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WO2025169010A1 - Articles transparents et masques faciaux et traitements associés - Google Patents

Articles transparents et masques faciaux et traitements associés

Info

Publication number
WO2025169010A1
WO2025169010A1 PCT/IB2025/000038 IB2025000038W WO2025169010A1 WO 2025169010 A1 WO2025169010 A1 WO 2025169010A1 IB 2025000038 W IB2025000038 W IB 2025000038W WO 2025169010 A1 WO2025169010 A1 WO 2025169010A1
Authority
WO
WIPO (PCT)
Prior art keywords
equal
less
layer
face mask
transparent face
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/IB2025/000038
Other languages
English (en)
Other versions
WO2025169010A8 (fr
Inventor
Hosseinali SAFAVIEH
Zahra Abdali
Milike GUZUTOK
Tien Nguyen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Plasmagear Inc
Original Assignee
Plasmagear Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Plasmagear Inc filed Critical Plasmagear Inc
Publication of WO2025169010A1 publication Critical patent/WO2025169010A1/fr
Publication of WO2025169010A8 publication Critical patent/WO2025169010A8/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1607—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
    • B01D39/1623—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
    • A—HUMAN NECESSITIES
    • A41—WEARING APPAREL
    • A41D—OUTERWEAR; PROTECTIVE GARMENTS; ACCESSORIES
    • A41D13/00—Professional, industrial or sporting protective garments, e.g. surgeons' gowns or garments protecting against blows or punches
    • A41D13/05—Professional, industrial or sporting protective garments, e.g. surgeons' gowns or garments protecting against blows or punches protecting only a particular body part
    • A41D13/11—Protective face masks, e.g. for surgical use, or for use in foul atmospheres
    • A41D13/1107—Protective face masks, e.g. for surgical use, or for use in foul atmospheres characterised by their shape
    • A41D13/1115—Protective face masks, e.g. for surgical use, or for use in foul atmospheres characterised by their shape with a horizontal pleated pocket
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/56—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with multiple filtering elements, characterised by their mutual disposition
    • B01D46/62—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with multiple filtering elements, characterised by their mutual disposition connected in series
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/02—Layered products comprising a layer of synthetic resin in the form of fibres or filaments
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/02—Types of fibres, filaments or particles, self-supporting or supported materials
    • B01D2239/025—Types of fibres, filaments or particles, self-supporting or supported materials comprising nanofibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/04—Additives and treatments of the filtering material
    • B01D2239/0414—Surface modifiers, e.g. comprising ion exchange groups
    • B01D2239/0428—Rendering the filter material hydrophobic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/0604—Arrangement of the fibres in the filtering material
    • B01D2239/0631—Electro-spun
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/065—More than one layer present in the filtering material
    • B01D2239/0654—Support layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/12—Special parameters characterising the filtering material
    • B01D2239/1233—Fibre diameter

Definitions

  • Transparent face masks, and associated treatments are generally provided.
  • the transparent face masks provided herein may have a number of advantages, including improved visibility of a wearer’s facial expressions, an improved ability to repel external fluids, an improved resistance to absorption of external fluids, and reduced damping of sound through the face mask.
  • Associated treatment methods which can, in some embodiments, contribute to one or more of these benefits, are also provided.
  • the subject matter of the present disclosure involves, in some cases, interrelated products, alternative solutions to a particular problem, and/or a plurality of different uses of one or more systems and/or articles.
  • FIGS. 1A-1C present schematic, cross-sectional illustrations of face masks, according to some embodiments.
  • FIG. 3 provides a schematic, cross-sectional illustration of a method of forming a face mask comprising nanostructures, according to some embodiments
  • FIG. 4 provides a schematic, cross-sectional illustration of a method of forming a face mask comprising nanostructures, according to some embodiments
  • FIG. 5 presents the attenuation of sound by various face masks, according to some embodiments.
  • FIG. 7 presents a photograph of a non-limiting two-pleated mask, contoured around a sculpted head, according to some embodiments
  • FIG. 8 presents a photograph of a non-limiting pleat-roller, according to some embodiments.
  • FIG. 9 presents dimensions of a non-limiting exemplary face mask having a design configuration according to the schematic illustration of FIG. 6A.
  • Transparent face masks represent a significant improvement in conventional face mask technology. However, improvements in transparency are often associated with significant reductions in filter-quality. Transparent face masks with high filtration efficiency are generally desired.
  • the present disclosure is directed, in various aspects, towards transparent face masks with good mechanical and filtration properties.
  • the transparent face masks described herein possess hydrophobic and/or hydrophilic surfaces that can improve the comfort level of the masks and/or improve their safety.
  • the disclosure is directed towards a face mask.
  • the face mask may comprise one or more layers.
  • layer generally refers to an arrangement of material that, when the material is laid flat, has a thickness dimension, a depth dimension that is perpendicular to the thickness dimension, and a width dimension that is perpendicular to both the thickness dimension and the depth dimension, where the lengths of each of the depth dimension and the width dimension are at least 3 times the length of the thickness dimension.
  • the length of the depth dimension of the layer is at least 5 times, at least 10 times, at least 25 times, at least 50 times, at least 100 times, at least 500 times, or at least 1000 times the length of the thickness dimension of the layer.
  • the length of the width dimension of the layer is at least 5 times, at least 10 times, at least 25 times, at least 50 times, at least 100 times, at least 500 times, or at least 1000 times the length of the thickness dimension of the layer.
  • the width and depth dimensions of a layer define its major surfaces.
  • a face mask may comprise any appropriate number and configuration of layers.
  • the face mask comprises a first layer and a second layer adjacent to the first layer.
  • the second layer is a filtration layer of the face mask, which is configured to filter air passing through the face mask.
  • the first layer may be a support layer that is configured to provide mechanical support to the filtration layer (e.g., the second layer).
  • the face mask further comprises a fourth layer (which may be, for example, another filtration layer).
  • the fourth layer may be disposed between the first layer and the third layer.
  • the fourth layer e.g., the filtration layer
  • FIG. IB presents such an embodiment, providing a cross-sectional, schematic illustration of face mask 101 comprising first layer 103, second layer 105, third layer 107, and fourth layer 109, where fourth layer 109 is disposed between first layer 103 and third layer 107.
  • Such a “fourlayered” configuration of a face mask may be particularly advantageous for retaining transparency while reducing permeability to aqueous fluids such as blood.
  • the use of two or more filtration layers may allow the two or more filtration layers to each be thinner, resulting in a face mask with improved safety and filtration properties for a given transparency.
  • face masks comprising two or more filtration layers may be more difficult or costly to produce, meaning that face masks with only a single filtration layer may also be advantageous, depending on the embodiment.
  • a layer (e.g., a first layer, a second layer, a third layer, or a fourth layer) is or comprises a fiber web (a layer comprising a fiber web is interchangeably referred to as a “fiber web layer,” herein).
  • a layer may comprise a woven fiber web or a nonwoven fiber web.
  • the fiber web comprises a plurality of fibers. A plurality of fibers may be entangled (e.g., by weaving). The fibers may be continuous fibers or non-continuous fibers.
  • a face mask comprises a plurality of nanostructures deposited at a hydrophobic surface of a layer, as discussed below.
  • the layer (and/or coating) and a plurality of nanostructures may have different compositions, in some embodiments.
  • the nanostructures may be formed from a relatively more hydrophobic material than a layer, or a coating on layer, in some embodiments.
  • the disclosure is directed towards a transparent face mask.
  • the light incident upon a conventional face mask is typically scattered by one or more layers of the conventional face mask, significantly limiting transmission of light through the face mask.
  • the present disclosure has recognized that, without wishing to be bound by any particular theory, a high proportion of the scattered light is scattered from a filtration layer (e.g., a second layer, a fourth layer) of the face mask, and that this scattering could be limited by using a filtration layer (e.g., a second layer, a fourth layer) comprising fibers having a relatively small diameter.
  • fibers having an average diameter smaller than a wavelength of visible light may have a reduced ability to scatter visible light, relative to wider fibers.
  • the present disclosure is directed towards a face mask comprising a filtration layer (e.g., a second layer, a fourth layer) having a relatively small average fiber diameter, as discussed below.
  • a face mask described herein may have any of a variety of appropriate optical transparencies.
  • a face mask has an optical transparency of greater than or equal to 40%, greater than or equal to 45%, greater than or equal to 48%, greater than or equal to 50%, greater than or equal to 52%, greater than or equal to 55%, greater than or equal to 58%, greater than or equal to 60%, greater than or equal to 62%, greater than or equal to 65%, greater than or equal to 68%, greater than or equal to 70%, greater than or equal to 72%, greater than or equal to 75%, greater than or equal to 75%, or greater than or equal to 80% for a wavelength of light.
  • a face mask has an optical transparency of less than or equal to 80%, less than or equal to 78%, less than or equal to 75%, less than or equal to 72%, less than or equal to 70%, less than or equal to 68%, less than or equal to 65%, less than or equal to 62%, or less than or equal to 60% for a wavelength of light. Combinations of these ranges are also possible (e.g., greater than or equal to 40% and less than or equal to 80%, greater than or equal to 50% and less than or equal to 70%, or greater than or equal to 60% and less than or equal to 65%). Other ranges are also possible.
  • a face mask has a transparency in an aforementioned range for light having a wavelength of greater than or equal to 190 nm, greater than or equal to 210 nm, greater than or equal to 240 nm, greater than or equal to 270 nm, greater than or equal to 300 nm, greater than or equal to 330 nm, greater than or equal to 360 nm, greater than or equal to 390 nm, greater than or equal to 420 nm, greater than or equal to 450 nm, greater than or equal to 480 nm, greater than or equal to 510 nm, greater than or equal to 540 nm, greater than or equal to 570 nm, greater than or equal to 600 nm, greater than or equal to 630 nm, greater than or equal to 660 nm, greater than or equal to 690 nm, or greater than or equal to 720 nm
  • a face mask has a transparency in an aforementioned range for light having a wavelength of less than or equal to 810 nm, less than or equal to 780 nm, less than or equal to 750 nm, less than or equal to 720 nm, less than or equal to 690 nm, less than or equal to 660 nm, less than or equal to 630 nm, less than or equal to 600 nm, less than or equal to 570 nm, less than or equal to 540 nm, less than or equal to 510 nm, less than or equal to 480 nm, less than or equal to 450 nm, less than or equal to 420 nm, less than or equal to 390 nm, or less than or equal to 360 nm. Combinations of these ranges are also possible (e.g., greater than or equal to 190 nm and less than or equal to 810 nm). Other ranges are also possible.
