BIOCOMPATIBLE SPACE-CHARGED ELECTRET MATERIALS WITH ANTIBACTERIAL AND ANTIVIRAL EFFECTS AND METHODS OF MANUFACTURE THEREOF
20230097006 · 2023-03-30
Inventors
Cpc classification
A01P1/00
HUMAN NECESSITIES
International classification
Abstract
The present disclosure relates to antiviral, antibacterial, virucidal and/or bactericidal space-charge electret materials and compositions comprising space-charge electret materials; methods of making and using the materials, methods of making and using the compositions, methods of evaluating the efficacy of the compositions, methods of measuring and testing the compositions, and methods of developing, creating and making new space-charge electret compositions.
Claims
1. An antiviral material, comprising: a cationic polymeric space-charge electret material with antiviral properties bonded to a hydrophobic substrate material, wherein the cationic polymer is natural, semi-synthetic, or synthetic; further wherein the cationic polymer has a linear, branched, hyper-branched or dendrimer-like structure and the cationic polymer comprises at least cationic bearing group located in the backbone or side chain of the cationic polymer; and wherein the hydrophobic material has a surface that is positively charged in a uniform manner.
2. The antiviral material of claim 1, wherein the cationic polymer is selected from the group of PEI, linear polyethylenimine, branched polyethylenimine, gelatin, chitosan, cationic peptides, cationic cyclodextrin, cationic dextran, cationic cellulose, polylysine, polyamidonamine, poly(amino-co-ester)s, or poly[2-(N,N-dimethylamino)ethyl methacrylate]polyethylenimine.
3. The antiviral material of claim 2, wherein the cationic polymer is polyethylenimine.
4. The antiviral material of claim 3, wherein the space-charge electret material comprises 0.195%-10% polyethylenimine cationic polymer.
5. The antiviral material of claim 4, wherein the space-charge electret material comprises substantially 2%-8% polyethylenimine cationic polymer.
6. The hydrophobic material of claim 1, wherein the hydrophobic substrate material is one or more of a cotton-polyester blend, cotton, polyester, a cellulose-polyester blend, cellulose, spunlace, polypropylene (PP), polylactic acid (PLA), polyethylene (PE), polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), poly(methyl methacrylate) (PMMA), polytetrafluroehtylene (PTFE), silicone, latex, nylon, or glass.
7. The hydrophobic material of claim 5, wherein the hydrophobic substrate material is one or more of a cotton-polyester blend, cotton, polyester, cellulose, polypropylene, polyethylene, or spunlace.
8. The antiviral material of claim 1, wherein the material has a minimum average positive surface charge of 2-35 nC cm.sup.−2.
9. The antiviral material of claim 1, wherein the material retains antiviral efficacy upon weaving, bonding, blending or mixture in a volume with other, non-antiviral materials.
10. The antiviral material of claim 1, wherein the material is formed as a porous sheet, membrane, woven fabric or nonwoven fabric.
11. A method of manufacturing an antiviral material, comprising: dissolving a space-charge electret material in a suitable solvent to form a space-charge electret material/solvent mixture, wherein the concentration of the space-charge electret material in the solvent is 0.195%-10%; applying the space-charge electret material/solvent mixture to a hydrophobic substrate material by dip-coating and/or spraying to coat the hydrophobic substrate material; subjecting the resultant coated hydrophobic material to a tensioning process, wherein the tensioning process comprises one of more of steaming, heating, pressing, and/or subjecting to pressure; and washing the material to remove unbonded mixture components.
12. The method of claim 11, wherein the space-charge electret material is dissolved in a solvent with no added salt.
13. The method of claim 12, wherein the solvent is water.
14. The method of claim 11, wherein the space-charge electret material is 0.195%-10% polyethylenimine.
15. The method of claim 14, wherein the space-charge electret material is substantially 2%-8% polyethylenimine.
16. The method of claim 11, wherein the space-charge electret material/solvent mixture is spread uniformly upon the hydrophobic substrate material to form a polymer-soaked substrate material, further wherein the polymer-soaked substrate is heated at 50-160 degrees celsius for at least 5 seconds.
17. The method of claim 11, wherein the hydrophobic substrate material is one or more of a cotton-polyester blend, cotton, polyester, a cellulose-polyester blend, cellulose, spunlace, polypropylene (PP), polyactic acid (PLA), polyethylene (PE), polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), poly(methyl methacrylate) (PMMA), polytetrafluoroethylene (PTFE), silicone, latex, nylon, or glass.
18. The method of claim 17, wherein the hydrophobic substrate material is one or more of a cotton-polyester blend, cotton, polyester, cellulose, or spunlace.
19. The method of claim 11, wherein the resultant coated hydrophobic material has a minimum average positive surface charge of 2-35 nC cm.sup.−2.
20. The method of claim 11, wherein the material is formed as a porous sheet, membrane, woven fabric or nonwoven fabric.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE INVENTION
[0059] The present application is described in detail below in conjunction with figures and specific embodiments to enable a person of ordinary skill in the art to make and use the various embodiments. Descriptions of specific devices, techniques, and applications are provided as examples. Various modifications to the examples described herein will be readily apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other examples and applications without departing from the spirit and scope of the present invention. Thus, the disclosed invention is not intended to be limited to the examples described herein and is to be accorded the full breadth and scope consistent with the claims.
Definitions
[0060] Unless defined otherwise, all technical and scientific terms used herein have the same plain meanings as commonly understood by one of ordinary skill in the art of the present application. The terms used in the description of the present application are for the purpose of describing or explaining particular embodiments only and are not intended to be limiting the present application. As used herein, the term “and/or” comprises any and all combinations of one or more of the associated listed items.
[0061] Furthermore, the technical features referred to in various embodiments of the present application described below may be combined with each other as long as they do not contradict or conflict with each other.
[0062] As used herein, an “electret” (the word is formed of electr- from “electricity” and -et from “magnet”) refers to a dielectric material that has a quasi-permanent macroscopic electrical field at its surface. It can be divided into two distinct classes of materials: dipolar electret and space-charge electret. Dipolar electrets consist of electric dipoles that are typically otherwise overall electrically neutral, but can lead to a quasi-permanent electric field macroscopically after the alignment of dipoles by external forces (such as via high-voltage polarization). The materials that have a net macroscopic electrostatic charge are defined as space-charge electrets, which can be easily generated by contact electrification. They possess quasi-permanent electrical field upon their surfaces owing to the imbalance of charge. Electrets can be made by first melting a suitable dielectric material, such as a polymer or wax that contains polar molecules, and then allowing it to re-solidify in a powerful electrostatic field. The polar molecules of the dielectric align themselves to the direction of the electrostatic field, producing a dipole electret with a permanent electrostatic bias. Any factors disrupting the alignment of polar molecules will result in the decrease of electrostatic field, such as high temperature. Electrets can also be made by embedding excess charges into a highly insulating dielectric, e.g., by means of an electron beam, corona discharge, injection from an electron gun, electric breakdown across a gap, or via a dielectric barrier.
