Ester-Functional Separation Membrane Resists Protein Deposition

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Solution Overview

Problem

Existing separation membranes face challenges in resisting the deposition of proteins and organic substances, leading to reduced performance and biological reactions, particularly in applications involving blood and water purification, where compatibility and resistance are crucial.

Innovation Solution

A separation membrane with a functional layer having localized ester groups, as determined by X-ray electron spectroscopy, is developed, using an ester group-containing polymer that inhibits protein deposition by maintaining a balance of hydrophilicity and hydrophobicity, thereby enhancing separation performance and compatibility with blood.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a separation membrane is coated with hydrophilic polymers such as polyvinylpyrrolidone to prevent protein deposition, then deposition resistance is improved, but the membrane requires large amounts of hydrophilic polymer in the stock solution and has limited compatibility options

Engineering Contradiction:
Improveprotein depositionVSAvoidmembrane preparation complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the chemical parameters of the polymer by introducing ester groups through copolymerization of vinyl acetate and vinylpyrrolidone. This creates a polymer with balanced hydrophilicity and hydrophobicity that achieves deposition resistance without requiring large amounts of pure hydrophilic polymer in the stock solution

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymer structure by copolymerizing vinyl acetate (hydrophobic) and vinylpyrrolidone (hydrophilic) units. This composite material combines the advantages of both polymer types, achieving deposition resistance while maintaining membrane performance and simplifying preparation

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If polyvinyl alcohol is coated on polysulfone-based separation membrane to form a coating layer, then coating formation is improved through hydrophobic interaction, but separation performance is significantly reduced and blood compatibility deteriorates due to complement activation

Engineering Contradiction:
Improvecoating layer formationVSAvoidblood compatibility
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a copolymer with specific regional characteristics - vinyl acetate units provide hydrophobic regions for strong coating formation on polysulfone, while vinylpyrrolidone units provide hydrophilic regions that prevent complement activation and maintain blood compatibility. This local differentiation of properties within the same polymer chain resolves the contradiction

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent modifies the chemical composition parameters of the coating polymer by controlling the copolymer ratio of vinyl acetate to vinylpyrrolidone. This parameter optimization allows sufficient coating formation while limiting complement activation, achieving both stable coating and blood compatibility

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If hydrophilic polymers such as polyvinylpyrrolidone or polyethylene glycol are used to coat material surfaces, then protein deposition is temporarily inhibited, but the inhibition is not sustained and long-term performance is reduced

Engineering Contradiction:
Improveprotein deposition inhibitionVSAvoiddeposition resistance duration
Core Design Contradiction:
Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The patent merges the functions of hydrophobic interaction (for strong adhesion and stable coating) and hydrophilic deposition resistance into a single copolymer structure. The vinyl acetate units provide hydrophobic anchoring to the membrane surface while vinylpyrrolidone units provide sustained hydrophilic protection, creating long-term deposition resistance

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent performs preliminary action by forming a stable, well-adhered coating layer through hydrophobic interactions of vinyl acetate units before the membrane contacts blood or proteins. This pre-formed stable coating provides a lasting hydrophilic barrier that maintains deposition resistance over extended periods

Inventive Principle:
Principle #10Preliminary action

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 effectively resists protein deposition and maintains high separation performance, making it suitable for applications requiring blood compatibility and resistance to organic substances, such as blood purification and water treatment.

Implementation Method 1

a coating layer can be efficiently formed on the membrane surface by hydrophobic interaction between polysulfone and vinyl acetate

Methodology Applied
Scientific EffectHydrophobic interaction: Van der Waals Force

Implementation Method 2

the ester group-containing polymer has both hydrophilic and hydrophobic properties in molecules

Methodology Applied
Scientific EffectHydrophobic effect: Hydrophobe

Data Source

PatentEP2286902B1Separation membrane and module using the separation membrane
Publication Date: 2020.02.19 TORAY INDUSTRIES INC
  • EP2286902B1 patent drawingFigure 1
  • EP2286902B1 patent drawingFigure 2
  • EP2286902B1 patent drawing

AI summary

Provided is a separation membrane module suffering from little sticking of organic matters, proteins, platelets and so on. A separation membrane which is a membrane comprising a polymer, characterized in that a functional layer is formed on the surface in one side of the membrane, the peak area percentage of carbon derived from ester group measured by the electron spectroscopy for chemical analysis (ESCA) on the surface of the preceding functional layer is 0.1% (by atomic number) or more but not more than 10 (% by atomic number), and the peak area percentage of carbon derived from ester group measured by the electron spectroscopy for chemical analysis (ESCA) on the surface opposite to the functional layer is not more than 10 (% by atomic number); and a separation membrane module provided with the same as a built-in membrane.