CA3174368A1

CA3174368A1 - Electrospun nanofibrous polymer membrane for use in personal protective equipment

Info

Publication number: CA3174368A1
Application number: CA3174368A
Authority: CA
Inventors: Feng Guo; Sherif SOLIMAN
Original assignee: Matregenix Inc
Current assignee: Matregenix Inc
Priority date: 2020-03-31
Filing date: 2021-03-31
Publication date: 2021-10-07
Also published as: KR20230076803A; CN116034156A; WO2021202820A1; JP2023520541A; EP4127150A1; EP4127150A4

Abstract

An electrospun polymer nanofibrous membrane that provides high filtering efficiency and excellent porosity is disclosed herein. The membrane may be treated with one or more antimicrobial or antiviral agents. The treatment may preferably be a coating of one or more antiviral agents on the surface of the membrane. Alternatively, one or more antiviral agents may be impregnated into the nanofibrous membrane. The membrane may additionally or alternatively be impregnated with one or more metal-organic frameworks (MOFs). The membrane has a high filtering efficiency and sufficient porosity to provide breathability characteristics. The membrane is suitable for use in making facemasks and respirators that are highly resistant to infectious pathogens and/or other small particulates.

Description

ELECTROS.PU.N NANOEIBROUS POLYMER MEMBRANE
FOR USE IN PERSONAL PROTECTIVE EQUIPMENT
cROSS-RE FE RENCE TO RELATED APPLICATIONS
[00011 This application claims the benefit of, and priority to, U.S.. Provisional Patent:
.Application Serial Nos. 631002435,, filed on March. 31õ 2020, and 63/1.16,799, filed on November 20, 2020, th, disclosures of which are hereby incorporated in their entireties herein by reference..
BACKGROUND
Field of the Invention 10002! The present disclosure relates to materials for use in personal protective equipment.
Description of the Related Art 10043.1 Community acquired respiratory virus (CARV). infections include infections caused by a variety Of vituSeS, including coronaviraseS, rhinoviruses, influenza .viruses, and inetapnentuovinas. See, eg.,õ- VerSluys, A.B., a at 'Morbidity and: Mortality Associated With Respiratory Virus infections in AllOgenele Flematopoietic Cell 'Transplant Too Little Defense or Harmful Immunity?" .Froni. Microbia, 2018, 9, .2795-279:5, doi:10.3389/finieb.2018.02795.. Many ARV infections result in significant morbidity and mortality.. For example, the Spanish flu pandemic of 1918 killed between 20 million and 50 million people worldwide_ Roost,.D. "Why the *cond. Wave of the 1918 Spanish Flu Was SQ. Deadly," :IiisIoty.eoni, 2029 (available at:
https://www.history:cominewsispanish-fht-second-wave-resurgence). In addition influenza pandemics are known to emerge cyclically.
The current eoronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus.2 (SARS-CoV-2), has become the 'foremost global health problem of the current century and is the worst pandemic since the Spanish flu pandemic.
l00.041 Infectious respiratory pathogens are typically transmitted by droplet, aerosol, or airborne transmission of particles expelled from the respiratory tract of an infected person by coughing or sneezing, or in sonic eases by simple exhalation. To prevent this form of transmission, facernasks and respirators have been developed that either mechanically intercept the infectious particles or that disarm the infectious particles using a variety of mechanisms. Therefore, many research and development efforts have been made to enhance the filtering efficiency of facemasks and respirators.

The COVID-19 pandemic has highlighted the need for functional protective textiles for a variety of applications. Functional protective textiles are particularly important.
for use in protective clothing for medical professionals, field workers, and soldiers. cee, e.g., Zhu, Q., e al. 'AQC Functionalized CNCs/PVA-co-PE Composite 'Nano:fibrous Membrane with Flower-Like Microstructures for Photo-Induced Mufti-Functional Protective Clothing,"
Cellulose, 2018, 25, 4819-30, doi: 10.-1007/s10570-018-1881-5; Liu, Y., t.4"
"UV-Crosslinked Solution Blown PVDIF Nanofiber Mats for Protective Applications,"
Fibers Poly'''. 2020, 21, 489-97, doi: 10.1007/s12221-020-9666-5.

To limit dermal exposure to airborne solid particles, health and safety regulatory agencies have published good practice guidelines, and wearing personal protective equipment (PPE) has been. recommended to minimize exposure to a variety of hazards.
Chemical and biological protective clothing (CBPC) are widely used and are considered the most economical among PPE options. For airborne nanomaterials, type 5 CRPC is considered the last line of defense against such dangers, as it provides full body protection against airborne solid particulates according to the ISO 13982-1 and ISO 13982-

2 standards.
See International Organization for Standardization (ISO) 13982-1:2004;
International Organization for Standardization (ISO) 13982-2:2004.

Nonwoven and woven materials commonly used as the base for type 5 C,BPC
have several disadvantages such as poor permeability and filterability. See, e.g., Liu, Y. et al., supra; Wingert, L., et al. "Filtering Performances of 20 Protective Fabrics Against Solid Aerosols,"./. ()carp. Environ. lin. 2019, 16, 592-606.
(00081 Current commercially available faeemasks and respirators either do not have adequate filtering efficiency to intercept the infectious particles or have insufficient air permeability to allow frequent and convenient use.
Lee, S., et al. "Reusable Polybenzimidazole Nanotiber Membrane Filter for Highly Breathable .PM2.5 Dust :Proof Mask," .4 CS App!. Mater: Interfaces. 2019, 11, 2.750-57, doi: 10.102 liacsami.8b19741.