[0063] The present space-charge electret materials with antibacterial, antiviral, bactericidal and virucidal effects possess high positive charge density, amphipathicity, and biocompatibility. In some embodiments, the space-charge electret materials comprise one or more cationic polymers. In certain preferred embodiments, the space-charge electret materials comprising one or more cationic polymers comprise (C-POLAR) linear polyethylenimine (PEI) and/or branched polyethylenimine (BPEI). In some embodiments, the space-charge electret materials do not align molecular poles or embed excess charges. In some embodiments, the space-charge electret materials or cationic polymers have a net electrostatic charge owing to the difference in the number of cationic and anionic charges. In some embodiments, the electric field of the space-charge electret materials can be further enhanced by contact electrification because of the easy transfer of ion groups. In other embodiments, the space-charge electret materials possess amphipathicity. In some embodiments, the space-charge electret materials possess hydrophilic cationic bearing groups and long hydrophobic alkyl chains.
[0064] As used herein, the term “space-charge density” or “charge density” refers to the amount of electrical charge per unit surface area or unit contact area. The term “positive space-charge density” or “positive charge density” refers to the total amount of positive charges minus negative charges per unit surface area or unit contact area.
[0065] As used herein, the term “conductivity” or “electrical conductivity” refers to a material's ability to resist electric current. In some embodiments, conductivity increases at low frequency. In some embodiments, conductivity decreases at high frequency.
[0066] As used herein, the term “resistivity” or “electrical resistivity” refers to a material's ability to conduct electrical current. It is the reciprocal of conductivity or electrical conductivity of the material.
[0067] As used herein, the term “surface energy” refers to the excess energy associated with the presence of a surface.
[0068] As used herein, the term “hydrophobic material” refers to a material comprising at least one hydroxyl group at the surface that can react with an amino group. The hydroxyl group can be part of the molecular structure itself (such as in the case of polyvinyl alcohol and its derivative copolymers), or the hydroxyl groups can come from water molecules adsorbed on the surface of the material, due to, for example, atmospheric moisture. Most surfaces, regardless of their inherent hydrophobicity, have a thin film of water deposited on their surfaces. Even hydrophobic materials with solid surface energy less than 20 Nm m.sup.−1 (such as PTFE and poly(tetrafluoroethylene-cohexafluoropropylene) (FEP)) can adsorb around 1.5-2.0 monolayers of water on their surfaces. In some embodiments, the hydrophobic material is a synthetic polymer. In some embodiments, the hydrophobic material is a synthetic polymer that possesses at least one hydroxyl group. In some embodiments, the synthetic polymer has a more hydrophobic surface and contains less hydroxyl groups. In some embodiments, the synthetic polymer has a solid surface energy between 28 and 48 mN m.sup.−1.
[0069] In some embodiments, the amino group is part of a silyl-linker of the present disclosure. Hydrophobicity can be measured by methods known to one of skill in the art, such as measuring the contact angle of liquid droplets on the surface of a material or calculating the solid surface energy. In some embodiments, the hydrophobic material is a synthetic polymer or a natural polymer. Examples of synthetic polymers include, but are not limited to, polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET). In some embodiments the hydrophobic material includes natural polymer cellulose fibers or fabrics that contain hydroxyl groups. In some embodiments, the hydrophobic material is a mixture of synthetic and natural polymers having a suitable surface wettability. The surface wettability of substrates can be adjusted by blending synthetic and natural polymer fibers. Examples of hydrophobic materials include, but are not limited to cotton, linen, silk, wool, spunlace, chitosan, polyvinyl alcohol, polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polyethyle terephthalate (PET), acrylonitrile butadiene styrene (ABS), poly(methyl methacrylate) (PMMA), aramids (such as nylon), silicone (such as polydimethylsiloxane), latex, glass, semifluorinated polymers and perfluorinated polymers (such as polytetrafluoroethylene (PTFE)). In other embodiments, the hydrophobic material is polyester. “Polyester” is a polymer that contains an ester functional group in every repeat unit of its main chain. Examples include, but are not limited to, polyethylene terephthalate (PET) and polybutylene terephthalate (PBT).
[0070] In some embodiments, the hydrophobic material is drawn with one or more hydroxyl groups as shown below. In some embodiments, the hydrophobic material is a fiber substrate material. A fiber substrate material is any material comprising cellulose fibers.
##STR00001##
[0071] One of skill in the art would understand that the above schematic drawing is not meant to indicate that the hydrophobic material/fiber substrate only has three —OH groups. Instead the drawing is merely illustrative and is meant to encompass many —OH groups, the number depending on the nature of the material.
[0072] As used herein, the term “C-POLAR” or “c-polar” refers to a positively charged/cationic polymer that can be applied to a hydrophobic material's surface, e.g., spunlace surface, cotton surface, or polyester surface. In some embodiments, “C-POLAR” or “c-polar” refers to electret materials (agents or solutions) used in the surface modification of textile substrates. In some embodiments, “C-POLAR” or “c-polar” is polyethylenimine (PEI); in some embodiments, “C-POLAR” or “c-polar” is linear polyethylenimine. In some embodiments, “C-POLAR” or “c-polar” is branched polyethylenimine (BPEI). In some embodiments, “C-POLAR” or “c-polar” refers to a range of concentrations of PEI or BPEI. In some embodiments, “C-POLAR” or “c-polar” is 2-30% PEI or BPEI, 2-15% PEI or BPEI, 2-10% PEI or BPEI, 2-8% PEI or BPEI, 2-4% PEI or BPEI, 4-6% PEI or BPEI, 6-8% PEI or BPEI, 2%, 3%, 4,%, 5%, 6%, 7%, or 8% PEI or BPEI. In some embodiments, “C-POLAR” or “c-polar” is 2%, 4%, 6%, 8%, or 10% PEI or BPEI. In some embodiments, “C-POLAR” or “c-polar” is a space-charged electret material. For the sake of clarity, “C-POLAR” or “c-polar” when described together with a textile, such as “C-POLAR spunlace” refers to a composition comprising a cationic polymer and a textile.
[0073] As used herein and in the claims, the term “antimicrobial composition” means a composition that is effective (i.e., is in a suitable form and amount) to kill microorganisms or inhibit their growth. In some embodiments, the antimicrobial composition is one or more space-charge electret materials. In some embodiments, the antimicrobial composition is one or more cationic polymers. In some embodiments, the antimicrobial composition comprises C-POLAR or BPEI. In some embodiments, the antimicrobial composition comprises cotton and/or polyester.
[0074] As used herein and in the claims, the terms “comprising” (or any related form such as “comprise” and “comprises”), “including” (or any related forms such as “include” or “includes”) “containing” (or any related forms such as “contain” or “contains”), means including the following elements but not excluding others. It shall be understood that for every embodiment in which the term “comprising” (or any related form such as “comprise” and “comprises”), “including” (or any related forms such as “include” or “includes”), or “containing” (or any related forms such as “contain” or “contains”) is used, this disclosure/application also includes alternate embodiments where the term “comprising”, “including,” or “containing,” is replaced with “consisting essentially of” or “consisting of”. These alternate embodiments that use “consisting of” or “consisting essentially of” are understood to be narrower embodiments of the “comprising”, “including,” or “containing,” embodiments.
