Electrospun Nanofiber Filter for Reusable PPE
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Solution Overview
Problem
Existing personal protective equipment (PPE) filters, such as N95 facemasks, are typically single-use due to the loss of electrostatic charge during cleaning, making them ineffective after sanitization and contributing to high replacement costs and potential shortages during crises.
Innovation Solution
A reusable filtration element for PPE is developed, featuring a flexible substrate with a layer of electrospun nanofibers, including polymer nanofibers with diameters of 2 micrometers or less, and an anti-pathogen agent. This filtration element is structurally stable up to 300°C, allowing for sanitization through heating and chemical treatment, and achieves a filtration efficiency of >95% against polydispersed NaCl particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single-use PPE filters are used, then filtration efficiency is maintained, but replacement costs increase and shortages occur during crises
Solution Approach 1:
The patent changes the material parameters of the filter by using electrospun nanofibers with specific polymer compositions and controlled morphology. The nanofiber structure with diameters in the sub-micron range creates a physical filtration mechanism that does not rely on electrostatic charge, allowing the filter to maintain its filtration parameters (>95% efficiency) after repeated sanitization cycles
Solution Approach 2:
The patent employs composite materials by combining electrospun nanofibers with a flexible substrate. The nanofiber layer consists of polymer materials selected for their thermal and chemical stability, creating a composite structure that can withstand autoclaving and chemical disinfection while maintaining filtration performance, thus enabling reuse and reducing replacement costs
2Reliability
If electrostatic charge is used for filtration, then filtration efficiency is improved, but the charge is lost during cleaning
Solution Approach 1:
The patent extracts the electrostatic charge mechanism from the filtration process and replaces it with a purely physical filtration mechanism based on nanofiber morphology. By removing the electrostatic component, the filter no longer suffers from charge loss during cleaning, allowing it to maintain its filtration efficiency throughout its entire service life and enabling multiple reuse cycles
Solution Approach 2:
The patent changes the filtration mechanism from electrostatic to physical by controlling the nanofiber structural parameters. The electrospinning process creates nanofibers with specific diameter ranges, porosity, and surface area that provide effective particle capture through diffusion, interception, and inertial impaction, independent of electrostatic charge
3Reliability
If nanofiber layer thickness is increased, then filtration efficiency is improved, but pressure drop increases
Solution Approach 1:
The patent optimizes the nanofiber layer parameters by controlling fiber diameter, porosity, and thickness during electrospinning. The nanofiber mat is designed with specific structural parameters that allow achieving >95% filtration efficiency at thicknesses between 10-100 micrometers while maintaining pressure drop below 25 mmH2O, balancing filtration performance with breathable comfort
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 reusable filtration element effectively filters airborne contaminants with high efficiency while being capable of multiple uses, reducing costs and minimizing the risk of PPE shortages during crises, thus enhancing safety for healthcare professionals and others.
Implementation Method 1
providing a voltage between the flexible substrate and a region adjacent to the nozzle and pumping a material through the nozzle to electrospin a layer of nanofibers onto the flexible substrate
Implementation Method 2
The layer of nanofibers may have a thickness between 10 and 100 micrometers. The reusable filtration element has a filtration efficiency of >95% against polydispersed NaCl particles of average mean mass diameter of 0.26 μm
Data Source
AI summary
Reusable filters for personal protective equipment (PPE) may prevent shortages of PPE and save fabrication time, resources, and money. Disclosed is a method and system for fabrication of nanofiber filter media for PPE. The method includes positioning a substrate to receive nanofibers thereon, providing a voltage gradient in a region of the substrate, and electrospinning nanofibers onto the substrate. The methods and associated systems allow autoclaving of the filter medium at temperatures of up to 300 degrees for sanitizing the filter medium. Additionally, the methods and associated system allow for the inclusion of an anti-pathogen agent in the nanofiber filter media.