Moreover, the recent .COVID-19 pandemic has increased interest in antiviral.
membrane development for facemasks and respirators which will exterminate pathogens contacting the faeetnaSk or respirator. This will prevent infectious particles to be transferred to another surface by inadvertent contact of the ma.* with other surfaces or by the wearer touching the exterior surface of the musk. by hand.
100091 Numerous antiviral agents are known that may be suitable for use in coatings or that may otherwise be integrated into personal protective equipment.. See, e.g., Tran, D.N., cv al. "Silver Nanoparticles as: Potential Antiviral Agents against African Swine Fever Virus,"
Mater. Res. .Express, 2020, 6(12), doi: 10:1088/2053-1591/ab6ad8; Moreno, MA., et al "Active Properties of Edible Marine Polysaccharide-Based Coatings Containing Jarrett nitida Polyphenols Enriched Extract," Food Hydrocoll. 2020, 102, 105595, doi:
10.1.0166.foodhyd.201.9.105595; Nilsen, A. "Natural Product-Based Fabrication of Zinc-Oxide Nanoparticles and Their Applications," In Nanotnaterials and Plant Potential, 2019, 193-219, Springer; Cheng, C., .et al. "Functional Graphene Nanornuterials Based Architectures: Biointeractions, Fabrications, and Emerging Biological Applications," Orem.
Rev. 2017, 117, 1826-1914; Zhang, D.-h., et al. In Silica Screening of Chinese Herbal Medicines with the Potential to Directly Inhibit 2019 Novel Coronavirus," J.
integr. Med.
2020,18, 152-8, doi: 10.10161joim,2020.02.005; U.S.. Patent Nos. 9,963,611 and 8,678,002.
100101 Various techniques for producing nanofiber membranes are known, including electrospinning, phase inversion, interfacial polymerization, stretching, and track-etching.
Electrospinning is a very useful technique that provides efficiency and uniformity of pore size. See., e.g., Ray, S.Sõ et al. "A Comprehensive Review: Electrospinning Technique for Fabrication and Surface Modification of Membranes for Water Treatment Application," RS(.' Adv. 2016, 6(88), 85495-85514, doi: 10.1039/C6RA14952A. Electrospinning is a process that uses an electric field to generate continuous fibers on a micrometer or nanometer scale.
Electrospinning enables direct. control of the microstructure of a. scaffold, including characteristics such as the fiber diameter, orientation, pore size, and porosity.
100111 Electrospun nanofibers have a wide range of applications.
These include antibacterial food packaging, biomedical applications,. and. environmental applications. See, e.g., Lin, 1..., et al. "Cold Plasma Treated Thyme Essential Oil/Silk Fibroin Nanofibers against Salmonella Typhimurium in Poultry Meat," Food Packag. Shelf Lye, 2019, 21,

3 100337; Zhu, Y., et al. "A Novel Polyethylene Oxide/Dendrobium giticinak Nanofiber;
Preparation, Characterization and Application in Pork Packaging," Food Packag.
Shelf Life, 2019, .21, 100329; Surendhirart, D., et al. "Encapsulation of Phlorotannin in Alginate/7EO
Blended Nanolibers to Preserve Chicken Meat from Salmonella Contaminations,"
Food Packag Shelf Life, 2019, 21, 100346; Khan, .M.Q., et al. "The Development of Nanofiber Tubes Based on Nanocomposites of Polyvinylpyrrolidone Incorporated Gold Nanoparticles as Scaffolds Ibr Neuroscience Application in Axons," Text Res. .1. 2019, 89, 2713-20, doi:
10.1.177/0040517518801185; Utah, S., et al. "Antibacterial Properties of In Situ and Surface Functionalized Impregnation of Silver Sulfadiazine in Polyacrylonitrile Nanofiber Mats," ml.
Nanomedirine, 2019, 14, 2693-2703, doi; 10.2147/L1N.S197665; Khan, M.Q., et at "Fabrication of Antibacterial Electrospun. Cellulose Acetate/Silver-Sulthdiazine Nanofibers C:omposites for Wound Dressings Applications," Polym. Test. 2019, 74, 39-44.
Doi:
10..1016/j.polymertesting.2018.12.015; Ray, &S., et at õwpm.
100.121 Electrospun nanotiber textiles have been considered promising candidates for CBM. S'ee, e,g, Lee,. S.. et at "Transport Properties of Layered fabric Systems Based on Electrospun Nanolibers," Fibers Polym. 2007, 8, 501-06; Bagherzadeh, R.., et al. "Transport Properties of Multi-Layer Fabric Based on Electrospun Nanofiber M:ats as a Breathable Barrier Textile Material," Text. Res. .1: 2012, 82, 70-76..
100131 Electrospun polymeric nanalibers may exhibit very high external surface area, excellent water vapor transport- properties, and good mechanical strength.
See, e.g, Huang, Z., et at "A :Review on Polymer Nanofibers by Electrospinning and Their Applications in Nanocomposites," Compos..Sei. Technol, 2003, 63, 2223-53.
100141 Fabrication of textiles front eiectrospun polymeric nanofibers generates ultrathin, lightweight, and high tensile strength textiles. See, e.g., Lee, S., et at, $apra;-Dhineshbabu, N. R., et al. "Electrospun MgO/Nylon 6 Hybrid Nanofibers for Protective Clothing," Nano-Micro Utt. 2014, 6, 46-54;. Han, Y:, et al. "Reactivity and Reusability of Immobilized .Zinc Oxide Nanoparticles in Fibers on Methyl Parathion Decontamination," Text, Res.
J. 2013, 86, 339-49.
100151 Chen, et al. disclose .10nctionalized nanofiber mats generated by integrating nucleophilic oxime moieties through electrospinning of polyacrylamidoxime (MAO) and PAN. These functionalized nanofiber mas exhibited a substantial ability to hydrolyze