[0075] As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Where a range is referred in the specification, the range is understood to include each discrete point within the range. For example, 1-7 means 1, 2, 3, 4, 5, 6, and 7.
[0076] As used herein, the term “about” is understood as within a range of normal tolerance in the art and not more than ±10% of a stated value. By way of example only, about 50 means from 45 to 55 including all values in between. As used herein, the phrase “about” a specific value also includes the specific value, for example, about 50 includes 50.
[0077] As used herein, the term “cationic polymer” refers to a macromolecule with cationic groups in the polymer backbone and/or in the side chains, such as cationic peptides, (quaternary) ammonium salts, biguanidines, phosphonium salts, guanidines, sulfonium, and pyridinium salts. In some embodiments, cationic polymers bear positive charges macroscopically and lead to a permanent, macroscopic electric field at their surfaces. In some embodiments, cationic polymers are a kind of space-charge electret material. In particular preferred embodiments, the cationic polymers comprise (C-POLAR) linear polyethylenimine (PEI) and/or branched polyethylenimine (BPEI).
[0078] As used herein, the term “amphipathicity” refers to the condition of a molecule having both a hydrophilic and hydrophobic regions, such as (in the case of cationic polymers), hydrophilic cationic bearing groups and long hydrophobic alkyl chains.
Antimicrobial Compositions
[0079] One embodiment of the present disclosure provides an antimicrobial composition comprising a space-charge electret material having
a positive surface charge density of 2-35 nC cm.sup.−2;
a conductivity less than 6×10.sup.−7 s m.sup.−1 within the frequency of 80 kHz; and
a hydrophobic material having a surface energy less than 50 mN m.sup.−1 or mJ m.sup.−2.
[0080] In some embodiments, the positive surface charge density is 5-10, 10-20, greater than 5.5, or greater than 9.59 nC cm.sup.−2.
[0081] In some embodiments, the space-charge electret material has a resistivity larger than 1.67×10.sup.6 Ω.Math.m.
[0082] According to another embodiment of the present disclosure, the space-charge electret material is a cationic polymer. In some embodiments, the cationic polymer is natural, semi-synthetic, or synthetic; the cationic polymer has a structure that is linear, branched, hyper-branched or dendrimer-like; and the cationic polymer comprises at least one cationic bearing group that is located in the backbone or the side chain of the polymer. In other embodiments, the cationic polymer is selected from the group consisting of gelatin, chitosan, cationic peptides, cationic cyclodextrin, cationic dextran, cationic cellulose, polyethylenimine (including linear polyethylenimine and/or branched polyethylenimine), polylysine, polyamidoamine, poly(amino-co-ester)s and poly[2-(N,N-dimethylamino)ethyl methacrylate]. In yet other embodiments, the polymer is selected from those listed in
[0083] According to another aspect of the present disclosure, the hydrophobic material's surface comprises cellulose structure having at least two components, and at least one of the components is slightly positively charged in polarity. In some embodiments, at least one of the at least two components has a surface energy less than 50 mN m.sup.−1. In some embodiments, the hydrophobic material's surface is highly dense, flat, even, and uniformly positively charged.
Linkers
[0084] In some embodiments, the cationic polymer is bonded to the hydrophobic material via a linker molecule. In some embodiments, the linker is a C.sub.1-C.sub.20 aliphatic chain wherein 0, 1, 2, or 3 carbon units of the C.sub.1-C.sub.20 aliphatic chain are replaced with one or more heteroatoms selected from the group consisting of —O—, —S—, and —NR—; R is independently H or C.sub.1-C.sub.6 alkyl; and at least one carbon unit of the C.sub.1-C.sub.20 aliphatic chain is bonded to a silyl group. In some embodiments, the silyl group is —Si(OR.sup.+).sub.2, —Si(R.sup.+).sub.2, or —Si(R.sup.+)(OR.sup.+); wherein each R.sup.+ is independently selected from the group consisting of H and C.sub.1-C.sub.6 alkyl; or R.sup.+ is the silyl group of another linker, wherein the silyl groups of two different linkers are joined together via a single —O— group. In some embodiments, R.sup.+ is independently H or C.sub.1-C.sub.3 alkyl.
[0085] By way of example, the illustration below shows how three silyl-linkers are bonded to the hydrophobic material and to each other via single —O— linkers.
##STR00002##
Si—C Linkers
[0086] According to another aspect, the silyl group is bonded to a carbon atom of the linker. In some embodiments, the carbon atom is an end carbon unit of the linker. An end carbon unit is a carbon unit of the aliphatic chain that is only bonded to one other unit in the aliphatic chain. For example, in a C.sub.4 carbon chain, CH.sub.3CH.sub.2CH.sub.2CH.sub.3, the end carbon units would be the first and fourth carbon atoms.
Si—N Linkers
[0087] In some embodiments, the silyl group is bonded to a nitrogen atom of the linker. In some embodiments, the linker is a C.sub.7-C.sub.20 aliphatic group wherein 1, 2, or 3 carbon units of the linker are replaced with —NR—, —N═, or —N(R).sub.2 wherein each R is independently H or C.sub.1-C.sub.6 alkyl.
[0088] One of skill in the art would understand which nitrogen group would be an appropriate replacement for a carbon group based on the number of valence groups in the carbon group that is being replaced. For example, in the aliphatic group CH.sub.3CH.sub.2CH.sub.═CHCH .sub.2CH.sub.3, the first carbon atom would be replaced by —N(R).sub.2, the second carbon atom would be replaced by —NR—, while the third carbon atom would be replaced by —N═.
[0089] In some embodiments, the linker, together with the cationic polymer is
##STR00003##
wherein R.sup.0 is CH.sub.3, CH.sub.2CH.sub.3, CH.sub.2CH.sub.2CH.sub.3, CH(CH.sub.3).sub.2; and n is 0, 1, 2, 3, or 4.
In some embodiments, n is >0. In some embodiments, n is 1, 2, 3, 4, 5, 6, 7, or 8. In some embodiments, n is >0 and <100. In some embodiments, n is 0-10, 0-20, 0-30, 0-40, or 0-50. In some embodiments, n is 1-20.
Linker+ Cationic Polymer Examples
[0090] Additional example embodiments of the linker together with the cationic polymer include
##STR00004##
Other Linkers
[0091] According to another aspect, the linker is a C.sub.7-C.sub.10 aliphatic wherein one of the carbon units of the linker is replaced with —O—. In some embodiments, the linker is optionally substituted with one or more J groups, wherein J is OR.sup.0, SR.sup.0, or N(R.sup.0).sub.2, wherein R.sup.0 is H or C.sub.1-C.sub.6 alkyl. In certain example embodiments, the linker is —Si(OR.sup.+).sub.2-(CH.sub.2).sub.3OCH.sub.2CH(OR.sup.0)CH.sub.2—.