  • a transparency of greater than or equal to 50%, greater than or equal to 60%, greater than or equal to 70%, or greater than or equal to 80% may be achieved for a wavelength of greater than or equal to 300 nm and less than or equal to 720 nm.
  • a layer such as a filtration layer may comprise a plurality of fibers.
  • at least some of (e.g., all of) a plurality of fibers of a filtration layer are polymeric fibers.
  • Polymeric fibers of a filtration layer may comprise PET, PLA, PLGA, PVDF, PHA, PHB, TPU, cellulose, poly(ethylene-co-vinyl acetate), polyurethane, polyvinylchloride, or combinations thereof.
  • the polymeric fibers comprise a PVDF.
  • the PVDF may be included in any of a variety of appropriate proportions versus the total weight of the polymeric fibers.
  • the polymeric fibers comprise PVDF in an amount of greater than or equal to 75 wt%, greater than or equal to 80 wt%, greater than or equal to 85 wt%, greater than or equal to 90 wt%, greater than or equal to 95 wt%, or more.
  • the polymeric fibers comprise PVDF in an amount of less than or equal to 100 wt%, less than or equal to 95 wt%, less than or equal to 90 wt%, or less.
  • the polymer composition comprises PVDF in an amount of greater than or equal to 75 wt% and less than or equal to 100 wt% (e.g., greater than or equal to 80 wt% and less than or equal to 90 wt%).
  • PVDF in an amount of greater than or equal to 75 wt% and less than or equal to 100 wt% (e.g., greater than or equal to 80 wt% and less than or equal to 90 wt%).
  • Other amounts of PVDF inclusion in the polymeric fibers are also possible, as the disclosure is not so limited.
  • the polymeric fibers comprise a TPU.
  • the TPU may be included in any of a variety of appropriate proportions versus the total weight of the polymeric fibers.
  • the polymeric fibers comprise TPU in an amount of greater than or equal to 0 wt%, greater than or equal to 5 wt%, greater than or equal to 10 wt%, greater than or equal to 15 wt%, or more.
  • the polymeric fibers comprise TPU in an amount of less than or equal to 25 wt%, less than or equal to 20 wt%, less than or equal to 15 wt%, or less.
  • the polymer composition comprises TPU in an amount of greater than or equal to 0 wt% and less than or equal to 25 wt% (e.g., greater than or equal to 10 wt% and less than or equal to 20 wt%).
  • TPU in an amount of greater than or equal to 0 wt% and less than or equal to 25 wt% (e.g., greater than or equal to 10 wt% and less than or equal to 20 wt%).
  • Other amounts of TPU inclusion in the polymeric fibers are also possible, as the disclosure is not so limited.
  • polymeric fibers comprise PVDF in an amount greater than or equal to 80 wt% and less than or equal to 90 wt% versus the total weight of the polymeric fibers, and further comprises TPU in an amount greater than or equal to 10 wt% and less than or equal to 20 wt% versus the total weight of the polymeric fibers.
  • Such compositions may have advantageous properties for use in filtration layers.
  • the polymeric fibers are about 85 wt% PVDF and about 15 wt% TPU.
  • a plurality of fibers comprises a mixture of fibers with different compositions (e.g., a mixture of PLA fibers and PLGA fibers, or a mixture of cotton fibers and polymeric fibers). In some embodiments, a plurality of fibers comprises fibers with uniform compositions that are blends or copolymers of two or more polymers.
  • a filtration layer may be made from compostable materials (e.g., PLA, PLGA), according to some embodiments.
  • a filtration layer e.g., a second layer, a fourth layer
  • a filtration layer may be made from recyclable materials.
  • a filtration layer e.g., a second layer, a fourth layer
  • a vitrimer which may be collected and re-processed (e.g., by dissolution in in mild solvents such as N-methyl pyrrolidone or dimethyl formamide or aqueous solution) for reuse.
  • Exemplary vitrimers and/or other materials that may be used include, but are not limited to: epoxybased or vinyl-based vitrimers such as vanillin-based epoxy resins, vanillin-guaiacol resins (e.g., diglycidyl ether of bisphenol), and/or vitrimeric networks comprising guaiacol, eugenol, vanillic acid, isophoronediamine, epichlorohydrin, glycyrrhizic acid, soybean oil, poly(itaconate) elastomers, lignin-based vitrimers, polyimine-network based vitrimers, polybutadiene-based elastomers, succinic anhydride, glutaric anhydride, Methylhexahydrophthalic Anhydride (MHHPA), and/or phthalic anhydride .
  • epoxybased or vinyl-based vitrimers such as vanillin-based epoxy resins, vanillin-guaiacol resins (e
  • a filtration layer (e.g., a second layer, a fourth layer) may be formed by electrospinning (e.g., melt electrospinning or solvent electrospinning), and thus may comprise electospun fibers having the material types, dimensions, and amount described herein for the filtration layer (e.g., second layer, a fourth layer).
  • the filtration layer e.g., second layer, fourth layer
  • the fibers of a filtration layer may have any of a variety of appropriate diameters. As discussed above, in some embodiments, the diameters of the fibers are relatively small, with the advantageous effect of improving mask transparency.
  • fibers make up less than or equal to 100 wt%, less than or equal to 95 wt%, less than or equal to 90 wt%, less than or equal to 85 wt%, less than or equal to 80 wt%, less than or equal to 75 wt%, less than or equal to 70 wt%, less than or equal to 65 wt%, less than or equal to 60 wt% of the filtration layer (e.g., the second layer, the fourth layer).
  • the filtration layer e.g., the second layer, the fourth layer.
  • a filtration layer (e.g., a second layer, a fourth layer) described herein may have any suitable elastic modulus.
  • a filtration layer (e.g., a second layer, a fourth layer) layer has an elastic modulus of greater than or equal to 20 kPa, greater than or equal to 40 kPa, greater than or equal to 60 kPa, greater than or equal to 80 kPa, greater than or equal to 100 kPa, greater than or equal to 200 kPa, greater than or equal to 500 kPa, greater than or equal to 1 MPa, greater than or equal to 2 MPa, greater than or equal to 5 MPa, greater than or equal to 10 MPa, greater than or equal to 50 MPa, greater than or equal to 100 MPa, greater than or equal to 200 MPa, greater than or equal to 500 MPa, greater than or equal to 1 GPa, or greater than or equal to 2 GPa.
  • a filtration layer (e.g., a second layer, a fourth layer) has an elastic modulus of less than or equal to 5 GPa, less than or equal to 2 GPa, less than or equal to 1 GPa, less than or equal to 500 MPa, less than or equal to 200 MPa, less than or equal to 100 MPa, less than or equal to 50 MPa, less than or equal to 20 MPa, less than or equal to 10 MPa, less than or equal to 5 MPa, less than or equal to 2 MPa, less than or equal to 1 MPa, less than or equal to 500 kPa, less than or equal to 200 kPa, less than or equal to 100 kPa, less than or equal to 80 kPa, less than or equal to 60 kPa, or less than or equal to 40 kPa.
  • a support layer (e.g., a first layer, a third layer) may be made from compostable materials (e.g., PLA, PLGA), according to some embodiments.
  • a support layer may be configured to break down over a period of less than or equal to 12 months, less than or equal to 10 months, less than or equal to 8 months, or less than or equal to 6 months, when composted.
  • a support layer (e.g., a first layer, a third layer) may be made from recyclable materials.
  • a support layer e.g., a first layer, a third layer
  • comprises a vitrimer which may be collected and re-processed (e.g., by dissolution in an acid) for reuse.
  • the fibers of the support layer may have a larger average fiber diameter than those of the filtration layer (e.g., second layer, fourth layer).
  • a support layer (e.g., a first layer, a third layer) comprises fibers having a length of less than or equal to 20 cm, less than or equal to 19 cm, less than or equal to 18 cm, less than or equal to 17 cm, less than or equal to 16 cm, less than or equal to 15 cm, less than or equal to 14 cm, less than or equal to 13 cm, less than or equal to 12 cm, less than or equal to 11 cm, less than or equal to 10 cm, less than or equal to 9 cm, less than or equal to 8 cm, less than or equal to 7 cm, less than or equal to 6 cm, less than or equal to 5 cm, less than or equal to 4 cm, less than or equal to 3 cm, less than or equal to 2 cm, less than or equal to 1 cm, or less than or equal to 0.5 cm.
  • Fibers may make up any of a variety of weight percentages of a support layer (e.g., a first layer, a third layer). In some embodiments, fibers make up greater than or equal to 0.1 wt%, greater than or equal to 0.25 wt%, greater than or equal to 0.5 wt%, greater than or equal to 1 wt%, greater than or equal to 2 wt%, greater than or equal to 5 wt%, greater than or equal to 8 wt%, greater than or equal to 10 wt%, greater than or equal to 12 wt%, greater than or equal to 15 wt%, greater than or equal to 18 wt%, greater than or equal to 20 wt%, greater than or equal to 25 wt%, greater than or equal to 30 wt%, greater than or equal to 35 wt%, greater than or equal to 40 wt%, greater than or equal to 45 wt%, greater than or equal to 50 wt%, greater than or equal to 55 wt
  • fibers make up less than or equal to 100 wt%, less than or equal to 95 wt%, less than or equal to 90 wt%, less than or equal to 85 wt%, less than or equal to 80 wt%, less than or equal to 75 wt%, less than or equal to 70 wt%, less than or equal to 65 wt%, less than or equal to 60 wt%, less than or equal to 55 wt%, less than or equal to 40 wt%, less than or equal to 35 wt%, less than or equal to 30 wt%, less than or equal to 25 wt%, less than or equal to 20 wt%, less than or equal to 18 wt%, less than or equal to 15 wt%, less than or equal to 12 wt%, less than or equal to 10 wt%, less than or equal to 8 wt%, or less than or equal to 5 wt% of the support layer (e.g., the first layer, the
  • Combinations of these ranges are also possible (e.g., greater than or equal to 0.1 wt% and less than or equal to 100 wt%, greater than or equal to 0.25 wt% and less than or equal to 25 wt%, or greater than or equal to 0.25 wt% and less than or equal to 5 wt%). Other ranges are also possible.