4 chemical nerve agents. Chen, L., et al. "Multifunctional Electrospun Fabrics via Layer-by-Layer Electrostatic Assembly for Chemical and Biological Protection," Chem.
Mater. 2010, 22, 1429-36.

Choi, et at disclose fabricated polyurethane nanofibers flinctionalizt..d by N-chloro hydantoin (NCH-PU). These nanofibers successfully decontaminated a simulant for V-type nerve gas (demeton-S-methyl). Choi, 3., et at. "N-Chloro Hydamoin Functionalized Polyurethane Fibers Toward Protective Cloth Against Chemical Warfare Agents,"
Polymer, 2018, 138, 146-55.

Various metal nanoparticles integrated nanofibers have been disclosed, that have been proposed for use in protective clothing and face masks for shielding against harmful chemicals and biological agents. See, e.g., Ramaseshan, Rõ ci aL
Titanate Nanofibers for the Detoxification of Chemical Warfare Simulants, .1. Am. Ceram. Sae.
2007, 90, 1836-42.
1.00181 Lee, at al. disclose functional PAN nanofiber webs to protect users from a simulant of a chemical warfare agent (CWA). Lee, I., et al. "Preparation of Non-Woven Nanofiber Webs lir Detoxification of Nerve Gases," Polymers 2019, 179, 121664.
(00191 Zhao, et al. disclose metal-organic. frameworks (MC)Fs) integrated into polyamide-6 nanofibers. The MOF-nanofiber composites exhibited extraordinary reactivity for detoxifying CWAs. Zhao, I., et al. "Ultra-Fast Degradation of Chemical Warfare Agents Using MOF--Nartofiber Kebabs," Angew. Chem. Mt, Ed. 2016, 55, 13224-28.

Antiviral agents have been incorporated into electrospun fibers for prevention of HIV infection. Grooms, T. N., et al. "Gritlithsin-Modified Electrospun Fibers as a Delivery Scaffold To Prevent HIV Infection," Antimierab. .Agettft Chem other. 2016, 60, 6518.

There remains a need for new materials to develop high-performance membranes with antiviral .and other anti-pathogenic properties that have high filtering efficiency and breathability for use in facemasks and respirators.
SUMMARY
[00221 An electrospun polymer nanofibrous membrane that provides high tittering efficiency and excellent porosity is disclosed herein.

100231 The membrane may be treated with one or more antimicrobial or antiviral agents.
In some embodiments, the membrane may be treated. with an antiviral agent selected from the group consisting of graphene,. nanoparticles, nanocomposites, multivalent metallic ions, and medicinal or other extracts from natural products. The treatment may preferably be a coating of one .or more antiviral agents on the surface of the membrane.
Alternatively, one or more antiviral agents may be impregnated into the nanofibrous membrane.
100241 The membrane may additionally or alternatively be impregnated with one or more metal-organic frameworks (M0Fs). The one or more MOFs may, for example, be one or more zirconium MON. The M.OFs may provide filtration of chemical warfare agents (CWAs) and other toxic chemical agents and, in some embodiments, may also provide additional or alternate filtration of small particulates and pathogens.
100251 The disclosed membrane may preferably have a high filtering efficiency. The porosity of the disclosed membrane may preferably be sufficient. to provide breathability characteristics suitable for use as a facemask or respirator. The disclosed membrane. is suitable for use in making facemasks and respirators that are highly resistant to infectious pathogens and/or other small particulates.
BRIEF DESCRIPTION OF THE DRAWINGS
100261 FIG. I shows representative scanning electron microscopy (SEM) images of embodiments of the disclosed nanofibrous polymer membranes.
100271 FIG. 2 shows fiber diameter measurements and distribution for representative samples of an embodiment of the disclosed nanofibrous polymer membrane.
100281 FIG. 3 shows pore size distribution. for representative samples of an embodiment of the disclosed nanofibrous polymer membrane as determined by mercury porosimeter analysis.
100291 FIG. 4 shows average porosity and the distribution of mean porosity for representative samples of an embodiment of the disclosed nano-fibrous polymer membrane.
100301 FIG. 5 shows mechanical tensile strength test results for representative samples of an embodiment of the disclosed nanofibrous polymer membrane.
100311 FIG. 6 shows filtration efficiency test results for representative samples of an embodiment of the disclosed nanofibrous polymer membrane.

