DOI: 10.5061/dryad.95x69p8js
title: Electrocharging face masks with corona discharge treatment

description: We detail an experimental method to electrocharge N95 facepiece
 respirators and face masks (FMs) made from a variety of fabrics (including
 non-woven polymer and knitted cloth) using corona discharge treatment
 (CDT). We present practical designs to construct a CDT system from
 commonly available parts and detail calibrations performed on different
 fabrics to study their electrocharging characteristics. After confirming
 the post-CDT structural integrity of fabrics, measurements showed that all
 non-woven polymer electret and only some knitted cloth fabrics are capable
 of charge retention. Whereas polymeric fabrics follow the well-known
 isothermal charging route, ion adsorption causes electrocharging in
 knitted cloth fabrics. Filtration tests demonstrate improved steady
 filtration efficiency in non-woven polymer electret filters. On the other
 hand, knitted cloth fabric filters capable of charge retention start with
 improved filtration efficiency which decays in time over up to 7 h
 depending on the fabric type, with filtration efficiency tracking the
 electric discharge. A rapid recharge for a few seconds ensures FM reuse
 over multiple cycles without degradation.
description: The data was collected using a variety of unrelated
 methods. Structural Integrity data include:
 1) Scanning electron micrographs for surgical masks pre and
 post-corona discharge treatment (CDT) in the form of high resolution TIFF
 images collected using Scanning Electron Microscopy. 2)
 Video movie files showing CDT of face masks at different distances between
 fabric sample and discharge, Infrared imaging of surgical masks undergoing
 CDT, sample video movies of bare electrodes with corona discharge at 30
 frames per second and slow motion, 240 frames per second, and finally a
 video exhibiting the linear guide rail apparatus for raster scan method
 for CDT of fabric samples. 3) Text data include: charge
 measurements and filtration efficiency measurements for various fabric
 samples over a 12 hour duration.
description: We do not anticipate anyone requiring specialized resources to
 use these datasets: 1) Standard image visualization
 software such as Adobe Photoshop or open-source GIMP software suffice for
 visualization of TIFF image files. 2) All videos are
 made available in .MOV format and can be played on standard video players
 such as Apple quicktime. 3) Text data for charge and
 filtration measurements can be used with any standard graphing tool such
 as Origin, Matlab, Sigmaplot, Igor etc. Structure of
 the data set. All data files are presented in a single folder
 <strong>Image
 Files:</strong>
 SMask-PreCDT.tif: This file presents scanning
 electron micrograph for surgical mask pre-CDT.
 SMask-PostCDT.tif: This file presents scanning
 electron micrograph for surgical mask post-CDT.
 Together these two files are presented in figure 7 a and b
 respectively in the manuscript.  
 <strong>Data
 Files:</strong> 
 Cotton-PostCDT-FTIR.txt: Contains FTIR results
 for post-CDT cotton fabric samples at 3 cm vertical distance between
 sample and corona discharge. File structure is tab-limited text with two
 columns. Column 1 lists wavenumber (1/cm) and column 2 lists FTIR
 absorbance in ATR units.
 Cotton-PreCDT-FTIR.txt: Contains FTIR results
 for pre-CDT cotton fabric samples at 3 cm vertical distance between sample
 and corona discharge. File structure is tab-limited text with two columns.
 Column 1 lists wavenumber (1/cm) and column 2 lists FTIR absorbance in ATR
 units. These two files together are presented in figure
 10 of the main mansucript.
 Polyester-PostCDT-FTIR.txt: Contains FTIR
 results for post-CDT polyester fabric samples at 5 cm vertical distance
 between sample and corona discharge. File structure is tab-limited text
 with two columns. Column 1 lists wavenumber (1/cm) and column 2 lists FTIR
 absorbance in ATR units.
 Polyester-PreCDT-FTIR.txt: Contains FTIR
 results for pre-CDT cotton fabric samples at 5 cm vertical distance
 between sample and corona discharge. File structure is tab-limited text
 with two columns. Column 1 lists wavenumber (1/cm) and column 2 lists FTIR
 absorbance in ATR units. These two files together are
 presented in figure 11a of the main mansucript.
 Silk-PostCDT-FTIR.txt: Contains FTIR results
 for post-CDT silk fabric samples at 5 cm vertical distance between sample
 and corona discharge. File structure is tab-limited text with two columns.