  • the support layer (e.g., the first layer, the third layer) may have any of a variety of appropriate specific surface areas.
  • a support layer (e.g., a first layer, a third layer) has a specific surface area of greater than or equal to 0.1 m 2 /g, greater than or equal to 0.2 m 2 /g, greater than or equal to 0.5 m 2 /g, greater than or equal to 0.8 m 2 /g, greater than or equal to 1 m 2 /g, greater than or equal to 1.2 m 2 /g, greater than or equal to 1.5 m 2 /g, greater than or equal to l.m 2 /g, greater than or equal to 2 m 2 /g, greater than or equal to 3 m 2 /g, or greater than or equal to 4 m 2 /g.
  • a support layer (e.g., a first layer, a third layer) has a specific surface area of less than or equal to 5 m 2 /g, less than or equal to 4 m 2 /g, less than or equal to 3 m 2 /g, less than or equal to 2 m 2 /g, less than or equal to 1.8 m 2 /g, less than or equal to 1.5 m 2 /g, less than or equal to 1.2 m 2 /g, less than or equal to 1 m 2 /g, less than or equal to 0.8 m 2 /g, less than or equal to 0.5 m 2 /g, or less than or equal to 0.2 m 2 /g.
  • a support layer e.g., a first layer, a third layer described herein may have any suitable elastic modulus.
  • a support layer (e.g., a first layer, a third layer) layer has an elastic modulus of greater than or equal to 30 kPa, greater than or equal to 40 kPa, greater than or equal to 60 kPa, greater than or equal to 80 kPa, greater than or equal to 100 kPa, greater than or equal to 200 kPa, greater than or equal to 500 kPa, greater than or equal to 1 MPa, greater than or equal to 2 MPa, greater than or equal to 5 MPa, greater than or equal to 10 MPa, greater than or equal to 50 MPa, greater than or equal to 100 MPa, greater than or equal to 200 MPa, greater than or equal to 500 MPa, greater than or equal to 1 GPa, greater than or equal to 2 GPa, greater than or equal to 2.5 GPa, greater than or equal to 3 GPa, greater than or equal to 3.5 GPa.
  • a face mask may, in some embodiments, comprise one or more separation layers.
  • a separation layer e.g., a fifth layer
  • a separation layer may be configured, according to some embodiments, such that it is disposed between and separates two other layers (e.g., a first layer, a second layer, a third layer, or a fourth layer) of the face mask.
  • a separation layer may be disposed between two filtration layers (e.g., between a second layer and a fourth layer) of a face mask.
  • 1C presents such an embodiment, providing a cross-sectional, schematic illustration of face mask 101 comprising first, support layer 103, second, filtration layer 105, third, support layer 107, fourth, filtration layer 109, and fifth, separation layer 111, where separation layer 111 is disposed between second, filtration layer 105 and fourth, filtration layer 109.
  • One or more separation layers may be used in a face mask, depending on the embodiment.
  • the use of the separation layer is advantageous for reducing wear on a filtration layer of a face mask.
  • the separation layer may separate a second, filtration layer from a fourth, filtration layer, such that the second layer and the fourth layer are less prone to damage from their friction against one another.
  • a layer such as a separation layer may comprise a plurality of fibers.
  • at least some of (e.g., all of) a plurality of fibers of a separation layer are polymeric fibers.
  • at least some of (e.g., all of) a plurality of fibers of a separation layer are polymeric fibers.
  • a plurality of fibers may comprise nylon, cotton, polyester, copolyamides, a polyaramid (e.g., poly(meta-aramid), commercially known as Nomex; poly (para-aramid), commercially known as Kevlar), PET, PLA, PLGA, PVDF, PHA, PHB, TPU, cellulose, poly(ethylene-co-vinyl acetate), polyurethane, polyvinylchloride, or combinations thereof.
  • a plurality of fibers comprises a mixture of fibers with different compositions (e.g., a mixture of Nomex fibers and cotton fibers, or a mixture of cotton fibers and polymeric fibers).
  • a plurality of fibers comprises fibers with uniform compositions that are blends or copolymers of two or more polymers.
  • a nylon separation layer has been observed to be advantageous for use as a separation layer.
  • a separation layer may be made from recyclable materials.
  • a separation layer e.g., a fifth layer
  • a separation layer comprises a fiber web.
  • a separation layer may comprise fibers in any of a variety of appropriate proportions of the separation layer.
  • a separation layer comprises fibers in a weight percentage of greater than or equal to 0.1 wt%, greater than or equal to 1 wt%, greater than or equal to 2 wt%, greater than or equal to 5 wt%, greater than or equal to 10 wt%, greater than or equal to 20 wt%, greater than or equal to 30 wt%, greater than or equal to 40 wt%, greater than or equal to 50 wt%, greater than or equal to 60 wt%, greater than or equal to 70 wt%, greater than or equal to 80 wt%, greater than or equal to 90 wt%, greater than or equal to 95 wt%, or greater than or equal to 98 wt%.
  • a separation layer may include fibers having any of a variety of appropriate diameters.
  • a separation layer includes fibers having an average diameter of greater than or equal to 1 micron, greater than or equal to 2 microns, greater than or equal to 5 microns, greater than or equal to 10 microns, greater than or equal to 15 microns, greater than or equal to 20 microns, greater than or equal to 25 microns, greater than or equal to 30 microns, greater than or equal to 35 microns, greater than or equal to 40 microns, greater than or equal to 45 microns, greater than or equal to 50 microns, greater than or equal to 55 microns, greater than or equal to 60 microns, greater than or equal to 65 microns, greater than or equal to 70 microns, greater than or equal to 75 microns, greater than or equal to 80 microns, greater than or equal to 85 microns, greater than or equal to 90 microns, or greater than or equal to 95 microns.
  • a separation layer includes fibers having an average diameter of less than or equal to 100 microns, less than or equal to 95 microns, less than or equal to 90 microns, less than or equal to 85 microns, less than or equal to 80 microns, less than or equal to 75 microns, less than or equal to 70 microns, less than or equal to 65 microns, less than or equal to 60 microns, less than or equal to 55 microns, less than or equal to 50 microns, less than or equal to 45 microns, less than or equal to 40 microns, less than or equal to 35 microns, less than or equal to 30 microns, less than or equal to 25 microns, less than or equal to 20 microns, less than or equal to 15 microns, less than or equal to 10 microns, or less than or equal to 5 microns.
  • Combinations of these ranges are also possible (e.g., greater than or equal to 1 microns and less than or equal to 100 microns, greater than or equal to 5 microns and less than or equal to 20 microns, or greater than or equal to 10 microns and less than or equal to 15 microns). Other ranges are also possible.
  • a separation layer may include fibers having any of a variety of appropriate lengths.
  • a separation layer includes fibers having an average length of greater than or equal to 2.0 cm, greater than or equal to 2.5 cm, greater than or equal to 3.0 cm, greater than or equal to 3.5 cm, greater than or equal to 4.0 cm, greater than or equal to 4.5 cm, greater than or equal to 5.0 cm, greater than or equal to 5.5 cm, greater than or equal to 6.0 cm, greater than or equal to 6.5 cm, greater than or equal to 7.0 cm, greater than or equal to 7.5 cm, greater than or equal to 8.0 cm, greater than or equal to 8.5 cm, greater than or equal to 9.0 cm, greater than or equal to 9.5 cm, greater than or equal to 10 cm, greater than or equal to 10.5 cm, greater than or equal to 11.0 cm, greater than or equal to 11.5 cm, greater than or equal to 12 cm, greater than or equal to
  • a separation layer includes fibers having an average length of less than or equal to 20.0 cm, less than or equal to
  • the mask may include one or more additional layers, in addition to support layers, filtration layers, and/or separation layers, as the disclosure is not so limited.
  • a face mask may comprise one or more layers of an adhesive, depending on the embodiment.
  • One or more surfaces of a face mask may be treated, according to some embodiments, in order to control the interaction of the face mask with a fluid.
  • the surface may be treated by depositing a plurality of nanostructures, and/or a coating layer on the surface, as described in greater detail below.
  • Such treatments can present significant advantages, depending on the embodiment.
  • face masks are commonly used in medical contexts, where potentially infectious fluids such as blood might contact an external surface of a face mask.
  • internal and/or external surfaces of the face mask may be treated to make them hydrophobic or hydrophilic.
  • a face mask may include both a hydrophobic external surface (e.g., outermost surface with respect to a user wearing the face mask) and a hydrophilic internal surface (e.g., inner most surface with respect to a user wearing the face mask), as described herein.
  • a hydrophobic external surface e.g., outermost surface with respect to a user wearing the face mask
  • a hydrophilic internal surface e.g., inner most surface with respect to a user wearing the face mask
  • face masks comprising hydrophobic and/or oleophobic surfaces, and associated methods, are described.
  • the methods herein are directed towards the fabrication of non-fluorinated hydrophobic and/or oleophobic surfaces on face masks, which may provide a number of environmental and performance-related advantages.
  • a method of forming a face mask is generally described.
  • a method may comprise forming one or more nanostructures at a surface of a layer (e.g., a support layer, such as a first layer or a third layer) such that the surface comprises the nanostructures.
  • the layer may be a layer of a face mask, or a layer suitable for subsequent use in a face mask.
  • FIG. 2A provides a schematic cross-sectional illustration of a nonlimiting flat layer 201 in contact with a water droplet 203 to create a contact angle 205 defined by a direction 207 at which the surface of water droplet 203 contacts layer 201.
  • the “contact angle” of a particular liquid phase (e.g., water) on a layer is measured through the bulk of the liquid phase. Generally, higher water contact angles are associated with more hydrophobic and/or oleophobic interfaces.
  • An advantage of some methods described herein is the formation of such nanostructures on the surface of a layer (e.g., a layer suitable for use in a face mask, such as a first layer or a third layer), which has been difficult to achieve.
  • a layer e.g., a layer suitable for use in a face mask, such as a first layer or a third layer
  • FIG. 2B shows nanostructures that are regularly sized and spaced, in other embodiments other shapes, sizes, and spacing of nanostructures are possible, as described in more detail herein.
  • heterogeneous nanostructures are formed (e.g., nanostructures having different heights, widths, diameters, and/or lengths, etc.).