10032j FIG. 7 shows latex filtration test results kir representative samples of an embodiment of the disclosed nanofibrous polymer membrane.
100331 FIG. 8 Shows viral filtration efficiency test results for representative samples of an embodiment of the disclosed nanofibrous polymer membrane.
[00341 FIG. 9 shows bacteria filtration efficiency test results for representative samples of an embodiment. of the disclosed nanolibrous polymer membrane.
100351 MG. 10 shows flammability test results for a representative sample of an embodiment of the disclosed nanofibrous polymer membrane.
100361 FIG. 11 shows antiviral properties test results for representative, samples of an embodiment of the disclosed nanofibrous polymer membrane.
(00371 FIG. 12 shows antibacterial properties test results for representative samples of an embodiment of the disclosed nanofibrous polymer membrane.
100381 FIG. 13 shows how filtration efficiency is affected by the flow rate of aerosols through the membrane.
100391 FIG. 14 shows how the pressure drop across the membrane is affected by the flow rate of aerosols through the membrane.
DETAILED OESCRIPTION
100401 An electrospun polymer nanolibrous membrane that provides high altering efficiency and excellent porosity is disclosed herein.
100411 The membrane may be treated. with one or more antimicrobial or antiviral agents.
In some embodiments., the membrane may be treated with an antiviral agent selected from the group consisting of graphene, nanoparticles, nanocomposites, multivalent metallic ions, and medicinal or other extracts from natural products. The treatment may preferably be: a coating of one. or more antiviral agents on the surface of the membrane.
Alternatively, one or more antiviral agents may be impregnated into the nanofibrous membrane.
100421 The membrane may additionally or alternatively be impregnated with one or more metal-organic 'frameworks (MOB). The one or more MOB may, for example', be one or more zirconium MOB. The MOB may provide .filtration of chemical warfare agents (CWAs) and other toxic chemical agents and, in some embodiments, may also provide additional or alternate filtration of small particulates and pathogens.

10043j The disclosed membrane may preferably have a high filtering efficiency. The porosity of the disclosed membrane may preferably be sufficient to provide breathability characteristics suitable for use as a facemask or respirator. The disclosed membrane is suitable for use in making faeemasks and respirators that are highly resistant to infectious pathogens and/or other small particulates.
100441 The disclosed membrane may preferably have a filtering efficiency of at least 95%, more preferably at least 98%, even more preferably at least 99%, and most preferably at least 993%.
100451 The disclosed membrane may preferably be capable of intercepting and exterminating infectious pathogens on its surfaces.
100461 in some preferred embodiments, the disclosed membrane is non-flammable.
(00471 The disclosed membrane may be. suitable for the production of non-flammable high-performance textiles.
IONS' In some preferred embodiments, the disclosed membrane is.
ultrathin and ghtwei 100491 In some preferred embodiments, the disclosed membrane does not degrade upon exposure to water or selected organic solvents such as ethanol or .acetone.
Thus, products made using the membrane may be washed and reused.
100501 In some embodiments, the nanofibrous polymer membrane may be made from polyvirtylidene fluoride (PVDF). In some alternate embodiments., the nanofibrous polymer membrane may be made from one or more Tecophilierm thermoplastic.
polyurethanes (TPUs). In some other alternate embodiments, the nanofibrous polymer membrane may be made from a blend of polyvinylidene fluoride and one or more Tecophilierm thermoplastic polymethanes.
100511 The nanofibrous polymer membrane. may be made using electrospinning techniques. A polymer is dissolved. in a. solvent prior to electrospinning. in some embodiments, the solvent may preferably be selected from the group consisting of dimethylforniamide (DMO, dimethylacetamide (DMA), hexalluoroisopropancil acetone, water, or a combination thereof.
100521 in some embodiments, a surthetant may be added to the polymer solution.
Adding a surfactant to the polymer solution may promote a smaller fiber diameter and thus yield a membrane which has a smaller pore size and thus higher filtration efficiency. In some preferred. embodiments, the surfactant may be one or more surfactants selected from.
the group consisting of cetrimonium bromide (CTAB), lauramidopropyl betaine (I.APB), and alpha olefin suifonate (AOS).
[00531 In some embodiments, a salt or salt solution may be added to the polymer solution. Adding a salt or salt solution to the polymer solution may promote formation of thinner and more uniform fibers and may also reduce bead ibrmation. By increasing charge density and conductivity, the presence of salts in the polymer solution promotes elongation of the spinning jet, which leads to the generation of thinner fibers. in some preferred embodiments, the salt or salt solution may be one or more salts or salt solutions selected from the oroup consisting of alkali metal halides and phosphate-buffered saline (PBS). In some more preferred embodiments, the salt or salt solution may be one or more WO
selected from.
the group consisting of sodium chloride (NaCI), lithium chloride (Liel), and potassium chloride (Ka).
100541 The nanofibrous polymer membrane may be a single layer membrane or may alternatively be an integrated multiAayer membrane. In some embodiments, the membrane may be composed of multiple integrated layers with distinguishable microstructure characteristics. A. membrane that is composed of multiple integrated layers may provide enhanced filtration efficiency and high breathability. The enhanced filtration efficiency of an integrated multi-layer membrane may result from superior barrier protection against small pathogen particles.
100551 In some embodiments, the integrated multi-layer membrane.
is composed of two layers with different pore sizes. In some alternate embodiments, the integrated multi-layer membrane is composed of three layers with two layers of equal pore size separated by a layer with a different pore size. The pore size may preferably be between I and 20 1AM for the Layer(s) with smaller pore size and between 20 and 200 gm for the layer(s) with larger pore size.
100561 In embodiments .with three layers having two layers of equal pore size separated by a layer with a different pore size, the layers of equal size may preferably have a larger pore size and the layer in between these two layers may preferably have a smaller pore size.
This configuration decreases the likelihood of delamination and also decreases the pressure drop that is generated as a gas passes through the multi-layer membrane, which corresponds to increased breathability, without. appreciably reducing the filtration efficiency of the membrane.
100571 In some other alternate embodiments, the integrated multi-layer membrane is composed of three layers with three different pore sizes.
100581 The pore size of the layers in integrated multi-layer membranes may be adjusted by adjusting the viscosity of the polymer solution and the electrospinning process conditions.
Elextrospinning process conditions may be adjusted to further stabilize the spinning: jet used in the elmtrospinnimt setup. Solutions with lower viscosity will typically generate smaller pore size layers, and solutions with higher viscosity will typically generate larger pore size Layers.
100591 In so.nrie embodiments, the mechanical integrity and binding forces between layers of the membrane may be enhanced by electrospraying short fibers prior to electrospirming the subsequent layer. In some other embodiments, the mechanical integrity and binding forces between layers of the membrane may be enhanced by electrospinning wet fibers by decreasing the screen distance to generate a "tacky surface" prior to electrospinning the subsequent layer.
(OEM In some embodiments, the disclosed nanofibrous polymer membrane may be laminated onto a textile material. Alternatively, the nanofibers may be directly electrospun on nonwoven fabrics such as polyethylene terephthalate (PET), polypropylene (PP), and PET
copolymers. The use of PET copolymers results in enhanced adhesion between the nanofibers and. textile, which thereby reduces peeling.
006.11 The disclosed .nanofibrous polymer membrane may be treated with an anti-pathogenic agent such as an antiviral agent. selected from the group consisting of graphene, nanoparticles, nanocomposites, multivalent metallic ions, and medicinal or other extracts from natural products. The nanoparticles may preferably be metal nanoparticles such as silver nanoparticles or zinc nanoparticles. The nanoeomposites may preferably be silver-doped titanium dioxide nanomaterials. The multivalent metallic ions- may preferably be metal ions such as C.u24. or Zn.2'. cations. The extracts from natural products may preferably be licorice extracts.

