein; to shaped articles containing such membranes; to the use of such membranes, shaped articles and intermediates.