  • a method comprises forming nanostructures (e.g., at a surface of a face mask, or at a surface of a layer, such as a support layer that may be a assembled into a first layer or a third layer of a face mask) using a plasma.
  • a method may comprise a first step of exposing a layer to a plasma.
  • FIG. 3 presents a schematic illustration of a nonlimiting example of such a method.
  • a layer 301 is exposed to a first plasma 320 to produce a plurality of nanostructures 307 at a surface of layer 301.
  • the plasma may be used to chemically vapor deposit nanostructures at the surface of a layer (e.g., at a surface of a support layer that may be a first layer and/or a third layer of a face mask).
  • the nanostructures are formed by an island growth mechanism.
  • the resulting nanostructures may be discrete entities that are separated and isolated from other nanostructures (e.g., the nanostructures are unconnected from each other and/or are separated from each other by a material that is different from the material forming the nanostructures).
  • nanostructures are formed using a top down approach that does not involve etching of a layer. In other words, the process lacks an etching step.
  • the method shown in FIG. 3 may be used to form heterogeneous nanostructures (e.g., nanostructures having different heights, widths, diameters, and/or lengths, etc.). In some embodiments, the method may be used to form homogeneous nanostructures. In other embodiments, the method may be used to form heterogenous nanostructures.
  • heterogeneous nanostructures e.g., nanostructures having different heights, widths, diameters, and/or lengths, etc.
  • the method may be used to form homogeneous nanostructures. In other embodiments, the method may be used to form heterogenous nanostructures.
  • a plurality of nanostructures may be formed at a surface of a layer (e.g., at a surface of a support layer that may be a first layer or a third layer) by exposing a surface of the layer to a plasma comprising a monomer.
  • exposing a surface of a layer to a plasma that comprises a monomer produces a face mask with a plurality of nanostructures at a surface of the layer.
  • a plurality of nanostructures may comprise a polymer (e.g., a polymerized monomer of the monomers present in the plasma).
  • a plasma may comprise a monomer.
  • a plasma may comprise an organic monomer, such as a hydrocarbon monomer.
  • a method comprises polymerizing monomers (e.g., hydrocarbon monomers) from a plasma to form a polymer nanostructure during plasma deposition.
  • a nanostructure formed by plasma deposition may be or comprise a polymerized form of a monomer in the plasma.
  • an organic monomer such as a hydrocarbon monomer may be polymerized by the plasma to produce an organic polymer such as a hydrocarbon polymer.
  • a plasma comprises an organic monomer such as ethylene, butadiene acetylene, methane, methanol, or ethanol.
  • the organic monomer may be a hydrocarbon monomer (e.g., ethylene, butadiene, acetylene, or methane).
  • plasma deposition of organic monomers forms an organic polymer.
  • a plasma suitable for depositing a nanostructure may be used in a chamber having any of a variety of suitable pressures.
  • a plurality of nanostructures are plasma-deposited in a chamber having a pressure of greater than or equal to 0.01 Pa, greater than or equal to 0.02 Pa, greater than or equal to 0.05 Pa, greater than or equal to 0.1 Pa, greater than or equal to 0.2 Pa, greater than or equal to 0.5 Pa, greater than or equal to 1 Pa, greater than or equal to 2 Pa, greater than or equal to 5 Pa, or greater than or equal to 10 Pa.
  • a plasma for depositing a nanostructure has a power of less than or equal to 1300 W, less than or equal to 1280 W, less than or equal to 1250 W, less than or equal to 1220 W, less than or equal to 1200 W, less than or equal to 1180 W, less than or equal to 1150 W, less than or equal to 1120 W, less than or equal to 1100 W, less than or equal to 1080 W, less than or equal to 1050 W, less than or equal to 1020 W, less than or equal to 1000 W, less than or equal to 980 W, less than or equal to 950 W, less than or equal to 920 W, less than or equal to 900 W, less than or equal to 880 W, less than or equal to 850 W, or less than or equal to 820 W. Combinations of these ranges are also possible (e.g., greater than or equal to 800 W and less than or equal to 1300 W or greater than or equal to 900 and less than or equal to 1250 W). Other ranges are also possible (e.g
  • a method may comprise depositing a coating layer at a surface of a layer (e.g., a support layer that may be a first layer or a third layer) such that the surface comprises the coating layer.
  • the coating layer may be deposited on top of a plurality of nanostructures (e.g., on top of a plurality of nanowires at a surface of a face mask or layer, such as a support layer that may be a first layer or third layer).
  • a method step 352 comprises depositing a coating layer 313 on top of nanostructures 307.
  • a coating layer formed on top of a plurality of nanostructures may retain a texture of the plurality of nanostructures. For example, as shown in FIG.
  • coating layer 313 retains a texture that includes hills 397 (e.g., the coating layer is higher above nanostructures 307) and valleys 399 (e.g., the coating layer is lower elsewhere).
  • a coating layer having such undulations (e.g., hills and valleys, protrusions and indentations) positioned on top of a plurality of nanostructures may have increased oleophobicity and/or hydrophobicity relative to an analogous flat coating layer having an identical composition (e.g., absent the nanostructures, all other factors being equal), since the coating layer’s texture may create the same increase in contact angle described above with reference to FIG. 2B.
  • the increase in oleophobicity and/or hydrophobicity and/or contact angle resulting from the presence of the coating layer over the nanostructures may be attributable to the presence of an ambient gas between the nanostructures.
  • a coating layer may be deposited at a surface of a layer (e.g., at a surface of a support layer that may be a first layer or a third layer) by any of a variety of appropriate methods.
  • a coating layer is deposited using plasma.
  • coating layer 313 is deposited using a plasma 322.
  • a plasma used to deposit a coating layer may comprise a monomer such as an organic monomer and/or a silicon-based monomer (e.g., a silane or a siloxane). Appropriate types of organic and silicon-based monomers are discussed above, in the context of plasmas used to form nanostructures — any monomer listed there may be used for coating layer formation.
  • a plasma used for coating layer deposition comprises a reactive species.
  • a plasma may comprise a reactive species such as such as oxygen, argon, helium, neon, krypton, xenon, or combination thereof.
  • a reactive species may etch a coating layer as the coating layer is deposited (as discussed in greater detail below).
  • a reactive species reacts with monomers of a plasma prior to deposition of the monomers onto a coating layer. Reaction of the monomers with the reactive species may result in the formation of radicalized monomers of the plasma. Radicalized monomers may deposit on the coating layers at different rates, and may cause changes to properties of a deposited coating layer.
  • a plasma suitable for depositing a coating layer (e.g., plasma 322 of FIG. 3) described herein may be used in a chamber having any of a variety of suitable pressures.
  • a coating layer is plasma-deposited in a chamber having a pressure of greater than or equal to 5 Pa, greater than or equal to 10 Pa, greater than or equal to 15 Pa, greater than or equal to 20 Pa, greater than or equal to 25 Pa, greater than or equal to 30 Pa, greater than or equal to 35 Pa, greater than or equal to 40 Pa, greater than or equal to 45 Pa, greater than or equal to 50 Pa, greater than or equal to 55 Pa, greater than or equal to 60 Pa, greater than or equal to 65 Pa, greater than or equal to 70 Pa, greater than or equal to 75 Pa, greater than or equal to 80 Pa, or greater than or equal to 85 Pa.
  • a coating layer is plasma-deposited in a chamber having a pressure of less than or equal to 90 Pa, less than or equal to 85 Pa, less than or equal to 80 Pa, less than or equal to 75 Pa, less than or equal to 70 Pa, less than or equal to 65 Pa, less than or equal to 60 Pa, less than or equal to 55 Pa, less than or equal to 50 Pa, less than or equal to 45 Pa, less than or equal to 40 Pa, less than or equal to 35 Pa, less than or equal to 30 Pa, less than or equal to 25 Pa, less than or equal to 20 Pa, less than or equal to 15 Pa, or less than or equal to 10 Pa.
  • Ranges are also possible (e.g., greater than or equal to 5 Pa and less than or equal to 90 Pa, greater than or equal to 20 Pa and less than or equal to 80 Pa, greater than or equal to 40 Pa and less than or equal to 60 Pa, or greater than or equal to 10 Pa and less than or equal to 40 Pa).
  • the aforementioned ranges may refer to plasmas comprising any of the types of monomers described above, and that different pressures may be suitable for deposition of different coating layers, depending on the embodiment. Other ranges are also possible.
  • a plasma for depositing a coating layer may have any of a variety of suitable powers.
  • a plasma for depositing a coating layer has a power of greater than or equal to 500 W, greater than or equal to 550 W, greater than or equal to 600 W, greater than or equal to 650 W, greater than or equal to 700 W, greater than or equal to 750 W, greater than or equal to 800 W, greater than or equal to 850 W, greater than or equal to 900 W, greater than or equal to 950 W, greater than or equal to 1000 W, greater than or equal to 1050 W, greater than or equal to 1100 W, greater than or equal to 1150 W, greater than or equal to 1200 W, greater than or equal to 1250 W, greater than or equal to 1300 W, greater than or equal to 1350 W, greater than or equal to 1400 W, or greater than or equal to 1450 W.
  • a plasma for depositing a coating layer has a power of less than or equal to 1500 W, less than or equal to 1450 W, less than or equal to 1400 W, less than or equal to 1350 W, less than or equal to 1300 W, less than or equal to 1250 W, less than or equal to 1200 W, less than or equal to 1150 W, less than or equal to 1100 W, less than or equal to 1050 W, less than or equal to 1000 W, less than or equal to 950 W, less than or equal to 900 W, less than or equal to 850 W, less than or equal to 800 W, less than or equal to 750 W, less than or equal to 700 W, less than or equal to 650 W, less than or equal to 600 W, or less than or equal to 550 W.
  • a coating layer positioned on top of on top of a plurality of nanostructures at a surface of a layer may have any of a variety of appropriate compositions.
  • a coating layer formed on top of a plurality of nanostructures is or comprises a polymerized silane.
  • a coating layer formed on top of a plurality of nanostructures is or comprises a polymerized siloxane.