[0092] In other example embodiments, the linker is —Si(OR.sup.+).sub.2. In yet other example embodiments, the silyl group is covalently bonded to a hydroxyl group of the hydrophobic material.
Processes of Modifying Hydrophobic Material Surfaces
[0093] Another aspect of the present disclosure provides a process of modifying the hydrophobic material's surface with the space-charge electret material, comprising the following steps:
(a) dissolving the space-charge electret material in a suitable solvent;
(b) introducing a mixture of the space-charge electret material/suitable solvent on the hydrophobic material's surface by dip coating and/or spraying;
(c) removing the suitable solvent by a tensioning process and/or drying in air or at a drying temperature; and
(d) optionally performing one or more systematic tests and evaluations on the hydrophobic material's surface by contact electrification performance evaluation, antiviral test, antibacterial test, virus filtration test and/or bacteria filtration test.
[0094] Another aspect of preferred embodiments of the present disclosure is a process of modifying a surface of the hydrophobic material, comprising the following steps:
(a) dissolving the space-charge electret material in a suitable solvent to form a space-charge electret material/suitable solvent mixture;
(b) introducing the space-charge electret material/suitable solvent mixture on the hydrophobic material's surface by dip coating and/or spraying;
(c) subjecting the hydrophobic material to a tensioning process and/or drying the material in air temperature or at a high drying temperature; and
(d) optionally performing one or more systematic tests and evaluations on the hydrophobic material's surface by contact electrification performance evaluation, antiviral test, antibacterial test, virus filtration test, and/or bacteria filtration test.
[0095] In some embodiments, the space-charge electret material is branched polyethylenimine (BPEI), linear polyethylenimine (LPEI or PEI), dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, cationic cellulose, didecyldimethylammonium chloride or a combination thereof.
[0096] In some embodiments, the space-charge electret material is LEI or BPEI.
[0097] In some embodiments, a concentration of the space-charge electret material in the suitable solvent is 0.195%-10%.
[0098] In some embodiments, the suitable solvent is water, ethanol or a mixture thereof. In some embodiments, the suitable solvent is water. In select preferred embodiments, the space-charge electret material is dissolved in a solvent with no added salt. In some embodiments, the hydrophobic material is cellulose or cellulose/polyester nonwoven fabrics.
[0099] In some embodiments, a tensioning process is applied, wherein the tensioning process includes one or more actions of stretching, steaming, heating, pressing, or subjecting the material to pressure, including high airflow pressure or mechanical pressure. In some preferred embodiments, pressure is applied to the material by adjustable rollers. In some preferred embodiments, heating is provided by an oven.
[0100] In some embodiments, the drying temperature is less than 100° C. In some embodiments, the drying temperature is 50° C.-100° C., 100° C.-200° C., 150° C.-200° C., 150° C.-175° C., 175° C.-200° C., 150° C.-170° C., or 155° C.-165° C. In some preferred embodiments, the drying temperature is 160° C.
[0101] In some embodiments, the one or more systematic tests and evaluations is/are contact electrification performance evaluation, antiviral test, antibacterial test, virus filtration test, bacteria filtration test or a combination thereof.
Process of Loading Space-Charge Electret Material
[0102] Another aspect of the present disclosure provides a process of loading the space-charge electret material onto a surface of the hydrophobic material, comprising the following steps:
(a) carding at least one of the at least two components to form a drylaid web;
(b) loading the space-charge electret material onto a fabric surface of the drylaid web by high-pressure liquid stream; and
(c) drying and winding up the drylaid web such that the space-charge electret material forms crosslinkers with the fabric surface to form the hydrophobic material's surface.
[0103] In some embodiments, the hydrophobic material comprises textile fibers that are knitted, woven, nonwoven, or a mixture thereof. In some embodiments, the textile fibers comprise both hydrophilic natural fibers and hydrophobic synthetic fibers (e.g., blended fibers). In some embodiments, the textile fibers comprise cotton, wool, cellulose, spunlace, synthetic polyester, polypropylene, polyethylene, nylon or a blend of at least two thereof. In some embodiments, the at least one of the components is cotton or polyester. In some embodiments, the other component is cotton or polyester, provided the two components are not identical. In some embodiments, the ratio of the two components is 65% polyester/35% cotton or 50% polyester/50% cotton.
[0104] In some embodiments, the cationic polymer comprises 0.195%-15% by weight of the total antimicrobial composition.
Processes for Preparing Linker Compositions
[0105] Some embodiments of the disclosure provide a process of preparing an antimicrobial composition having a linker molecule comprising the following steps:
a) mixing a silylated epoxide compound IIa with a hydrolysis agent in the presence of water to form compound IIb;
##STR00005##
[0106] wherein each R is independently C.sub.1-C.sub.6 alkyl;
b) heating compound IIb with hydrophobic material IIc to form compound IId;
##STR00006##
c) combining compound IId with a cationic polymer IIe under epoxide ring-opening conditions;
##STR00007##
[0107] to form an antimicrobial composition of Formula II or II′:
##STR00008## [0108] wherein
[0109] each R is independently H or C.sub.1-C.sub.6 alkyl; or R is the silyl group of another linker; and RX is H or is another linker.
[0110] In some embodiments, the another linker is formed via an epoxide ring-opening reaction. In some embodiments, the multiple linkers are attached as shown in the drawing below:
##STR00009##
[0111] Hydrolysis agents are known to one of skill in the art and may include acids or bases. For the sake of clarity, an acid is a molecule that can donate a proton. Examples include hydrochloric acid (HCl), hydroiodic acid (HI), hydrobromic acid (HBr), perchloric acid (HClO.sub.4), nitric acid (HNO.sub.3) and sulfuric acid (H.sub.2SO.sub.4). In some embodiments, acids together with water are capable of hydrolysing a molecule, i.e., displacing other groups with water molecules. Other embodiments wherein the hydrolysis agent is an acid or a base; weak acid or a weak base; defined as above, also provide examples and ranges from below.
[0112] In some embodiments, the hydrolysis agent is “pH-adjusted” water. The water's pH can be adjusted by adding a weak acid (such as acetic acid) or a weak base (such as ammonia) to effect the hydrolysis of IIa to IIb. In some embodiments, the concentration range of acetic acid in water is 0.02%-1%. In other embodiments, the concentration of ammonia is between 0.25-3%. In some embodiments, the hydrolysis reaction is done at a temperature of below 50° C., in some embodiments, from 20-50° C.
[0113] Epoxide ring-opening conditions are known to one of skill in the art and typically involve the use of Lewis acids, such as trimethylborane, aluminum oxide and lithium perchlorate. In some embodiments, at least one Lewis acid is added and used as catalyst to activate the ring opening of the epoxide by an amino group of another molecule. In some embodiments, the epoxide ring opening reaction is done at a temperature of 60° C.-150° C. for a duration ranging from 5 minutes to 3 hours. One of skill in the art would know that in some embodiments, the epoxide ring-opening reactions can be conducted without a Lewis acid. For example, in some embodiments, microwave irradiation is used for post-treatment to increase the grafting ratio of linear/branched polyethylenimine onto the surface of modified substrate containing epoxy groups.