100621 The anti-pathogenic agent(s) may be physically coated on the surface of the membrane. The coating may be applied using chemical or electrochemical methods such as atomic layer deposition, vapor deposition methods such as physical vapor deposition (PVD) or chemical vapor deposition (CVD), spray coating methods such as plasma spraying or spray painting, or physical coating methods such dip-coating or spin-coating.
100631 The anti-pathogenic agent(s) may alternatively be incorporated into the membrane by blending the anti-pathogenic agent(s) into the polymer solution prior to electrospinning, thereby generating a membrane impregnated with the anti-pathogenic agent(s).
100641 In some embodiments, the disclosed nanofibrous polymer membrane may be impregnated with one or more metal-organic frameworks (MOFs), such as zirconium MOFs.
The MOFs may be incorporated into the membrane by blending the MOFs into the polymer -solution, prior to electrospinning, thereby generating a membrane impregnated with the MOFs.
100651 In some embodiments, MOP-impregnation into the membrane may be in addition to coating with or impregnation of anti-pathogenic agent(s). In other embodiments, MOF-impregnation into the membrane may be an alternative to coating with or impregnation of anti-pathogenic agent(s). Membranes impregnated with MOFs may provide filtration, of chemical warfare agents (CWAs) and other toxic chemical agents. In some embodiments, membranes impregnated with MO.E.s may also exhibit antiviral, antibacterial, or other anti-pathogenic preperties.
100661 Thus, it is not intended that the MOFs described herein are necessarily distinct from the anti-pathogenic agents, such as antiviral or antibacterial agents, described herein.
Rather, the anti-pathogenic. agent may be a MOF or may alternatively be one of the other anti-pathogenic agents described herein. It is also not intended that the MOFs described herein will necessarily exhibit antiviral, antibacterial, or other anti-pathogenic properties.
MOFs that are impregnated in the disclosed membranes may provide filtration of Chemical warfare agents (CWAs) and other toxic chemical agents but, in some embodiments, may not exhibit antiviral, antibacterial, or other anti-pathogenic properties or provide filtration or small particulates, 100671 To increase the breathability of textile materials coated with the disclosed nanofibrous polymer membranes, multiple nanofiber layers of differing thicknesses may be electrospun on the same or opposite sides of textile materials. A textile material that is in the form of a textile material roll may be coated with one or more nanofiber layers by electrospiiming. En some embodiments, one or more first nanofiber layers are.
electrospun on a fuBt side of a textile material at a first winding speed, the textile material roll is flipped, and one or more second nanofiber layers are electrospun on a second side of the textile material at a second winding speed, where the first winding speed is different from the second winding speed. In other embodiments, one or more first nanofiber layers are electrospun on a first side of a textile material at a first winding speed, and one or more second nanofiber layers are then eleetrospun on the first side of the textile material at a second winding, speed, where the first winding speed is different from the second winding speed. In yet other embodiments, one or more first nanofiber layers are electrospun on a first side of a textile material at a first winding speed, one or more second nanofiber layers are then electrospun on.
the first side of the textile material at a. second winding speed, the textile; material roll is then flipped, and one or more third nanofiber layers are eleCtrospun on a second side of the textile material at a third winding speed, where the first winding speed is different from the second.
winding speed. In yet other embodiments, additional .electrospinning steps may be added to include additional nanofiber layers of different thicknesses on one or both sides of the textile material.
100681 A .facemask or respirator made from the disclosed nano fibrous polymer membrane is also disclosed herein. The fitcemask or respirator may preferably have a high filtration capacity and suitable breathability characteristics for comfortable use by a wearer.
The disclosed facemask or respirator may preferably have a filtering efficiency of at least 95%, more preferably at least 98%, even more preferably at least 99%, and most preferably at least 99.9%.
100691 A method of making a beerriask or respirator from the disclosed nanofibrous polymer membrane is also disclosed herein. The method may preferably allow the anti-pathogenic, physical, chemical, and mechanical properties to be fine-tuned according to the requirements of the specific application.