  • a face mask comprises a coating layer that covers less than or equal to 100%, less than or equal to 99%, less than or equal to 95%, less than or equal to 90%, less than or equal to 75%, or less than or equal to 50% of a plurality of nanostructures positioned on a surface of a coating layer. Combinations of these ranges are also possible (e.g., greater than or equal to 1% and less than or equal to 100%, greater than or equal to 25% and less than or equal to 100%, or greater than or equal to 50% and less than or equal to 100%). Other ranges are also possible.
  • a face mask described herein may comprise a coating layer covering a plurality of nanostructures and having any of a variety of suitable thicknesses.
  • Combinations of these ranges are also possible (e.g., greater than or equal to 7 nm and less than or equal to 10000 nm, greater than or equal to 20 nm and less than or equal to 50 nm, greater than or equal to 20 nm and less than or equal to 40 nm, greater than or equal to 100 nm and less than or equal to 200 nm, or greater than or equal to 30 nm and less than or equal to 50 nm). Other ranges are also possible. According to another aspect, a method of forming a face mask involving etching is provided.
  • a coating layer suitable for etching may be formed by one or more methods described above.
  • coating layer 433 may be formed by exposing coating layer 401 to a plasma 420 comprising a monomer (e.g., an organic monomer) at an appropriate pressure and power to form a uniform coating layer, as described above.
  • method comprises forming a coating layer that comprises or consists of an organic polymer on top of a coating layer.
  • Coating layer 433 may comprise a polymer.
  • coating layer 433 comprises an organic polymer polymerized from an organic monomer in plasma 420, according to some embodiments.
  • a coating layer is etched to form an etched coating layer.
  • An etched coating layer may comprise a plurality of nanostructures formed from the material of the coating layer.
  • etching is performed using a plasma.
  • a second method step 452 comprises forming an etched coating layer 437 comprising a plurality of nanostructures 435 by etching coating layer 433 using a second plasma 422.
  • a plasma used for etching comprises a reactive species such as oxygen, argon, helium, neon, krypton, xenon, or combination thereof.
  • a reactive species may, upon contacting a coating layer, etch the coating layer by reacting with a polymer of the coating layer.
  • An etching process may result in the formation of a plurality of nanostructures by removing material between the nanostructures.
  • An etched coating layer may have an increased oleophobicity and/or hydrophobicity relative to a similar smooth coating layer. An increased oleophobicity and/or hydrophobicity may result from the mechanism described above with reference to FIG.
  • a coating layer is plasma-etched in a chamber having a pressure of less than or equal to 100 Pa, less than or equal to 95 Pa, less than or equal to 90 Pa, less than or equal to 85 Pa, less than or equal to 80 Pa, less than or equal to 75 Pa, less than or equal to 70 Pa, less than or equal to 65 Pa, less than or equal to 60 Pa, less than or equal to 55 Pa, less than or equal to 50 Pa, less than or equal to 45 Pa, less than or equal to 40 Pa, less than or equal to 35 Pa, less than or equal to 30 Pa, less than or equal to 25 Pa, less than or equal to 20 Pa, or less than or equal to 15 Pa.
  • a plasma for etching a coating layer may have any of a variety of suitable powers.
  • a coating layer is etched using a plasma having a power of greater than or equal to 400 W, greater than or equal to 450 W, greater than or equal to 500 W, greater than or equal to 550 W, greater than or equal to 600 W, greater than or equal to 650 W, greater than or equal to 700 W, greater than or equal to 750 W, greater than or equal to 800 W, greater than or equal to 850 W, greater than or equal to 900 W, greater than or equal to 950 W, greater than or equal to 1000 W, or greater than or equal to 1050 W.
  • a coating layer is etched using a plasma having a power of less than or equal to 1100 W, less than or equal to 1050 W, less than or equal to 1000 W, less than or equal to 950 W, less than or equal to 900 W, less than or equal to 850 W, less than or equal to 800 W, less than or equal to 750 W, less than or equal to 700 W, less than or equal to 650 W, less than or equal to 600 W, less than or equal to 550 W, less than or equal to 500 W, or less than or equal to 450 W. Combinations of these ranges are also possible (e.g., greater than or equal to 400 W and less than or equal to 1100 W or greater than or equal to 500 W and less than or equal to 1000 W). Other ranges are also possible.
  • a plasma to etch a uniform coating layer to form nanostructures may present a number of technical challenges on certain coating layers. For example, in some embodiments it is desirable for a plasma to etch different portions of a coating layer at different rates (e.g., in order to form nanostructures).
  • a method described herein involves heterogeneous etching of a coating layer (i.e., the formation of heterogeneous nanostructures on the coating layer). Heterogeneous etching of a coating layer may be performed using an electrode (e.g., involving a sputtering process). This technique may have advantages for the formation of nanostructures on face mask surfaces.
  • Material from an electrode may be sputtered onto a surface of layer (e.g., onto a surface of a support layer such as a first layer or a third layer) that is opposite the electrode.
  • a sputtered material may have the form of nanoparticles (e.g., metal nanoparticles).
  • a material is sputtered from an exposed portion of an electrode (e.g., a portion of an electrode that is directly exposed to a plasma).
  • nanoparticles sputtered onto a surface of an electrode may result in the formation of nanostructures. Nanostructures may form for any of a variety of appropriate reasons.
  • charged nanoparticles may repel an etching plasma, reducing local etching.
  • nanoparticles may act as nucleation sites around which nanostructures may develop.
  • nanostructures form through other mechanisms, or through a variety of mechanisms acting in combination.
  • a plasma used to deposit a coating layer comprising a composition gradient may have any of a variety of appropriate powers and pressures, including the powers and pressures described in the context of coating layer deposition, above.
  • plasmas with pressures of greater than or equal to 20 Pa and less than or equal to 60 Pa have been found to be advantageous for depositing coating layers with composition gradients.
  • plasmas with powers of greater than or equal to 700 W and less than or equal to 1000 W have been found to be advantageous for depositing coating layers with composition gradients.
  • composition gradients of coating layers on a coating layer may preserve desirable surface properties (e.g., high hydrophobicity and/or oleophobicity) while preserving mechanical compatibility between the coating layers and the coating layer.
  • a first coating layer and a second coating layer may have the same or different compositions.
  • a first coating layer and a second coating layer may have a same or different composition gradients.
  • one or more coating layers on a coating layer may have a polymerize silane and/or or a polymerized siloxane concentration that increases with distance away from the coating layer (e.g., across a thickness of the coating layer(s)). In some embodiments, it may be advantageous for one or more coating layers on a coating layer to have an organic polymer concentration that decreases with distance away from the coating layer (e.g., across a thickness of the coating layer(s)).
  • a coating layer comprising a composition gradient may be etched, but the disclosure is not limited to coating layers that have been etched.
  • a coating layer comprising a composition gradient may be deposited on top of a plurality of nanostructures, but the disclosure is not limited to coating layers that have been deposited on a plurality of nanostructures.
  • a face mask formed as described herein may repel oil and/or water.
  • the ability of a face mask to repel oil and/or water may be related to a surface energy of a surface of the face mask.
  • surface features e.g., nanostructures or coating layers deposited thereon
  • Such improvements in oil and/or water repellency may result from trapping of air between nanostructures, which may reduce the ability of liquids like oil and water to wet a surface of a face mask, however other mechanisms are also possible.
  • Oil and/or water repellency may be desirable for a number of applications, particularly in the context of face masks.
  • a surface of a face mask described herein is hydrophobic.
  • water contacting a hydrophobic surface of a face mask has a contact angle.
  • a face mask described herein may have any of a variety of suitable contact angles with water.
  • a hydrophobic surface of a face mask has a water contact angle of greater than or equal to 90°, greater than or equal to 95°, greater than or equal to 100°, greater than or equal to 105°, greater than or equal to 110°, greater than or equal to
  • a hydrophobic surface of a face mask has a water contact angle of less than or equal to 180°, less than or equal to 175°, less than or equal to 170°, less than or equal to 165°, less than or equal to 160°, less than or equal to 155°, less than or equal to 150°, less than or equal to 145°, less than or equal to 130°, less than or equal to 125°, less than or equal to 120°, less than or equal to 115°, less than or equal to 110°, less than or equal to 105°, less than or equal to 100°, or less than or equal to 95°.
  • hydrophobicity of a surface of a face mask is characterized by its hydrophobicity rank.
  • a surface of a face mask has a hydrophobicity rank of greater than or equal to 1, greater than or equal to 2, greater than or equal to 3, greater than or equal to 4, greater than or equal to 5, greater than or equal to 6, or greater than or equal to 7.
  • a surface of a face mask has a hydrophobicity rank of less than or equal to 8, less than or equal to 7, less than or equal to 6, less than or equal to 5, less than or equal to 4, less than or equal to 3, or less than or equal to 2.
  • a test solution with a 60:40 water: isopropyl alcohol (vol: vol) with a surface tension of 25.4 mN/m does not wet the surface of the face mask within 10 seconds
  • a test solution with a 50:50 water:isopropyl alcohol (vokvol) with a surface tension of 24.5 mN/m wets the surface of the face mask within 10 seconds
  • the surface of the face mask has a hydrophobicity rank of 6.
  • fluorinated polymers are often used to produce oleophobic and/or hydrophobic coating layers.
  • the use of fluorinated polymers is not environmentally friendly.
  • One advantage of the methods and face masks described herein is that they may provide oleophobic and/or hydrophobic surfaces using nanostructures and/or coating layers without fluorine, or with only trace amounts of fluorine.
  • a face mask described herein comprises a plurality of nanostructures that comprises less than or equal to 0.5 at%, less than or equal to 0.4 at%, less than or equal to 0.3 at%, less than or equal to 0.2 at%, less than or equal to 0.1 at%, less than or equal to 0.08 at%, less than or equal to 0.05 at%, less than or equal to 0.02 at%, less than or equal to 0.01 at%, less than or equal to 0.008 at%, less than or equal to 0.005 at%, or less than or equal to 0.002 at% fluorine atoms.
  • a face mask described herein comprises a plurality of nanostructures that comprises greater than or equal to 0 at%, or greater than or equal to 0.001 at% fluorine atoms.
  • the nanostructures increase the roughness of a face mask.
  • a face mask described herein may comprise a surface having any of a variety of suitable root mean squared (RMS) roughness values.