[0114] Examples of compound of formula IIa are shown below:
TABLE-US-00001 Compound name Structure IIa-1 3-Glycidyloxypropyltrimethoxysilane
[0115] The cationic polymers described herein contain many amino groups, and the hydrophobic material treated with the epoxy-silyl linkers (compounds of formula IId) also include several reactive epoxy sites. As such, there are multiple ways in which the amino groups of the cationic polymer can react with the hydrophobic material through the linkers described herein via one or more epoxide ring-opening reactions. Sometimes, two amino groups in the same polymeric repeating unit of the cationic polymer can react with epoxide groups on two different silyl linkers and thus bond to two different hydroxyl groups of the hydrophobic material, as shown in the schematic below.
##STR00012##
[0116] One of skill in the art would understand that there are multiple ways in which the amino groups of the cationic polymer can react with the various epoxide groups in the compounds of formula IId.
[0117] Another embodiment of the present invention provides a process of preparing an antimicrobial composition having a linker comprising the following steps: [0118] d) hydrolysing compound IIIa in the presence of water and acid to form compound IIIb;
##STR00013## [0119] wherein R is an aliphatic group; [0120] e) heating hydrolysed compound IIIb with a hydrophobic material IIIc:
##STR00014## [0121] to form an antimicrobial composition of Formula III:
##STR00015## [0122] wherein L.sup.1 and L.sup.2 are each independently H or a silyl group of another linker that is bonded to the same hydrophobic material.
[0123] In some embodiments the compound of IIIa is
##STR00016## [0124] wherein R═CH.sub.3, CH.sub.2CH.sub.3, CH.sub.2CH.sub.2CH.sub.3, CH(CH.sub.3).sub.2; n is 0, 1, 2, 3, or 4.
[0125] In some embodiments, the compound of IIIa is selected from a compound in Table IIIa.
TABLE-US-00002 TABLE IIIa Structure Name
[0126] In some embodiments, the hydrophobic material IIIc comprises multiple hydroxyl (OH) units, and thus there are multiple ways in which hydrolyzed compound IIIb could react with the hydroxyl groups. In some example embodiments, one or more silyl groups could bond which each other through an oxygen atom, as shown in the schematic below.
##STR00023##
[0127] Another aspect of the disclosure provides a process of preparing an antimicrobial composition having a linker comprising the following steps: [0128] a) reacting cationic polymer IVa
##STR00024## [0129] with a silylation agent Z—Cl, wherein [0130] Z is SiR(OR).sub.2, Si(R).sub.2(OR), or Si(OR).sub.3; and [0131] each R is independently C.sub.1-C.sub.6 alkyl; [0132] to form compound IVb; wherein compound IVb is
##STR00025## [0133] each R is independently C.sub.1-C.sub.6 alkyl; [0134] b) mixing compound IVb with acid in the presence of water to form compound IVc; wherein compounds IVc is
##STR00026## [0135] each R is independently C.sub.1-C.sub.6 alkyl; [0136] c) heating compound IVc with a hydrophobic material IVc
##STR00027## [0137] to form the antimicrobial composition of formula IV:
##STR00028##
[0138] Another aspect of the disclosure provides a process of preparing an antimicrobial composition having a linker comprising the following steps:
a) reacting cationic polymer Va
##STR00029##
[0139] with a silylation agent Z—Cl, wherein [0140] Z is SiR(OR).sub.2, Si(R).sub.2(OR), or Si(OR).sub.3; and [0141] each R is independently C.sub.1-C6 alkyl;
[0142] to form compound Vb; [0143] wherein compound Vb is a compound of formula Va wherein one or more nitrogen units is silylated with one or two Z groups;
[0144] b) mixing compound Vb with acid in the presence of water to form compound Vc; wherein compound Vc is a compound of Vb wherein R is H;
[0145] c) heating compound Vc with a hydrophobic material Vd comprising at least one OH group;
##STR00030##
[0146] d) to form an antimicrobial composition of applicable claims hereto.
Silylation Agents
[0147] Silylation agents are known to one of skill in the art and are agents that aid in adding a Silyl group to another molecule. In some embodiments, the Silylation Agent is Z—Cl, wherein Z is SiR(OR)2, Si(R)2(OR), or Si(OR)3; and each R is independently C.sub.1-C.sub.6 alkyl;
[0148] In some embodiments each R is independently CH.sub.3, CH.sub.2CH.sub.3, CH.sub.2CH.sub.2CH.sub.3, or CH(CH.sub.3).sub.2.
[0149] Example embodiments of antimicrobial compositions having Si linkers are shown in Table V:
TABLE-US-00003 TABLE V
[0150] In some embodiments, compound IVb is selected from a compound of Table IV.
TABLE-US-00004 TABLE IV
wherein each R is independently C.sub.1-C.sub.6 alkyl.
Method of Killing Microbes
[0151] Another aspect of the present disclosure includes provision a method of killing microbes, comprising the steps of filtering air comprising microbes through the antimicrobial composition of the present disclosure to produce air that is 95% to 99.9% microbe-free. In some preferred embodiments, the air is 99-99.9% microbe-free. In some most preferred embodiments, the air is 99.9% microbe-free.
[0152] In some embodiments, the microbes have a mean particle size (MPS) of 1-10 μm. In some embodiments, the microbes have an MPS of 1-5 μm. In some embodiments, the microbes have an MPS of 3.0±0.3 μm.
[0153] In some embodiments, the air is moving through the antimicrobial space-charge electret material at an air flow rate of at least 20 L/min. In some embodiments, the air flow rate is 20-50 L/min. In some embodiments, the air flow rate is 28.3 L/min.
[0154] In some embodiments, the microbes are bacteria or viruses. In some embodiments, the virus is SARS-CoV-2, SARS-229E, Coxackievirus-B6, or influenza. In some embodiments, the bacteria is Staphylococcus aureus.
[0155] Another aspect of the present disclosure provides a method of killing microbes comprising the steps of contacting the space-charge electret material with a microbe for an incubation time of at least 1-5 minutes, thereby killing 99.9% of the microbe. In some embodiments, the microbe is bacteria and the incubation time is at least 1 minute. In some embodiments, the microbe is a virus and the incubation time is at least 5 minutes. In some embodiments, the virus is SARS-CoV-2, SARS-229E, Coxackievirus-B6, or influenza. In some embodiments, the bacteria is Staphylococcus aureus. For the sake of clarity, “contacting” means bringing the microbes within such proximity to the antimicrobial composition such that the high positive charge density of the space-charge electret material captures and kills the microorganism or microbe as described herein.
