Atmospheric Plasma Coating for Filter Media Pathogen Inhibition
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Solution Overview
Problem
Current wet coating techniques for air-permeable filter media are inefficient due to high energy consumption, environmental impact, homogeneity issues, and reduced air permeability, as they often result in thick, non-homogeneous coatings that may not penetrate deeply into porous substrates and can be harmful if not fully adhered.
Innovation Solution
An atmospheric pressure plasma coating method is used to apply a thin, durable, and conformal coating on air-permeable filter media, utilizing a plasma precursor that penetrates deep into the filter's structure, maintaining its air permeability and preventing biological pathogen transfer by destroying, inactivating, or immobilizing pathogens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wet coating techniques are used to apply pathogen-inhibiting substance on filter media, then the coating can be applied to the surface, but the air permeability of the filter is substantially reduced and the coating becomes thick and non-homogeneous
Solution Approach 1:
The patent replaces wet coating techniques with plasma coating technology. The plasma jet delivers coating precursor material in a gaseous state that reacts with the filter media surface to form a thin, uniform coating. This substitution eliminates the need for liquid solutions and drying processes, maintaining air permeability while achieving effective pathogen inhibition through a conformal coating layer.
Solution Approach 2:
The patent changes the physical state of the coating material from liquid (wet coating) to gaseous plasma state. The plasma coating process operates at atmospheric pressure with controlled temperature and flow parameters, enabling precise control of coating thickness and composition. This parameter change results in a thin, homogeneous coating that does not block air flow while maintaining biocidal effectiveness.
2Reliability
If wet coating techniques are used, then coating material can be deposited on the filter surface, but the coating may not penetrate deeply into porous substrates and can be harmful if not fully adhered
Solution Approach 1:
The patent replaces liquid-based wet coating with plasma-based coating. The plasma jet creates a reactive environment where coating precursor material chemically bonds to the filter media surface at the molecular level. This chemical bonding mechanism ensures deep penetration into porous structures and strong adhesion, eliminating the problem of unadhered coating material that characterizes wet coating methods.
Solution Approach 2:
The patent creates a composite structure where the coating precursor material chemically integrates with the filter media matrix. The plasma process enables covalent bonding between the coating layer and substrate, forming a unified composite material system. This integration ensures the coating penetrates deeply into porous substrates and remains firmly attached, preventing detachment and harmful release.
3Reliability
If wet coating techniques are used, then the filter can be treated with pathogen-inhibiting substance, but the process consumes large amounts of water and energy for drying
Solution Approach 1:
The patent replaces wet coating with plasma coating, substituting liquid application and thermal drying with a cold plasma process. The plasma jet delivers coating material in gaseous form that reacts and deposits on the filter surface without requiring evaporation or drying. This eliminates the energy-intensive drying step while maintaining effective pathogen inhibition through the formed coating layer.
Solution Approach 2:
The patent utilizes phase transition of the coating material from gaseous plasma state to condensed coating layer directly on the filter surface. This phase change occurs through plasma cooling and chemical reaction rather than evaporation from liquid state. The process avoids the energy-intensive liquid-to-vapor transition required in wet coating drying, significantly reducing energy consumption while achieving the same protective function.
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 method effectively inhibits airborne transfer of biological pathogens while maintaining the filter's air permeability, ensuring the coated filter media has a pressure drop similar to the untreated media, with a coating thickness that can be controlled and remains effective against viruses like SARS-CoV-2.
Implementation Method 1
an atmospheric pressure plasma coating technique, wherein a coating precursor is inserted in a plasma jet thereby creating a coating precursor-comprising plasma flow
Implementation Method 2
the plasma precursor that penetrates deep into the filter's structure
Data Source
AI summary
A method for plasma coating a compressible structure, includes the steps of: compressing the compressible structure thereby removing air from the compressible structure; and coating the compressed structure according to the following steps: a) ionizing a plasma gas at a temperature of 150° C. or lower, and at about atmospheric pressure, thereby creating a plasma; b) introducing a precursor into said plasma, thereby obtaining a precursor-comprising plasma; c) exposing the compressed structure to said precursor-comprising plasma, thereby forming a coating onto surfaces of the structure.