  • a face mask described herein comprises a surface having a roughness of greater than or equal to 0.05 microns, greater than or equal to 0.1 microns, greater than or equal to 0.2 microns, greater than or equal to 0.3 microns, greater than or equal to 0.4 microns, greater than or equal to 0.5 microns, greater than or equal to 0.6 microns, greater than or equal to 0.7 microns, greater than or equal to 0.8 microns, greater than or equal to 0.9 microns, greater than or equal to 0.10 microns, greater than or equal to 0.11 microns, or greater than or equal to 0.12 microns, greater than or equal to 0.13 microns, greater than or equal to 0.14 microns, greater than or equal to 0.15 microns, or greater than or equal to
  • RMS roughness of a face mask may be determined by atomic force microscopy.
  • a face mask described herein may comprise nanostructures having any of a variety of suitable diameters.
  • a face mask comprises a plurality of nanostructures having an average diameter of greater than or equal to 0.05 microns, greater than or equal to 0.08 microns, greater than or equal to 0.1 microns, greater than or equal to 0.12 microns, greater than or equal to 0.15 microns, greater than or equal to 0.18 microns, greater than or equal to 0.2 microns, greater than or equal to 0.05 microns, greater than or equal to 0.22 microns, greater than or equal to 0.25 microns, greater than or equal to 0.28 microns, greater than or equal to 0.3 microns, greater than or equal to 0.32 microns, greater than or equal to 0.35 microns, greater than or equal to 0.38 microns, greater than or equal to 0.4 microns, or greater than or equal to 0.42 microns.
  • a face mask comprises a plurality of nanostructures having an average diameter of less than or equal to 0.45 microns, less than or equal to 0.42 microns, less than or equal to 0.4 microns, less than or equal to 0.38 microns, less than or equal to 0.35 microns, less than or equal to 0.32 microns, less than or equal to 0.3 microns, less than or equal to 0.28 microns, less than or equal to 0.25 microns, less than or equal to 0.22 microns, less than or equal to 0.2 microns, less than or equal to 0.18 microns, less than or equal to 0.15 microns, less than or equal to 0.12 microns, or less than or equal to 0.1 microns.
  • the nanostructure diameter may be determined by atomic force microscopy.
  • a face mask comprises a plurality of nanostructures having an standard deviation in diameter of greater than or equal to 0.005 microns, greater than or equal to 0.008 microns, greater than or equal to 0.01 microns, greater than or equal to 0.012 microns, greater than or equal to 0.015 microns, greater than or equal to 0.018 microns, greater than or equal to 0.02 microns, greater than or equal to 0.022 microns, greater than or equal to 0.025 microns, greater than or equal to 0.028 microns, greater than or equal to 0.03 microns, or greater than or equal to 0.032 microns.
  • a face mask comprises a plurality of nanostructures having an standard deviation in diameter of less than or equal to 0.035 microns, less than or equal to 0.032 microns, less than or equal to 0.03 microns, less than or equal to 0.028 microns, less than or equal to 0.025 microns, less than or equal to 0.022 microns, less than or equal to 0.02 microns, less than or equal to 0.018 microns, less than or equal to 0.015 microns, less than or equal to 0.012 microns, less than or equal to 0.01 microns, or less than or equal to 0.008 microns.
  • a face mask described herein may comprise nanostructures having any of a variety of suitable aspect ratios of nanostructure height to nanostructure diameter.
  • a face mask comprises a plurality of nanostructures having an average aspect ratio of greater than or equal to 0.5, greater than or equal to 0.6, greater than or equal to 0.7, greater than or equal to 0.8, greater than or equal to 0.9, greater than or equal to 1, greater than or equal to 2, greater than or equal to 3, greater than or equal to 4, greater than or equal to 5, greater than or equal to 6, greater than or equal to 7, greater than or equal to 8, greater than or equal to 9, greater than or equal to 10, greater than or equal to 11, or greater than or equal to 12.
  • a plurality of nanostructures may be disposed in any of a variety of suitable arrangements.
  • the nanostructures may be arranged in an ordered grid.
  • the nanostructures have a random arrangement.
  • a random arrangement of nanostructures may be uniformly random, or may simply have a stochastic spatial distribution with high local concentrations of nanostructures in some areas and low local concentrations of nanostructures in others.
  • One advantage of random arrangements of nanostructures may be scalability. For example, in some embodiments it is easier to fabricate random arrangements of nanostructures over large coating layer areas. Thus, random arrangements of nanostructures may have particular advantages for the use of nanostructures in face mask surfaces.
  • a face mask described herein may comprise nanostructures having any of a variety of suitable peak to peak spacings.
  • a face mask comprises a plurality of nanostructures having an average peak-to-peak spacing of greater than or equal to 0.2 microns, greater than or equal to 0.5 microns, greater than or equal to 0.8 microns, greater than or equal to 1 micron, greater than or equal to 1.2 microns, greater than or equal to 1.5 microns, greater than or equal to 1.8 microns, greater than or equal to 2 microns, or greater than or equal to 2.2 microns.
  • a face mask comprises a plurality of nanostructures having an average peak-to-peak spacing of less than or equal to 2.5 microns, less than or equal to 2.2 microns, less than or equal to 2 microns, less than or equal to 1.8 microns, less than or equal to 1.5 microns, less than or equal to 1.2 microns, less than or equal to 1 micron, less than or equal to 0.8 microns, less than or equal to 0.5 microns, or less than or equal to 0.2 microns. Combinations of these ranges are also possible (e.g., greater than or equal to 0.2 microns and less than or equal to 2.5 microns or greater than or equal to 0.2 microns and less than or equal to 2.2 microns). Other ranges are also possible.
  • a face mask comprises a plurality of nanostructures having a standard deviation in peak-to-peak spacing of greater than or equal to 0.001 microns, greater than or equal to 0.002 microns, greater than or equal to 0.005 microns, greater than or equal to 0.01 microns, greater than or equal to 0.02 microns, greater than or equal to 0.05 microns, greater than or equal to 0.08 microns, greater than or equal to 0.1 microns, greater than or equal to 0.2 microns, greater than or equal to 0.3 microns, or greater than or equal to 0.4 microns.
  • a face mask comprises a plurality of nanostructures having a standard deviation in peak-to-peak spacing of less than or equal to 0.5 microns, less than or equal to 0.4 microns, less than or equal to 0.3 microns, less than or equal to 0.2 microns, less than or equal to 0.1 microns, less than or equal to 0.08 microns, less than or equal to 0.05 microns, less than or equal to 0.02 microns, less than or equal to 0.01 microns, less than or equal to 0.008 microns, less than or equal to 0.005 microns, or less than or equal to 0.002 microns. Combinations of these ranges are also possible (e.g., greater than or equal to 0.001 microns and less than or equal to 0.5 microns). Other ranges are also possible.
  • a hydrophilic surface of a layer may be produced using a plasma.
  • the plasma may be used to deposit a polymeric coating layer at a surface of a layer (e.g., a support layer that may be a first layer or a third layer).
  • the plasma may comprise a monomer, as described above.
  • a plasma used to make a hydrophilic coating layer comprises an organic monomer such as ethylene, butadiene acetylene, methane, methanol, or ethanol.
  • the organic monomer may be a hydrocarbon monomer (e.g., ethylene, butadiene, acetylene, or methane).
  • the plasma may comprise one or more, oxygen, argon, or a combination thereof.
  • a hydrophilic moiety precursor reacts with monomers of a plasma prior to deposition of the monomers onto a layer. Reaction of the monomers with the reactive species may result in the formation of radicalized monomers of the plasma.
  • a plasma used to deposit a hydrophilic coating layer comprises a reactive species.
  • a plasma may comprise a reactive species such as such as oxygen, argon, helium, neon, krypton, xenon, or combination thereof.
  • a reactive species reacts with monomers of a plasma prior to deposition of the monomers onto a layer. Reaction of the monomers with the reactive species may result in the formation of radicalized monomers of the plasma. Radicalized monomers may deposit on the layers at different rates, and may impact the plasma conditions appropriate for coating layer deposition.
  • the hydrophilicity of a surface of a face mask may be determined by its water contact angle (discussed above, in the context of hydrophobic water contact angles), according to some embodiments.
  • a face mask described herein may have any of a variety of suitable contact angles with water.
  • a hydrophilic surface of a face mask has a water contact angle of greater than or equal to 0°, greater than or equal to 2°, greater than or equal to 5°, greater than or equal to 8°, greater than or equal to 10°, greater than or equal to 12°, greater than or equal to 15°, greater than or equal to 18°, greater than or equal to 20°, greater than or equal to 22°, greater than or equal to 25°, or greater than or equal to 28°, or greater.
  • a hydrophilic surface of a face mask has a water contact angle of less than or equal to 30°, less than or equal to 28°, less than or equal to 25°, less than or equal to 22°, less than or equal to 20°, less than or equal to 18°, less than or equal to 15°, less than or equal to 12°, less than or equal to 10°, less than or equal to 8°, less than or equal to 5°, less than or equal to 2°, or less. Combinations of these ranges are also possible (e.g., greater than or equal to 0° and less than or equal to 30°, greater than or equal to 0° and less than or equal to 10°, or greater than or equal to 0° and less than or equal to 5°). Other ranges are also possible.
  • the contact angle may be measured by the sessile drop technique.
  • a plasma used for hydrophilic coating layer deposition may comprise its constituents at any of a variety of appropriate flow rates.
  • a plasma described herein may comprise ethylene having any of a variety of suitable flow rates.
  • a plasma comprises ethylene having a flow rate of greater than or equal to 4 seem, greater than or equal to 5 seem, greater than or equal to 6 seem, greater than or equal to 7 seem, greater than or equal to 8 seem, greater than or equal to 9 seem, greater than or equal to 10 seem, greater than or equal to 12 seem, greater than or equal to 14 seem, greater than or equal to 16 seem, greater than or equal to 18 seem, greater than or equal to 20 seem, greater than or equal to 22 seem, greater than or equal to 24 seem, greater than or equal to 26 seem, greater than or equal to 28 seem, or greater than or equal to 30 seem.
  • a plasma comprises ethylene having a flow rate of less than or equal to 32 seem, less than or equal to 30 seem, less than or equal to 28 seem, less than or equal to 26 seem, less than or equal to 24 seem, less than or equal to 22 seem, less than or equal to 20 seem, less than or equal to 18 seem, less than or equal to 16 seem, less than or equal to 14 seem, less than or equal to 12 seem, less than or equal to 10 seem, less than or equal to 9 seem, less than or equal to 8 seem, less than or equal to 7 seem, less than or equal to 6 seem, less than or equal to 5 seem, or less than or equal to 4 seem.