Sample Preparation 100701 The fbilowing sample preparation materials and methods are exemplary. Other suitable materials and methods may be used within the scope of the invention.
100711 Materials. Multiple Tecophilicill thermoplastic polyorethane.s (PEU) were purchased from Lubrizol. Knyar 2801 polyvinylidene fluoride (PVIV) was put-Chased from Arkema. Hexafluoroisopropanol (HFIP) was purchased from Oakwood. Products Inc.

Dimethylacetarnide (DMAc), acetone, cetrimonium bromide (CTAB), and lithium chloride (LICI) were purchased from Fisher Scientific: Silver nanopartcies (15 nm) were purchased from Skyspring Nanomaterials. ZnO and CuO (Zn-Cu) were purchased from Sigma Aldrich.
Ag-doped T.102 (Ag-T102) nanoparticles were provided by :1M Material Technology inc.
I..icorice extracts were provided by NSI. USA. Inc.
1007.21 Solution Preparation. PEU polymers were added to EIFIP to create 7 and 15 w/v solutions. 15.5% wt !WM was dissolved in 3:1 DMAchieetone containing 0.85%
CIAB
and 0.04% LIG. All, of the solutions were mixed on a stirring plate until the polymer pellets/powder completely dissolved.
100731 Antiviral Treatment. Two antiviral treatment methods were used: (1) the membranes were submerged in an aqueous dispersion containing antiviral particles, Of (2) the antiviral agents were added to the polymer solutions to directly fixbricate antiviral nanoffbrous membranes. The antiviral agents used were 2.!A citric acid .and silver, Ag-TiO2 and Zn-Cu nanoparticles, and licorice extracts.
100741 Membrane Fabrication. The membrane fabrication process was a roll-to-roll system, where a textile material was wound from one side to the other side and the nanofiber layer was laminated on. the textile during the winding process. The thickness of the nanofiber layers was controlled by controlling the winding speed.
CharaeterizatiOn of Representative Samples 100751 To investigate the feasibility of using the disclosed nanofibrous polymer membranes in facemasks and respirators, the morphology, fiber diameter, filtering efficiency, porosity, wettability, mechanical strength, and antiviral activity of representative samples of an embodiment of the disclosed nanofibrous polymer membrane was characterized.

10076i Nanofibrous polymer membranes were characterized using scanning electron microscopy (SEM) imaging. Fla 1 shows representative SEM images of an embodiment of the disclosed natiofibrous polymer membrane. The larger images show 2000X
magnification, while each inset shows the respective 5000X magnification image. As shown in .FIG. 1, the internal and external surfaces of each nanofiber membrane display consistent morphology between samples. In addition, the nanofibrous membranes show good orientation and are free of breading, splitting, and other undesirable morphological features.
100771 FIG. 2 shows fiber diameter measurements and distribution for representative samples of an embodiment of the disclosed nanofibrous polymer membrane. The average fiber diameter of representative samples was 0.224 um, with a median fiber diameter of 0.210 tm and a standard deviation of 0.106. The average orientation was 79 , and the area coverage was 16%.
100781 FIG. 3 shows pore size distribution for representative samples of an embodiment of the disclosed nanofibrous polymer membrane as determined by mercury porOsimeter analysis. The mean pore diameter was found to be 0.0025 Am.
100791 FIG. 4 shows average porosity and the distribution of mean porosity for representative samples of an embodiment of the disclosed nanofibrous polymer membrane.
The average porosity as determined by gravimetric measurements was shown to be distributed around a Center point of 78.5%. As shown in FIG. 4, all samples showed consistent porosity in the range of 75% to 83%. High porosity of the membrane is a critical requirement to increase the breathability of a facemask. or filter made from the membrane.
100801 FIG. 5 shows mechanical tensile strength test results for representative samples of an embodiment of the disclosed nanabrons polymer membrane.
100811 A representative sample of an embodiment of the disclosed nanofibrous polymer membrane was also tested for filtration efficiency. The observed efficiency was 99.61% for 30 Limb, with a pressure loss of 1..265 mbar, and 99.85% for 95 Limin. with a pressure loss of 4.3 mbar.

Table I shows a summary of test results for representative samples of an embodiment of the membrane.