Method of Measuring Space-Charge Density
[0156] Another aspect of the present disclosure provides a method of measuring space-charge density on a testing material, comprising the steps of
(a) positioning the testing material between a bottom acrylic plate comprising an adhesive electrode layer and an upper acrylic plate comprising a reference material/electrode layer of a charge measurement device, and an electrometer is connected to the adhesive electrode layer and the reference material/electrode layer and the testing material is adhered to the adhesive electrode layer;
(b) contacting and separating the upper acrylic plate and the bottom acrylic plate repeatedly by a machine while repeatedly measuring the charge value by the electrometer to obtain one or more charge curves;
(c) calculating a charge value difference by subtracting the minimum charge value from the maximum charge value; and
(d) determining the space-charge density on the testing material by dividing the charge value difference by a contact area of the testing material between both the adhesive electrode layer and the reference material/electrode layer.
[0157] In some embodiments, the reference material is polytetrafluoroethylene (PTFE) film.
[0158] In some embodiments, the adhesive electrode and the reference material/electrode layer have identical size.
Antimicrobial Products
[0159] Another aspect of the present disclosure is the provision of antimicrobial products comprising and incorporating the antimicrobial compositions of any of the preceding embodiments. In some embodiments, the antimicrobial goods product is an air conditioning system, air conditioning unit, air purifier, disinfecting fabric, disinfecting garment (PPE), face mask, reusable disinfecting face mask, air filter, HEPA filter, HEPA filter for electric vehicles, automatic fabric, automotive interior material, disinfecting material, disinfecting clothing, disinfecting glove, or hand sanitizer.
[0160] In some embodiments, the two components of the surface of the hydrophobic material are cotton and cellulose; and the space-charge electret material comprises branched/linear polyethyleneimine, chitosan, poly-L-lysine or poly-D-lysine. In some embodiments, the cellulose is polyester; and the space-charge electret material comprises branched polyethylenimine (BPEI) or linear polyethylenimine. In some embodiments, the two components of the surface of the hydrophobic material are 50% cotton and 50% polyester; and the space-charge electret material comprises one or more of 2%, 3%, 4%, 5%, 6%, 7%, 8%, and 9% branched polyethylenimine (BPEI) or linear polyethylenimine. In some embodiments, the two components of the surface of the hydrophobic material are 50% cotton and 50% polyester; and the space-charge electret material comprises 8% branched polyethylenimine (BPEI) or 8% linear polyethylenimine (PEI). In some embodiments, the antimicrobial composition further comprising 8.7% poly(diallyldimethylammonium chloride), 19.7% polyacrylamide; and/or 3.1% ammonium polyphosphate.
EXEMPLARY EMBODIMENTS OF THE INVENTION
Methods of Killing Microbes
[0161] Referring to
Space-Charge Electret Materials
[0162] The space-charge electret material of the present disclosure is comprised of one or more cationic polymers. Referring to
[0163] Different cationic polymers have different positive charge density. Other embodiments provide compositions having a high positive charge density surface of space-charge electret materials to meet the specific requirements of target applications. Positive charge density plays a key role in the degree of antibacterial and antiviral activity for a textile substrate treated with space-charge electret materials. In select preferred embodiments, the space-charge electret materials bonded to a hydrophobic substrate material, such as a textile, features a uniform or substantially uniform positive charge density across the surface area of the material. In some embodiments, the space-charge electret material has a positive charge density of 9.59 nC cm.sup.−2. The disinfection effects increase with the increase of positive charge density.
Uses of Space-Charge Electret Materials
[0164] Space-charge electret materials can be applied and used in many ways for antibacterial, antiviral, bactericidal and virucidal applications.
[0165] Referring to
Methods of Making Antimicrobial Compositions
[0166] Referring to
[0167] Secondly, BPEI is introduced on a desired textile substrate material by either dip coating or spraying. Preferred textile substrate materials involve cellulose and cellulose/polyester nonwoven fabrics. Thirdly, textile substrate loaded with BPEI solution is required for the removal of solvent, which can be conducted by drying in air or by drying at a high temperature for quicker solvent evaporation. Preferably, the drying temperature shall be not over 100° C. Finally, textile substrate materials modified with BPEI space-charge electret (BPEI modified textiles) can be used for systematic tests and evaluation, such as contact electrification performance evaluation, antiviral tests, antibacterial tests, virus filtration tests, and bacteria filtration test.
Methods of Evaluating Contact Electrification Performance
[0168]
Space-Charge Electret Material Concentrations & Charge Density of Textile Substrates
[0169]
[0170] Different single-component space-charge electret materials have different positive charge density values. Some examples are shown in Table 1.
TABLE-US-00005 TABLE 1 The positive charge density of textile substrates treated with various single-component space-charge electret materials. Positive charge Space-charge electret material density (nC used to treat textile substrates cm.sup.−2) 6 wt. % dimethyloctadecyl [3-(trimethoxy- 3.25 silyl)propyl] ammonium chloride solution 6 wt. % cationic cellulose 9.91 6 wt. % didecyldimethylammonium chloride 0.37
[0171] Therefore, the positive charge density of textile substrates can be adjusted by adjusting the solution concentration and components of space-charge electret materials.
[0172] To obtain modified textiles with high positive charge density, single-component space-charge electret materials with high charge density and suitable concentration can be selected. To obtain modified textiles with suitable positive charge density and hydrophobicity, multiple-component space-charge electret materials can be selected based on different types of cationic polymers and components. The selection of cationic polymers with higher hydrophobicity can use polymers with low density cationic groups and long alkyl chains. In select preferred embodiments of the invention, the high positive charge density of the modified textiles is uniformly or substantially uniformly applied and obtained across the surface area of the textile.
[0173]
Antiviral Efficacy
[0174] Referring to
[0175] Referring to
[0176] Referring to
Antibacterial Efficacy
[0177] Referring to
TABLE-US-00006 TABLE 2 Material of the textile substrate for each sample no. in FIG. 13. Sample no. Material of Textile Space-charge shown in FIG. 13 Substrate electret material #1 50% cotton/50% polyester 2%-9% BPEI #2 50% cotton/50% polyester 2%-9% BPEI
TABLE-US-00007 TABLE 3 Material of the textile substrate for each sample no. in FIG. 14. Sample no. Material of Textile Space-charge shown in FIG. 14 Substrate electret material #1 100% cotton plain 2%-9% BPEI #2 100% cotton after 60 washes 2%-9% BPEI #3 polyester/cotton (65%/35%) 2%-9% BPEI #4 polyester/cotton (65%/35%) 2%-9% BPEI after 60 washes #5 polyester/spandex (92%/8%) 2%-9% BPEI #6 polyester/spandex (92%/8%) 2%-9% BPEI after 60 washes
[0178] Taken together, the results show that both 50% cotton/50% polyester and 35% cellulose/65% polyester textile treated with BPEI space-charge electret material killed Staphylococcus aureus with efficacy of over 99.9%. The antibacterial activity values of textile substrates after washing 60 times are greater than 3, indicating that 60 washes have little influences on the strong antibacterial activity of BPEI-treated cellulose/polyester textile material.