  • a plasma described herein may comprise ammonia having any of a variety of suitable flow rates.
  • a plasma comprises ammonia having a flow rate of greater than or equal to 4 seem, greater than or equal to 8 seem, greater than or equal to 12 seem, greater than or equal to 16 seem, greater than or equal to 20 seem, greater than or equal to 24 seem, greater than or equal to 28 seem, greater than or equal to 32 seem, greater than or equal to 36 seem, greater than or equal to 40 seem, greater than or equal to 44 seem, greater than or equal to 48 seem, greater than or equal to 52 seem, greater than or equal to 56 seem, or greater than or equal to 60 seem.
  • a plasma described herein may comprise carbon dioxide having any of a variety of suitable flow rates.
  • a plasma comprises carbon dioxide having a flow rate of greater than or equal to 8 seem, greater than or equal to 16 seem, greater than or equal to 24 seem, greater than or equal to 32 seem, greater than or equal to 40 seem, greater than or equal to 48 seem, greater than or equal to 56 seem, greater than or equal to 64 seem, greater than or equal to 72 seem, greater than or equal to 80 seem, greater than or equal to 88 seem, greater than or equal to 96 seem, greater than or equal to 104 seem, greater than or equal to 112 seem, or greater than or equal to 120 seem.
  • a plasma comprises carbon dioxide having a flow rate of less than or equal to 128 seem, less than or equal to 120 seem, less than or equal to 112 seem, less than or equal to 104 seem, less than or equal to 96 seem, less than or equal to 88 seem, less than or equal to 80 seem, less than or equal to 72 seem, less than or equal to 64 seem, less than or equal to 56 seem, less than or equal to 48 seem, less than or equal to 40 seem, less than or equal to 32 seem, or less than or equal to 24 seem.
  • a plasma described herein may comprise hexamethyldisiloxane having any of a variety of suitable flow rates.
  • a plasma comprises hexamethyldisiloxane having a flow rate of greater than or equal to 8 seem, greater than or equal to 10 seem, greater than or equal to 12 seem, greater than or equal to 14 seem, greater than or equal to 16 seem, greater than or equal to 18 seem, greater than or equal to 20 seem, greater than or equal to 24 seem, greater than or equal to 28 seem, greater than or equal to 32 seem, greater than or equal to 36 seem, greater than or equal to 40 seem, or greater than or equal to 44 seem.
  • a plasma comprises hexamethyldisiloxane having a flow rate of less than or equal to 48 seem, less than or equal to 44 seem, less than or equal to 40 seem, less than or equal to 36 seem, less than or equal to 32 seem, less than or equal to 28 seem, less than or equal to 24 seem, less than or equal to 20 seem, less than or equal to 18 seem, less than or equal to 16 seem, less than or equal to 14 seem, less than or equal to 12 seem, or less than or equal to 10 seem.
  • a plasma comprises oxygen having a flow rate of greater than or equal to 20 seem, greater than or equal to 24 seem, greater than or equal to 28 seem, greater than or equal to 32 seem, greater than or equal to 36 seem, greater than or equal to 40 seem, greater than or equal to 44 seem, greater than or equal to 48 seem, greater than or equal to 52 seem, greater than or equal to 56 seem, or greater than or equal to 60 seem.
  • a plasma comprises oxygen having a flow rate of less than or equal to 64 seem, less than or equal to 60 seem, less than or equal to 56 seem, less than or equal to 52 seem, less than or equal to 48 seem, less than or equal to 44 seem, less than or equal to 40 seem, less than or equal to 36 seem, less than or equal to 32 seem, less than or equal to 28 seem, or less than or equal to 24 seem. Combinations of these ranges are also possible (e.g., greater than or equal to 20 seem and less than or equal to 64 seem, greater than or equal to 32 seem and less than or equal to 56 seem, or greater than or equal to 40 seem and less than or equal to 52 seem). Other ranges are also possible.
  • a plasma described herein may comprise argon having any of a variety of suitable flow rates.
  • a plasma comprises argon having a flow rate of greater than or equal to 2 seem, greater than or equal to 4 seem, greater than or equal to 6 seem, greater than or equal to 8 seem, greater than or equal to 10 seem, greater than or equal to 12 seem, greater than or equal to 14 seem, greater than or equal to 16 seem, greater than or equal to 18 seem, greater than or equal to 20 seem, or greater than or equal to 22 seem.
  • a plasma comprises argon having a flow rate of less than or equal to 24 seem, less than or equal to 22 seem, less than or equal to 20 seem, less than or equal to 18 seem, less than or equal to 16 seem, less than or equal to 14 seem, less than or equal to 12 seem, less than or equal to 10 seem, less than or equal to 8 seem, or less than or equal to 6 seem. Combinations of these ranges are also possible (e.g., greater than or equal to 2 seem and less than or equal to 24 seem, greater than or equal to 6 seem and less than or equal to 18 seem, or greater than or equal to 10 seem and less than or equal to 16 seem). Other ranges are also possible.
  • a face mask described herein may have any of a variety of suitable bacterial filtration efficiencies.
  • a face mask has a bacterial filtration efficiency of greater than or equal to 90%, greater than or equal to 91%, greater than or equal to 92%, greater than or equal to 93%, greater than or equal to 94%, greater than or equal to 95%, greater than or equal to 96%, greater than or equal to 97%, greater than or equal to 98%, greater than or equal to 99%, or greater than or equal to 99.5%.
  • a face mask has a bacterial filtration efficiency of less than or equal to 99.9%, less than or equal to 99.5%, less than or equal to 99%, less than or equal to 98%, less than or equal to 97%, less than or equal to 96%, less than or equal to 95%, less than or equal to 94%, less than or equal to 93%, less than or equal to 92%, or less than or equal to 91%. Combinations of these ranges are also possible (e.g., greater than or equal to 90% and less than or equal to 99.9%, greater than or equal to 95% and less than or equal to 99.9%, or greater than or equal to 98% and less than or equal to 99.9%). Other ranges are also possible.
  • the sub-micron filtration efficiency may be conducted with test equipment (e.g., TSI or equivalent) set to meet the following parameters: the NaCl aerosol has a size distribution with count median diameter (CMD) of 0.075 ⁇ 0.020 pm and a standard geometric deviation (SGD) not exceeding 1.86.
  • CMD count median diameter
  • SGD standard geometric deviation
  • the particles may be neutralized to the Boltzmann equilibrium state.
  • the mask may be tested at a flow rate of 60 L/min ⁇ 4 L/min.
  • the entire mask may be sealed for testing to prevent leakage.
  • the environmental temperature may be 25 ⁇ 5 °C and the relative humidity may be 30 ⁇ 10 %.
  • a tone transmitted through a face mask has a relatively low attenuation relative to an identical tone transmitted from the same source without the face mask.
  • a tone transmitted through a face mask is attenuated by less than or equal to, less than or equal to 9 dB, less than or equal to 8 dB, less than or equal to 7 dB, less than or equal to 6 dB, less than or equal to 5 dB, less than or equal to 4 dB, less than or equal to 3 dB, or less than or equal to 2 dB.
  • a tone transmitted through a face mask is attenuated by greater than or equal to 1 dB, greater than or equal to 2 dB, greater than or equal to 3 dB, greater than or equal to 4 dB, greater than or equal to 5 dB, greater than or equal to 6 dB, greater than or equal to 7 dB, greater than or equal to 8 dB, or greater than or equal to 9 dB.
  • Combinations of these ranges are also possible (e.g., greater than or equal to 1 dB and less than or equal to 10 dB, greater than or equal to 1 dB and less than or equal to 6 dB, greater than or equal to 3 dB and less than or equal to 5 dB, or greater than or equal to 3 dB and less than or equal to 4 dB).
  • Other ranges are also possible.
  • the attenuated tone may have any of a variety of appropriate frequencies.
  • an attenuated tone has a frequency of greater than or equal to 20 Hz, greater than or equal to 50 Hz, greater than or equal to 100 Hz, greater than or equal to 150 Hz, greater than or equal to 200 Hz, greater than or equal to 500 Hz, greater than or equal to 1,000 Hz, greater than or equal to 2,000 Hz, greater than or equal to 3,000 Hz, greater than or equal to 4,000 Hz, greater than or equal to 5,000 Hz, greater than or equal to 6,000 Hz, greater than or equal to 7,000 Hz, greater than or equal to 8,000 Hz, greater than or equal to 9,000 Hz, greater than or equal to 10,000 Hz, greater than or equal to 12,000 Hz, greater than or equal to 14,000 Hz, greater than or equal to 16,000 Hz, or greater than or equal to 18,000 Hz.
  • an attenuated tone has a frequency of less than or equal to 20,000 Hz, less than or equal to 18,000 Hz, less than or equal to 16,000 Hz, less than or equal to 14,000 Hz, less than or equal to 12,000 Hz, less than or equal to 10,000 Hz, less than or equal to 9,000 Hz, less than or equal to 8,000 Hz, less than or equal to 7,000 Hz, less than or equal to 6,000 Hz, less than or equal to 5,000 Hz, less than or equal to 4,000 Hz, less than or equal to 3,000 Hz, less than or equal to 2,000 Hz, less than or equal to 1,000 Hz, less than or equal to 500 Hz, less than or equal to 500 Hz, less than or equal to 200 Hz, or less than or equal to 150 Hz.
  • Combinations of these ranges are also possible (e.g., greater than or equal to 20 Hz and less than or equal to 20,000 Hz, greater than or equal to 150 Hz and less than or equal to 10,000 Hz, or greater than or equal to 500 Hz and less than or equal to 10,000 Hz). Other ranges are also possible.
  • the attenuation of the tone may be determined in an anechoic chamber by the following procedure.
  • a tone may be generated by a head and torso simulator (e.g., a GRAS head and torso simulator) that plays white noise through the artificial mouth (KEMAR 45BC or equivalent manikin with mouth simulator and loudspeaker), with or without a face mask.
  • An output acoustic signal may be measured and recorded by a microphone located at 6 ft distance from the loudspeaker.
  • the attenuation may be measured as the drop in sensed sound intensity when the mask is used, relative to a sound intensity sensed without the mask.