Laboratory Test Standard Results AD International filtration F. MCierte.* NOW MOO:
filuviort effiCiency:
Nelson Labs Synthetic B1ood. Penetration ASTM F2100 no penetration Nelson Labs: Flammability Test .... ASTM F210.1. Class I
Nelson I..abs Cytotoxicity ASTM F2102 Grade 0 mHHmmommia Nelson Labs Pitetici*T litratinn:Efficiency ASTM 1 210:11 averace 99%.
Nelson Labs Virus Filtration Efficiency ASTM F2104 average 993%
Nelson Labs Bacterial :Filtnition Efficiency :ASTM:F.2:)05 average )9$%
:
MicroChem MS2 Bactetiophage AATCC 100 >99% reduction Mierciebem titirnau:Cloranavirti:229E AA1CC 100 >99..i9%:1*luction . .
Matregenix E. cola ASTM E2315 >90:9%
reduction . :
Mat regenia: GI P Lentivittis AATcC:100 >99 oredtiction SEM
fiber diameter analysis Matregenix Membrane Microstructure NIA
porosity measurements (=tact angle measurements 1(10831 Representative samples of an embodiment of the membrane did not degrade after washing with water or ethanol. By contrast, a sample of a melt-blown membrane showed a significant decrease in filtration efficiency after washing with ethanol.

100841 A comparison between a=representative sample of an embodiment of the disclosed nanotibrous polymer membrane and a typical melt-blown membranc is shown in Table 2.

Parameter Melt-Blown Membrane Nanotiber Membrane clws,:,!(g,zra) 3 0.8 f jbj Diameter (pm) 100.
pore Si4e (.?
0,05 r iittatim Etticioncy (") PostrWashing Filtration Efficiency kripor OVVTR) 42 Wktt-; Cooiac:

CyiocomptibUity i 105 [00851 The filtration efficiency and observed pressure drop for various membrane samples is shown in Table 3.

Sample No. Flow Rate (L/min) Filtration Eiftleiency (%) Pressure Drop (mm wg) QP4i7 I85f 9730 13.8 QF-104 85 99.58 20.8 QI -i 0 85: : : 9902 18.7 Q1408 85 99.49 18.9 =MKEt)11: momm moõiimmõmaimmom 98;1:i7. 3.0 1V1X1011 32 98.10 4.6 MXF011 98.46 8.8 M.X.F011 80 97.16 11.8 K4XA/11: !100 97.05 MX F012 20 98.57 7,9 M.XF012 60 97.65 8.9 :
N4X POI 2 80 97.89 M X F012 100 98.18 16.6 MX1F.013 20 9,5.61 2.4 WIXF013 32 96.22 4.0 MX F01.3 60 95.98 8.6 MX F01:1 80 97.62 11.8 NIXF013 1:(X1 96.99 15.6 100861 FIGs. 6-12 show test results for filtration efficiency, flammability, and antiviral and antimicrobial properties for representative samples of an embodiment of the disclosed nanofibrous polymer membrane.
(0087] FIG. 13 shows how filtration efficiency is affected by the flow rate of aerosols through the membrane.
100881 FIG. 14 shows how the pressure drop across the membrane, which is a measure of breathability of the membrane, is affected by the flow rate of aerosols through the membrane.

100891 The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention disclosed herein.
Although the various inventive aspects are disclosed in the context of one or more illustrated embodiments, implementations, and examples, it Should be understood by those skilled in the art. that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof.
It should he also understood that the scope of this disclosure includes the various combinations or sub-combinations of the specific features and aspects of the embodiments disclosed hereinõ such that the various features, modes of implementation, and aspects of the disclosed subject matter may be combined with or substituted for one another.
The generic principles defined herein may be applied to other embodiments without departing from the -spirit or scope of the disclosure. Thus, the present disclosure is not intended to he limited to the embodiments shown herein but is to be accorded the widest. scope consistent with the principles and novel features disclosed herein.
100901 All references cited are hereby expressly incorporated herein by reference.

Claims

PCT/US2021/025285What is claimed is:

1.
electrospun polymer nanolibrous membrane having- a high filtration efficiency comprising polyvinylidene fluoride, one or more Tecophilierm thermoplastic polyurethanes, or a blend of polyvinylidene fluoride and one or more Tecophilierm thermoplastic polyurethanes, wherein the membrane is treated with one or more anti-pathogenic agents.
).

The membrane of Claim 1, wherein the one or more anti-pathogenic agents comprise an antiviral agent..

3. The menibrane of Claim 2, wherein the antiviral agent is selected from the group consisting of graphene, nanoparticles, nanocoraposites, multivalent metallic ions, and extracts from natural products.

4. The membrane of Claim 2, wherein the antiviral agena is coated on the surface of the membrane.

5. The menibrane of Claim 3, wherein the antiviral agent is selected from the group consisting of silver nanoparticles and zine nanoparticles.

6. The membrane of Claim 3, wherein the antiviral agent comprises a silver-doped titanium dioxide nanomaterial.

7. The membrane of Claim 3, wherein the antiviral agent comprises multivalent Cu2+ or Zn2-'. cations.

8. The membrane of Claim 3, wherein the antiviral agent cmnprises a licorice extract.

9. The membrane of Claim 1, whaein. one or more metal-organic frameworks are impregnated into the membrane.

10. The membrane of Claim S. wherein the one or more metal-organic frameworks comprise a :zirconium metal-organic framework.