[0179] Referring to
Cytotoxicity
[0180] Referring to
[0181] Referring to
[0182] Referring to
[0183] Referring to
[0184] For the animal skin irritant tests, four healthy conventional New Zealand White Rabbits, female, 2.0-3.0 kg each were employed. The rabbits were kept at room temperature (18-23° C.) in relative humidity of 45-65%. The results in
[0185] For the skin sensitization tests, guinea pigs, female, 300-500 g each were employed. The guinea pigs were kept at room temperature (20-22° C.) in relative humidity of 45-65%. The results in
Process of Loading Space-Charge Electret Materials on Textile Substrate
[0186] Referring to
[0187] Referring to
Processes for Preparing Bonded Compositions
[0188]
[0189] In most preferred embodiments of the invention, a tensioning process step is applied to subject coated fiber substrate materials, wherein a “tensioning process” includes one or more of the acts of stretching, steaming, heating, pressing, or subjecting the material to pressure, including high airflow pressure or mechanical pressure. For example, a fiber substrate material can be drawn into a heating chamber with rollers and dried at a higher temperature, e.g., 160° C. It shall be understood that the force applied on the textile substrate material may be adjusted by the rollers. Furthermore, the drying time and temperature may also be adjusted. In some exemplary embodiments, the temperature is 100° C.-200° C., 150° C.-200° C., 150° C.-175° C., 175° C.-200° C., 150° C.-170° C., or 155° C.-165° C. In a most preferred embodiment, the temperature is 160° C.
[0190] The resultant PEI coated fiber substrate material may be confirmed by measuring the variation of grammage (grams per square meter), wherein a variation of 10% is considered acceptable.
[0191] The mass variation of PEI modified textile can be calculated by W=(m.sub.1-m.sub.0/m.sub.0*100%, wherein m.sub.1 is the grammage of PEI modified textile substrate material and m.sub.0 is the grammage of the pristine textile substrate material.
BRANCHED PEI: Select Exemplary Embodiment 1
[0192] In an exemplary embodiment, 60 g of branched PEI polymers (MW 20000) is dissolved in 940 ml of water at room temperature and stirred for at least 5 minutes to form a 6% branched PEI solution. A 0.30 mm thick 50% polyester 50% cotton cellulose fabric material is dipped in the 6% branched PEI solution for 2-10 seconds, or by spraying the fabric material with a shower spray within a shower chamber. Once fully wet, the fabric material undergoes a tensioning process wherein the PEI coated fabric is drawn into a heating chamber with rollers and is dried at 160° C. for at least 5-20 seconds. “Tensioning” may also include one or more actions of stretching, steaming, heating, pressing, and/or subjecting the material to pressure, including high airflow pressure or mechanical pressure. The resultant coated fabric material is characterized by grammage measurement and FT-IR attenuated total reflectance (ATR) spectroscopy. Anti-microbial properties may be confirmed via tests described herein.
BRANCHED PEI: Select Exemplary Embodiment II
[0193] In another exemplary embodiment, 40 g of branched PEI polymers (MW 25000) are dissolved in 960 ml of water at room temperature and stirred for at least 5 minutes to form a 6% branched PEI solution. A 0.30 mm thick 50% polyester/50% cotton cellulose fabric material is dipped in the 6% branched PEI solution, and then dried at 160° C. for 10 seconds. The resultant coated fabric material is characterized by grammage measurement and FT-IR attenuated total reflectance (ATR) spectroscopy.
[0194] The grammage of pristine 50% polyester/50% cotton cellulose fabric material is 35-75 g/m.sup.2. BPEI modified 50% polyester/50% cotton cellulose fabric material treated with 1%-6% BPEI solution according to the above-disclosed example has a mass variation W of between 10% and 70%.
LINEAR PEI: Select Exemplary Embodiment
[0195] In another preferred embodiment, 500 mg of linear PEI polymers are dissolved in 500 ml of water to form a homogeneous and clear solution. A 0.30 mm thick 50% polyester/50% cotton cellulose fabric material is used as substrate and soaked in linear PEI solution for 5 minutes and then taken out for air drying. In a most preferred embodiment, when the wet substrate no longer drips liquid under gravity conditions, it is transferred to an oven at 60° C. for expedited drying. The dried substrate is ironed at 160° C. on both sides. Finally, it is dried at 60° C. to obtain the linear PEI modified 50% polyester/50% cotton cellulose fabric material. The resultant coated fabric is characterized by grammage measurement and FT-IR attenuated total reflectance (ATR) spectroscopy.
[0196] The antimicrobial properties of the PEI and BPEI modified fabric may be confirmed via tests described herein.
[0197] Process for Preparing Si-Linker Compositions
[0198]
[0199] In an exemplary embodiment, 10 g of 3-glycidyloxypropyltrimethoxysilane (
[0200]
[0201]
[0202] In an exemplary embodiment, 20 g of 3-[2-(2-Aminoethylamino)ethylamino]propyl-trimethoxysilane is dissolved in 1000 mL water solution at room temperature to form a 2% silane solution. Then a fiber substrate, such as 0.30 mm thick 50% polyester 50% cellulose material, is soaked in the 2% silane aqueous solution. The solution is heated to 40° C. and held for 2 h. During this soaking process, methoxyl groups of 3-[2-(2-Aminoethylamino)ethylamino]propyl-trimethoxysilane react with water via hydrolysis to form silanol groups. It is chemically bonded on the fiber surface via dehydration/condensation reaction with the hydroxyl group of fiber. The 3-[2-(2-Aminoethylamino)ethylamino]propyl-trimethoxysilane can also first self-polymerize into oligomeric structures by silanol self-condensation reactions and then graft onto the fiber surface via —O— linkers. The modified fiber substrate is removed from the solution, taken out for draining water in the air, and transferred to an oven at 60° C. for 2 hours. After complete drying, it is washed with pure water to remove unattached compounds and re-dried at 60° C. for 2 hours to obtain textile/fiber substrate with surface modification of linear PEI molecules and oligomers.
[0203]
[0204] In an example embodiment, 500 mg of linear PEI polymers is dissolved in 200 mL of ethanol in a sealed vessel. The vessel is placed in an ice bath (0° C.) and nitrogen gas is bubbled into the solution for the removal of oxygen. Then 5 g chlorotriethoxysilane is slowly dripped into the solution over 30 minutes and continuously stirred for 1 hour in the N.sub.2-filled atmosphere at 0° C., followed by stirring at 40° C. for 2 hours. The solution is then poured into an excess amount of diethyl ether to obtain precipitation of the silylated linear PEI polymer, which is collected by filtration and further dried in a vacuum.
[0205] In another example embodiment, 10 g of branched PEI polymers is dissolved in 500 mL of ethanol in a sealed vessel. The vessel is placed in an ice bath (0° C.) and nitrogen gas is bubbled into the solution for the removal of oxygen. Then 20 g chlorotriethoxysilane is slowly dripped into the solution over 30 minutes and continuously stirred for 1 hour in the N.sub.2-filled atmosphere at 0° C., followed by stirring at 40° C. for 2 hours. Then 500 mL diethyl ether is poured into the solution, leading to liquid stratification. A separatory funnel is used to obtain the liquid layer containing the silylated branched PEI polymer. The final product is further dried in a vacuum and sealed storage unit.