  • the face mask attenuates a tone by less than or equal to 10 dB, less than or equal to 6 dB, less than or equal to 5 dB, or less than or equal to 4 dB for a tone having a frequency between or equal to 20 Hz and 20,000 Hz, 150 Hz and 10,000 Hz, for a tone generated by a head and torso simulator with a loudspeaker located 6 ft from a recording microphone, relative to the intensity of the tone in the absence of the face mask.
  • a face mask described herein is resistant to flame spread. Flame spread resistance may be measured by the test method outlined in 16 CFR Part 1610 (2008). Briefly, a face mask material may be mounted at an angle in a chamber. Near the top of the material, a weighted thread may be configured to fall when the weighted thread is burned. A flame may be brought close to the bottom of the face mask material to ignite the face mask material for 1.0 seconds. A material is resistant to flame spread if the ignition of the bottom of the face mask does not bum the weighted thread, causing the weight to fall.
  • a face mask described herein is biocompatible. A face mask may be biocompatible if it has a relatively low minimal essential media elution (MEM) score.
  • MEM minimal essential media elution
  • the MEM score may be determined using ANSVAAMVISO 10993-5. Briefly, an extract of the face mask may be prepared by agitation of the face mask in MEM with 5% bovine serum for 24 hours at 37 degrees. The extract of the face mask may then be added to industry standard L-929 (ATCC CCL-1) cell monolayers and incubated for 72 hours at 37 degrees and 5% CO2. The cell monolayers may be examined and scored based on the degree of cellular destruction to determine the MEM score.
  • industry standard L-929 ATCC CCL-1
  • a method of making a face mask comprises obtaining a first, support layer and depositing a second, filtration layer on top of the first, support layer.
  • the second layer may be deposited by any of a variety of appropriate methods.
  • the second layer e.g., a filtration layer
  • electrospinning e.g., melt electrospinning or solvent electrospinning.
  • a third, support layer may be deposited on the second, filtration layer using any of a variety of appropriate methods.
  • the third, support layer may be laminated (e.g., heat-laminated, adhesive-laminated) on top of the second, filtration layer.
  • the resulting structure, comprising the first, support layer, the second, filtration layer, and the third, support layer may then be formed into a face mask by any of a variety of appropriate methods.
  • a method of making a face mask is provided.
  • a face mask is made by obtaining a first, support layer and depositing a second, filtration layer on top of the first, support layer to produce a first bilayered article.
  • a face mask is made by obtaining a third, support layer and depositing a fourth, filtration layer on the third, support layer to produce a second bi-layered article.
  • the second bi-layered article may then be deposited on the first bi-layered article such that the second, filtration layer and the fourth, filtration layer are disposed between the first, support layer and the third, support layer.
  • the second bi- layered article may be deposited on the first bi-layered article by any of a variety of appropriate methods.
  • the second bi-layered article may be laminated to the first bi-layered article.
  • the bi-layered articles are laminated directly together, leaving an interface between the second, filtration layer and the fourth, filtration layer.
  • the bi-layered articles are laminated using an adhesive, leaving an adhesive disposed between the second, filtration layer and the fourth, filtration layer.
  • a fifth, separation layer is obtained and the bi-layered articles are laminated together such that the fifth, separation layer is disposed between and separates the second, filtration layer and the fourth, filtration layer.
  • the resulting structure may then be formed into a face mask by any of a variety of appropriate methods.
  • the face mask is produced and used without heating. It has been recognized that heating may melt the fibers of a fiber web (e.g., a fiber web of a first layer, a second layer, a third layer, a fourth layer), producing a fused- fiber structure, according to some embodiments.
  • a fiber web e.g., a fiber web of a first layer, a second layer, a third layer, a fourth layer
  • the fused fiber structure may improve mechanical strength of a fiber web, but may also increase the scattering from the fused fiber structure. This may result in an undesirably low transparency in some, but not necessarily all embodiments.
  • the face mask may, in some embodiments, be produced such that an external surface of the face mask (e.g., a surface facing outward from a face of a wearer, during use) is hydrophobic, as discussed above.
  • the face mask may, in some embodiments, be produced such that an internal surface of the face mask (e.g., a surface facing inward, towards a face of a wearer during use) is hydrophilic.
  • a face mask (or an article suitable for use in a face mask) is folded (e.g., so that its final configuration is pleated) such that it can be more readily or conformally contoured against a curved surface, such as curved facial features.
  • a face mask may comprise one or more pleats that, when the face mask is worn, at least partially unfold to allow the face mask to better conform to the curves and features of the face of a wearer.
  • a face mask comprises greater than or equal to
  • a face mask comprises less than or equal to 5 pleats, less than or equal to 4 pleats, less than or equal to 3 pleats, or less than or equal to
  • face masks are pleated with three pleats.
  • conventional, three-pleated face masks typically include a pleat that is positioned over or in close proximity to the mouth of a mask wearer when in use.
  • the extra layers of filter material associated with such a pleat positioned over or in close proximity to the mouth of a mask wearer tends to reduce the transmission of light through the pleat, relative to the transmission of light through a single-layered, non-folded portion of the transparent face mask and/or otherwise visually distort or render less visible the mouth of the wearer.
  • FIGS. 6A-6B show a schematic illustration of a non-limiting, two-pleated face mask, according to some embodiments.
  • FIG. 6A shows a top-view of a side of a two- pleated face mask 601 that would not be in contact with the wearer’s face, laid flat.
  • Mask 601 comprises filter material 602 comprising two pleats 603.
  • Mask 601 is laminated to nose strip 605 and ear loops 607.
  • FIG. 6B shows a perspective, schematic illustration of mask 601, contoured as it would be when worn. As shown, portion 611 of face mask 601 between pleats 603, which would rest over a wearer’s mouth, is not pleated and would thus provide improved visual clarity of the wearer’s facial expression relative to a conventional three-pleated design.
  • FIG. 7 presents a photograph of a non-limiting two-pleated transparent mask 701 contoured around a sculpted head 725 (black form).
  • mask 701 is transparent, permitting observation of sculpted head 725 through mask 701.
  • Pleated portion 703 results in multi-layered filter material that visually obscures/distorts visualization of the portion of sculpted head 725 that it overlays, resulting in a whiter coloration and greater opacity.
  • this pleated, multilayer portion does not overlay the mouth of the wearer, and rather a single-layer portion 711 of mask 701 is not pleated is positioned to cover the mouth of a wearer.
  • a face mask may be pleated using any of a variety of suitable conventional methods known to the skilled artisan, and the disclosure is not limited to any particular pleating method or manufacturing equipment.
  • the mask is configured to be pleated using a pleat-roller in a conventional pleating machine.
  • FIG. 8 presents a photograph of a non-limiting pleat-roller 801 that is configured to form two pleats, e.g. as illustrated above in the embodiment shown in FIGS. 6A, 6B, and 7, in filter material used to form masks.
  • the pleats can be formed, for example using a pleat forming roller(s) 801 including two pleat- forming flange portions 803 and 805 position in a pleat forming machine for face mask filter media (for example a Medical Mask Machine available from RDI Medical, Itasca, IL USA).
  • a pleat forming roller(s) 801 including two pleat- forming flange portions 803 and 805 position in a pleat forming machine for face mask filter media for example a Medical Mask Machine available from RDI Medical, Itasca, IL USA.
  • This example describes the preparation and properties of a non-limiting facemask, according to some embodiments.
  • an article was prepared. The article was prepared using a first, support layer comprising a Nylon/PLA mesh. A second, filtration layer of the article was electrospun on top of the first, support layer, the second, filtration layer comprising fibers with an average diameter of greater than or equal to 100 nm and less than or equal to 280 nm. A third, support layer comprising a Nylon/PLA mesh was laminated such that the second layer was disposed between the first layer and the third layer. A nose strip was laminated onto the article, and the article was folded to include pleats. A side of the article was laminated to preserve the folded pleats, and ear loops were laminated onto the article. The resulting article was a face mask with a high optical transparency.
  • FIG. 5 presents the attenuation associated with each of the face masks. As shown, attenuation over the audible range was generally lower for the transparent face masks, and typically stayed below a 6 dB attenuation threshold that has been set as a desired industry standard, outperforming both the N95 and the commercial 4-ply masks. This result demonstrates the improved sound transmission through non-limiting transparent face masks as described herein.
  • the resulting mask is pleated such that the pleats do not cover the mouth of the wearer when in use by a typical wearer, thus providing the appearance and communication advantages of two-pleated designs for transparent masks described above.
  • a reference to “A and/or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.
  • “at least one of A and B” can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.
  • wt% is an abbreviation of weight percentage.
  • at% is an abbreviation of atomic percentage.
  • embodiments may be embodied as a method, of which various examples have been described.
  • the acts performed as part of the methods may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include different (e.g., more or less) acts than those that are described, and/or that may involve performing some acts simultaneously, even though the acts are shown as being performed sequentially in the embodiments specifically described above.

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Abstract

L'invention concerne de manière générale des masques faciaux transparents, et des traitements associés. Les masques faciaux transparents selon l'invention peuvent présenter un certain nombre d'avantages, notamment une visibilité améliorée des expressions faciales d'un utilisateur, une capacité améliorée à repousser des fluides externes, une résistance améliorée à l'absorption de fluides externes, et un amortissement réduit du son à travers le masque facial. L'invention concerne également des méthodes de traitement associées qui peuvent, dans certains modes de réalisation, contribuer à un ou plusieurs de ces avantages.
PCT/IB2025/000038 2024-02-05 2025-02-04 Articles transparents et masques faciaux et traitements associés Pending WO2025169010A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100239625A1 (en) * 2007-03-02 2010-09-23 Puckett Anne Mcintosh Transparent antimicrobial face mask
WO2016052401A1 (fr) * 2014-09-30 2016-04-07 花王株式会社 Masque hygiénique
WO2016194353A1 (fr) * 2015-06-04 2016-12-08 日東電工株式会社 Masque

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100239625A1 (en) * 2007-03-02 2010-09-23 Puckett Anne Mcintosh Transparent antimicrobial face mask
WO2016052401A1 (fr) * 2014-09-30 2016-04-07 花王株式会社 Masque hygiénique
WO2016194353A1 (fr) * 2015-06-04 2016-12-08 日東電工株式会社 Masque

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