11. The membrane of Claim 1, wherein the membrane is electrospun -from a polyiner solution that iacludes a surfactant.

12. The membrane of Claim 11, wherein the surfactant is selected from the eroup consisting of cetrimonium 'bromide (CTA13), lauramidopropyl betaine (1.AP13), and alpha olefin sulfonate (AOS).

13. The membrane of Claiin 1, wherein the membrane is electrospun from a polymer solution that includes a. salt.

14. The membrane of Claim 13, whemin the salt is sekcted from the group consisting of alkali metal halides.

15. The membrane of Claim. 2, wherein the .membrane comprises multiple integrated layers with distinguiShable microstructure characteristics.

16. The membrane of Claim 15, wherein the membrane is cxonposed of three layers ineluding a first and third layer having equal pore size separated by a second layer having a different pore size.

17. The membrane of Claim 16, wherein the first and third layers have a larger pore size and the second layer has a smaller pore size.

1 g. The membrane of claim 15, wherein the membrane is composed of three layers with three different pore sizes.

19. The membrane of Claim 17, wherein the mechanical integrity and binding forces between layers of the metnbrane is enhanced by electrospraying short fibers prior to electrospinning a subsequent layer of the membrane or by ekctrospinning wet fibers by decreasing the screen distance to generate a "tacky surface" prior to electrospitming a subsequent. layer of the membrane.

20. The membrane of Claim 15, wherein. the membrane is formed by winding a textile material roll comprising a textile material from a first side to a second side and then perfbrming the following steps in order:
a. electrospinning one or more first nanofi her layers on the first 'side of the textile material at a first winding speed;
b. flipping the textile material roll; and c. electrospinning one or more second nanoliber layers on the second side of the textile material at a second winding speed;
wherein the first winding speed is different from the second winding speed.

21. The mentbrane of Claim 15, wherein the membrane is formed by winding a textile material roll comprising a textile material from a first side to a second side and then performitig the following steps in order:

a. electrospinning one or more first nanofiber layers on the first .side of the textile material at a first winding speed; and b. electrospinning one or more second nanofiber layers on the first side of the textile material at a. second winding speed;
wherein the first winding speed is different from the second winding speed.

22. The membrane of Claim 15, wherein the membrane is formed by winding a textile material roll comprising a textile material frorn a first side to a seconi side and then performing the following steps in order:
a. electrospinning one or more first nanofiber layers on the first side of the textile material at a first winding speed;
b. elecirospinning one or more: second nanofiber layers on the first side of the textile material at a second winding speed;
c. flipping the textile rnaterial roll; and.
d. eleetrospinning one or more third tariofiber layers on the .second side of the textilematerial at a third. winding speed;
wherein the first winding speed is different from the second winding speed.

23. An electrospun polymer nanofibrous membrane having a high filtration efficiency comprisine polyvinylidene fluoride, one or more Tecophilier"
thermoplastic polyurethanes, or a blend of polyvinylidene fluoride and one or more Tecophilicrm theimoplastic polyurethanes, 'wherein one or moroanti-pathogenic agents is impregnated into the membrane.

/4. The membrane of Clairn 23, wherein one or rnore metal-organic frameworks are impregnated into the membrane.

25. The membrane of Claim 24, wherein the one or more metal-organic frameworks comprise a zirconium metal-organic frarnework.

26. The membrtme of Claim 23, wherein the Membrane is electrospun from a polymer solution that includes a surfactant.

27. :The membrane of Claim 26, wherein the surfactant is selected from the gronp consisting of cetrimonium bromide (CTAB), lauramidopropyl betaine (LAM), and alpha olefin sulfenate (MIS).

28. 'Ile -membrane of Claim 23,- wherein the membrane is efeetrospun from a polymer s.ohltion that includes:4 salt.

29. T11.0 meinbrane of Claim 28, wherein the salt is SeLeeted -from -the group -Nmsisting of alkali metal halides.

30. The _membrane of Claim 23, Wherein the inembrane 6)'mprik:s multiple inteqated layers with distinguishable illicrostructure Characteristics.

31. The membrane of Claim 30, wherein the membrane is com.posed of three layers including a first and. third layer having egtml pore size separated by -a wood layer 'having a different pore $ize.

32. The- membrane of claitrt 31., wherein the first and third layers have,a.hirger pore size. -and the seeond layer has a. 5aller pore:size:

33.
.The Menibrane of Claim wherein the membrane is. ermnposed of three layers with three different pore sizes.

34. The n)ernbrane of Claim 32, -sxtherein the 1110(:;hanieal. integrity and binding:
forces between layers of the nierribrane is enhanced by electaX=frs.prayine short .fibers-prior to eleetrospinning a -subsequent layer (If the .membrane or by eleetrospinniug wet fibers by decreasffig the screen di-Stance to generate a "tacky surface' prior to .electrospitnling a sOsequeur layer cf the membrane,.

35. An electrospun polymer natipfibrots inembrane 'having a high filtra0on efficiency compiising polyvinylidene fluoride, one or MOM Tecophillemi thermoplastic -pollytuethanes, or a blend of .polyvitt54idene fluoride and one or more Tecophilierm thermoplastic polyurethanes, wherein one or more tnetal-organie frameworks.
is. impregnated into the membrane.

36. The me.mbrane of Claim 22, -wherein the one or more metal-organic fminework.s comprise: a zirconium metal-organic framework.