Ionic Liquid Grafted Polyethersulfone Membrane for Water Filtration

Solution Overview

Problem

Current PES ultrafiltration membranes suffer from strong hydrophobicity, leading to poor antifouling performance and low separation efficiency, which limits their application in water filtration systems.

Innovation Solution

The method involves grafting an ionic liquid (IL) onto polyethersulfone (PES) molecular chains using 60Co-γ radiation, followed by immersion-precipitation phase transformation and Soxhlet extraction to enrich the IL on the membrane surface, thereby enhancing hydrophilicity and antifouling properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If PES ultrafiltration membrane is used, then thermal stability and mechanical properties are improved, but hydrophilicity and antifouling performance deteriorate

Engineering Contradiction:

Improvemechanical propertiesVSAvoidhydrophobicity

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by modifying only the surface layer of the PES membrane with hydrophilic polymers and inorganic particles, while maintaining the bulk PES structure for mechanical strength. The surface modification layer thickness is controlled to be 1-10 μm, providing hydrophilicity where needed without compromising the underlying mechanical properties of the PES substrate.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite membrane structure by combining PES with hydrophilic polymers (such as PVP, PEG, or chitosan) and inorganic particles (such as TiO2, SiO2, or ZnO). This composite approach allows the membrane to simultaneously exhibit the mechanical strength of PES and the hydrophilic/antifouling properties of the added materials.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If surface modification by ultraviolet or ozone is applied, then hydrophilicity is improved, but pore size and distribution are altered

Engineering Contradiction:

ImprovehydrophilicityVSAvoidpore size and distribution

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies local quality by modifying only the surface layer of the PES membrane with hydrophilic polymers and inorganic particles, while maintaining the bulk PES structure for mechanical strength. The surface modification layer thickness is controlled to be 1-10 μm, providing hydrophilicity where needed without compromising the underlying mechanical properties of the PES substrate.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes parameters by controlling the concentration of hydrophilic polymers (0.1-10% w/w), inorganic particles (0.1-10% w/w), and modification temperature (20-100°C) to achieve desired hydrophilicity while maintaining stable pore structure. The pore size is maintained within 0.01-10 μm through optimized modification conditions.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If hydrophilic polymers such as PVP or PEG are mixed with PES, then hydrophilicity is temporarily enhanced, but permanent modification is not achieved

Engineering Contradiction:

ImprovehydrophilicityVSAvoidpermanent modification

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent creates a composite membrane structure by combining PES with hydrophilic polymers (such as PVP, PEG, or chitosan) and inorganic particles (such as TiO2, SiO2, or ZnO). This composite approach allows the membrane to simultaneously exhibit the mechanical strength of PES and the hydrophilic/antifouling properties of the added materials.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes parameters by controlling the concentration of hydrophilic polymers (0.1-10% w/w), inorganic particles (0.1-10% w/w), and modification temperature (20-100°C) to achieve desired hydrophilicity while maintaining stable pore structure. The pore size is maintained within 0.01-10 μm through optimized modification conditions.

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If chemical bulk modification of PES is applied, then molecular design flexibility is improved, but harsh reaction conditions and corrosive reagents are required

Engineering Contradiction:

Improvemolecular designVSAvoidreaction conditions

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by modifying only the surface layer of the PES membrane with hydrophilic polymers and inorganic particles, while maintaining the bulk PES structure for mechanical strength. The surface modification layer thickness is controlled to be 1-10 μm, providing hydrophilicity where needed without compromising the underlying mechanical properties of the PES substrate.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes parameters by controlling the concentration of hydrophilic polymers (0.1-10% w/w), inorganic particles (0.1-10% w/w), and modification temperature (20-100°C) to achieve desired hydrophilicity while maintaining stable pore structure. The pore size is maintained within 0.01-10 μm through optimized modification conditions.

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 modified PES membranes exhibit improved hydrophilicity, antifouling performance, and water flux, while maintaining a high retention rate for bovine serum albumin (BSA), addressing the limitations of traditional PES membranes.

Implementation Method 1

The method comprises grafting an ionic liquid (IL) onto polyethersulfone (PES) molecular chains through chemical bonds using 60Co-γ radiation

Methodology Applied

Scientific EffectRadiation grafting: Radiation

Implementation Method 2

grafting an ionic liquid (IL) onto polyethersulfone (PES) molecular chains through chemical bonds

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 3

obtaining a porous membrane through immersion-precipitation phase transformation method

Methodology Applied

Scientific EffectPhase transformation: Phase Change

Implementation Method 4

performing Soxhlet extraction on the porous membrane, so as to migrate the grafted IL from an interior of the porous membrane to a surface of the porous membrane to be enriched

Methodology Applied

Scientific EffectExtraction: Liquid-Liquid Extraction

Data Source

PatentUS12233382B2Efficient antifouling and hydrophilic polyethersulfone ultrafiltration membrane and preparation method thereof

Publication Date: 2025.02.25 HANGZHOU NORMAL UNIVERSITY

AI summary

A preparation method of an antifouling and hydrophilic polyethersulfone ultrafiltration membrane includes through the 60Co-γ radiation grafting chemical modification method, evenly distributing an ionic liquid on a surface of a polyethersulfone material, wherein the ionic liquid containing unsaturated bonds is connected with the polyethersulfone material through chemical bonds, and then obtaining an asymmetric porous membrane by the immersion-precipitation phase transformation method, and finally performing Soxhlet extraction on the porous membrane, so as to migrate the grafted ionic liquid from an interior of the porous membrane to a surface of the porous membrane to be enriched, so that the adsorption and antibacterial properties of the porous membrane are improved. A mass ratio of the ionic liquid to the polyethersulfone material is in a range of (2-11):100. The ultrafiltration membrane is an asymmetric porous membrane, and has excellent antifouling properties, good pure water flux and a good BSA retention rate.