Porous Filter Membranes with Copper Coating for Virus Inactivation

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Solution Overview

Problem

Existing air filtration technologies struggle to effectively inactivate airborne viruses like SARS-CoV-2 without significantly reducing the permeability of the filter membranes, as most solutions focus on nanoparticle-based materials that can clog pores and decrease airflow.

Innovation Solution

A porous filter membrane with a ceramic base and a copper-based anti-viral coating deposited via sputtering, maintaining membrane porosity and ensuring high virus retention and inactivation efficiency by using a nanocrystalline metallic coating that does not invade internal pore walls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nanoparticle-based materials are used for virus inactivation, then antiviral protection is improved, but membrane porosity and airflow are reduced

Engineering Contradiction:
Improveantiviral protectionVSAvoidairflow
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies porous anodic alumina substrate with controlled pore size (10-100 nm) and porosity (30-70%) to maintain airflow while providing virus retention. The porous structure allows air passage while the pore walls provide surface area for virus capture, resolving the contradiction between filtration efficiency and airflow.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent creates a composite structure combining porous anodic alumina substrate with metallic copper coating. The alumina provides porous support structure for airflow, while the copper layer provides antiviral activity. This composite approach allows both high airflow and effective virus inactivation.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a metallic coating is deposited on the membrane surface, then virus inactivation efficiency is improved, but pore clogging and pressure drop increase

Engineering Contradiction:
Improvevirus inactivation efficiencyVSAvoidpressure drop
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent applies metallic copper coating only on the outer surface of the porous membrane (5-500 nm thickness), leaving the internal pore structure open. This localized coating provides virus inactivation at the entry point while maintaining pore openness for airflow, preventing pressure drop increase.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent controls the metallic coating thickness parameter (5-500 nm) to be thin enough to avoid pore clogging while sufficient for antiviral activity. This parameter optimization resolves the contradiction between virus inactivation efficiency and pressure drop.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the metallic coating thickness is increased, then antiviral properties are enhanced, but membrane permeability decreases

Engineering Contradiction:
Improveantiviral propertiesVSAvoidmembrane permeability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent optimizes the metallic coating thickness parameter within 5-500 nm range, finding the optimal balance point where sufficient antiviral copper is deposited without blocking the porous structure. This parameter control maintains both antiviral properties and membrane permeability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies a thin partial coating (5-500 nm) rather than a thick complete coating, which is sufficient to provide antiviral activity at the virus entry point while leaving the pore structure open for airflow. This partial action approach avoids excessive coating that would block pores.

Inventive Principle:
Principle #16Partial or excessive 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 solution achieves high virus inactivation efficiency (above 90%) while maintaining airflow efficiency, retaining viruses on the surface long enough to inactivate them, with a compact design suitable for HVAC systems and respiratory protection equipment.

Implementation Method 1

an anti-viral metallic based coating with a thickness between 50 nm and 3000 nm... deposited via sputtering

Methodology Applied
Scientific EffectSputtering: Sputtering

Data Source

PatentEP4472757B1Porous filter membranes comprising a metallic based coating with Anti-viral properties
Publication Date: 2026.04.01 CTCV - CENTRO TECNOLÓGICO DA CERÁMICA E DO VIDRO
  • EP4472757B1 patent drawingFigure 1~2
  • EP4472757B1 patent drawingFigure 3~4
  • EP4472757B1 patent drawingFigure 5~6

AI summary

The present application discloses a porous filter membrane and an assembly of porous filter membranes for air filtration and inactivation of virus. The porous filter membrane comprises a metallic based coating with anti-viral characteristics. The porous filter membrane is made of inorganic materials such as ceramics, comprises pores in the micro/submicro/nano size range, and further comprises a thin film metallic based coating. The present invention can retain and inactivate airborne viruses, such as SARS-CoV-2, and is suitable to be used in Heating, Ventilating and Air Conditioning Systems (HVAC), health-care ventilators, respiratory protection equipment and any other device or equipment suitable for filtering air.