[0206]
[0207] In another exemplary embodiment, 6 g of silylated branched PEI polymers is dissolved in 100 mL ethanol/water(50/50, w/w) mixture at room temperature. Then a fiber substrate, such as 0.30 mm thick 50% polyester 50% cellulose material, is soaked in the as-prepared solution for 30 minutes. The solution temperature is further increased to 40° C. and held for 2 h. During this soaking process, methoxyl groups react with water via hydrolysis to form silanol groups. It is chemically bonded on the fiber surface via dehydration/condensation reaction with the hydroxyl group of fiber. The modified fiber substrate is taken out for the draining of water in air and transferred to an oven at 60° C. for 2 hours. After complete drying, it is washed with pure water to remove unattached compounds and re-dried at 60° C. for 2 hours to obtain textile/fiber substrate with surface modification of silylated branched PEI polymers (formula 27D(iii)), which has a chemical bonding between the silyl groups of the silylated branched PEI polymers and the hydroxyl groups of the fiber substrate.
Methods of Designing and Manufacturing New Antimicrobial Compositions
[0208] Provided herein is a new disinfectant mechanism of space-charge electret material for capturing and killing microorganisms (such as bacteria and viruses) by synergistic effects of contact electrification, noncontact electrostatic interaction, and interface lipophilicity, to guide the design and fabrication of biocompatible space-charge electret materials with excellent antibacterial, antiviral, bactericidal and virucidal effects based on biocompatible cationic polymers and textile substrates. Space-charge electret materials shall possess both high positive charge density and suitable hydrophobicity to achieve excellent antibacterial, antiviral, bactericidal and virucidal effects. Positive charge density is demonstrated to play a key role on the degree of antibacterial and antiviral activity for a space-charge electret material.
[0209] Firstly, the space-charge electret material with high positive charge density attracts the biohazard (such as bacteria and viruses) with negatively charged protein via noncontact electrostatic interaction, leading to the increase of collision rate. Then contact electrification occurs when the drifting negatively-charged biohazard collides with the positively-charged electret, leading to a drastic change of electrostatic potential and sudden increase of electrical stress. The strong electrostatic field pins or traps the biohazard on the positively-charged surface tightly, and the generated inhomogeneous electric stress contributes to the shearing or tearing off the envelope protein and/or other key viral or microbial proteins of the biohazard. During the tight contact, the hydrophobicity of space-charge electret material helps its lipophilic partition insert into the biohazard membrane via Van der Waals interactions, contributing to the destruction of biohazards more easily and quickly. Through the proper choice of textile substrates with suitable structures, space-charge electret materials based on cationic polymer and textile substrates may have high viral and bacterial filtration efficacy. Such kinds of space-charge electret materials can be widely used for air filtering products (such as masks, protective garments, air filters and air purifiers), and personal/home sanitation and hygiene items, such as hand sanitizers, moist towelettes, and toilet papers, home/hotel textiles, and related hygienic disposable items.
Particular Exemplary Embodiments—Set 1
[0210] Provided herein is a new disinfectant mechanism of space-charge electret material for capturing and killing microorganisms (such as bacteria and virus) by synergistic effects of contact electrification, noncontact electrostatic interaction, and interface lipophilicity to guide the design and fabrication of biocompatible space-charge electret materials featuring excellent antibacterial, antiviral, bactericidal and virucidal effects based on biocompatible cationic polymers and textile substrates.
[0211] Positive charge density is demonstrated to play a key role on the degree of antibacterial and antiviral activity for a space-charge electret material.
[0212] Firstly, the space-charge electret material with high positive charge density attracts a target biohazard (such as bacteria and virus) with negatively charged protein via noncontact electrostatic interaction, leading to an increase in collision rate.
[0213] Then contact electrification occurs when the drifting negatively-charged biohazard collides with positively-charged electret, leading to a drastic change of electrostatic potential and sudden increase of electrical stress. The strong electrostatic field leads to the biohazard becoming pinned on the positive charge surface tightly, and the generated inhomogeneous electric stress contributes to the tearing or shearing off of the envelope protein and/or other key viral or microbial proteins of the targeted biohazard.
[0214] During the tight contact, the hydrophobicity of space-charge electret material helps its lipophilic partition insert into the biohazard membrane via Van der Walls interactions, contributing to the destruction of biohazards more readily and quickly.
[0215] Provided herein is a technical route of using one or more kinds of cationic polymers and hydrophilic fiber/hydrophobic blended textile substrates for the preparation of space-charge electret materials with high charge density and suitable surface hydrophobicity;
[0216] Provided herein is a new application of using space-charge electret materials for biocompatible disinfectant/sanitizers with excellent antibacterial, antiviral, bactericidal and virucidal effects;
[0217] Provided herein is a new application of using space-charge electret materials for air filters with high viral filtration efficacy and bacterial filtration efficacy;
[0218] To achieve excellent antibacterial, antiviral, bactericidal and virucidal effects as well as high viral/bacterial filtration efficiency, the positive charge density of textile substrates treated with cationic polymers is over 9.59 nC cm.sup.−2. In some embodiments, textile substrate consists of hydrophilic fiber (such as cellulose) and hydrophobic fibers (such as polyester).
[0219] Provided herein is a method and device for evaluating the contact electrification of space-charge electret materials.
[0220] Provided herein is a parameter of positive charge density for quantitative evaluation of the degree of contact electrification.
[0221] Provided herein is a device for measuring positive charge of a space-charge electret material is based on a double-layered device mainly consisted of a bottom acrylic plate fixed with a 6 cm×6 cm adhesive electrode layer and an upper acrylic plate fixed with an identical-size reference material/electrode layer. PTFE film is fixed as reference material. The testing samples can be woven/knitted/nonwoven fabric samples and films.
[0222] When testing, a sample (such as nonwoven textile substrate surface modified with space-charge electret material) is adhered to an adhesive electrode on the bottom acrylic plate smoothly and tightly. The upper acrylic plate can be controlled by machine to contact/impact the bottom acrylic plate repeatedly. This allows the contact between the surface of space-charge electret with the material-modified textile (modified with PTFE) surface by external pressure and enables their separation after the release of external pressure.
[0223] An electrometer is connected to the electrodes for real-time monitoring and measurement of the charge variation, and stable charge curves produced and measured over repeated contacts and separations are recorded for further analysis.
[0224] Generally, a maximum charge value appears during the contact state while a minimum charge value shows during the separation state. The value difference during the contact and separation states can be determined as positive charges generated by contact electrification. The positive charge density is calculated by using positive charges divided with the effective contact area (e.g., 6 cm×6 cm) for the quantitative evaluation of the degree of contact electrification.
[0225] While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of the invention. In addition, the various features, elements, and embodiments described herein may be claimed or combined in any combination or arrangement.