 Column 1 lists wavenumber (1/cm) and column 2 lists FTIR absorbance in ATR
 units. Silk-PreCDT-FTIR.txt:
 Contains FTIR results for pre-CDT silk fabric samples at 5 cm vertical
 distance between sample and corona discharge. File structure is
 tab-limited text with two columns. Column 1 lists wavenumber (1/cm) and
 column 2 lists FTIR absorbance in ATR units. These two
 files together are presented in figure 11b of the main
 mansucript.
 ElectretFabrics-Charge.txt: This file lists
 charge measurements performed on various electret, polymeric
 electrocharged filtration facepiece respirators, face masks, and fabrics.
 File structure is tab limited: Column 1 lists time (in hours) in 1 hour
 steps for 12 hour duration, Column 2 charge (in nano coulombs nC) for new
 N95 facepiece respirator, Column 3 charge for used and recharged (using
 CDT) N95 facepiece respirator, Column 4 charge for surgical mask post-CDT,
 Column 5 charge for polypropylene and Column 6 charge for Polystyrene
 fabrics manufactured in-house using the cotton candy method. This data is
 presented in figure 13 of the manuscript.
 KnittedFabrics-Charge.txt: This file lists
 charge measurements performed on various knitted cloth fabrics post-CDT.
 File structure is tab limited: column 1 lists time (in hours) in 1 hour
 steps for 12 hour duration, Column 2 charge (in nano coulombs nC) for
 polyester, Column 3 charge for Cellulose, Column 4 charge for Nylon,
 Column 5 charge for Polyethyelene Terephthalate (PET), and Column 6 charge
 for Polyphenylene Sulfide (PPS). This data is presented in figure 14 of
 the manuscript.
 N95-SM-Penetration.txt: This file lists
 filtration efficiency test measurements performed on N95 facepiece
 respirators and surgical masks. File structure is tab limited: column 1
 lists time (in hours) in 15 minute steps for 12 hour duration, Column 2
 penetration (%) for new N95 facepiece respirator, column 3 penetration for
 used and recharged (using CDT) N95 facepiece respirator, column 4 for a
 pre-CDT surgical mask and column 5 for post-CDT surgical mask. This data
 is presented in figure 15 of the manuscript.
 KnittedCloth-Penetration.txt: This file lists
 filtration efficiency test measurements performed on knitted cloth
 fabrics. File structure is tab limited: column 1 lists time (in hours) in
 15 minute steps for 12 hour duration, column 2 penetration (%) for
 Cellulose (pre-CDT), column 3 penetration for cellulose (post-CDT), column
 5 penetration for polyester (pre-CDT), column 6 penetration for polyester
 (post-CDT), column 7 penetration for Nylon (pre-CDT), column 8 penetration
 for Nylon (post-CDT), column 9 penetration for PET (pre-CDT), column 10
 penetration for PET (post-CDT), column 11 penetration for PPS (pre-CDT)
 and column 12 penetration for PPS (post-CDT).
   <strong>Video
 Files:</strong>
 CMask-CDTburn.MOV: This file shows singeing
 (observed as yellow flashes) of threads in a cotton face mask when the
 corona discharge (blue glow) is in contact with fabric.
 M1.mov: Corona discharge, transverse electric
 wind observed as blue glow, and discharge sparks observed from bare
 electrodes at 30 frames per second.
 M2.mov: Corona discharge, transverse electric
 wind observed as blue glow, and discharge sparks together with trichel
 pulses heard as semi-periodic clicks from bare electrodes at 240 frames
 per second. M3.mov: The electrode
 system mounted on a linear guide rail that achieves raster scan of CDT on
 fabric samples. SMask-7cm-CDT.MOV:
 Surgical mask undergoing CDT at a 7 cm vertical gap between mask and
 discharge. SMask-3cm-CDT.MOV:
 Surgical mask undergoing CDT at a 3 cm vertical gap between mask and
 discharge. SMIR-3cm.MOV: Infrared
 thermal imaging video for surgical mask undergoing CDT at a 3 cm vertical
 gap between mask and discharge.
 SMIR-7cm.MOV: Infrared thermal imaging video
 for surgical mask undergoing CDT at a 7 cm vertical gap between mask and
 discharge.