Multifunctional hierarchical material structure

Abstract

The composition comprises a hierarchically structured material and a plurality of nanoscale features disposed on at least a portion of a surface of the hierarchically structured material, the plurality of nanoscale features comprising a thorn-like morphology, and the hierarchically structured material is configured to treat a plurality of contaminants. In various embodiments, the hierarchically structured material comprises a material of natural origin or a material of synthetic origin.

Description

[Technical field]

[0001] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT This invention was made with Government support under Grant No. 2026128 awarded by the National Science Foundation. The Government has certain rights in this invention.

[0002] Related Applications This non-provisional application claims the benefit of priority to U.S. Provisional Application No. 63 / 287,717, filed December 9, 2021, entitled "Hierarchical Material Structure Having Mechano-Biocidal Properties for Pathogen Inactivation," and U.S. Provisional Application No. 63 / 316,853, filed March 4, 2022, entitled "Diatomaceous Earth Coated Filter Media With Renewal Function For Air Purification," the contents of both of which are incorporated by reference in their entireties herein.

[0003] The present disclosure relates to systems or compositions for treating pollutants, and more particularly to systems and compositions including hierarchical material structures or nanoscale features for treating pollutants. [Background technology]

[0004] Rationally designed, hierarchically structured materials with controlled discontinuities from the nanometer to the macroscale exhibit unprecedented mechanical, physical, and chemical properties. Such materials could lead to significant advances in many applications including optics, catalysis, semiconductors, energy storage, pollution mitigation, and many more. The ability to produce such complex (multiphase and nanostructured) materials may depend on developing methods to form microstructures with controlled compositions and morphologies in significant quantities. As materials become more complex in composition and their structural variations smaller, their preparation may become more complex and difficult to control, requiring advanced equipment and high energy inputs. Moreover, such materials may not be easily amenable to scale-up to enable large-scale applications. Moreover, in many cases, producing these materials may also produce toxic by-products. Summary of the Invention

[0005] Some embodiments relate to a composition comprising a hierarchically structured material and a plurality of nanoscale features disposed on at least a portion of a surface of the hierarchically structured material, the plurality of nanoscale features comprising a thorn-like morphology, and the hierarchically structured material configured to treat a plurality of contaminants.

[0006] Some embodiments relate to compositions in which the hierarchically structured material comprises materials of natural origin.

[0007] Some embodiments relate to a composition in which the naturally occurring hierarchically structured material comprises diatomaceous earth.

[0008] Some embodiments relate to compositions in which the hierarchically structured material comprises materials of synthetic origin.

[0009] Some embodiments relate to a composition wherein the plurality of contaminants comprises a pathogen, and the plurality of nanoscale features are configured to treat the pathogen.

[0010] Some embodiments relate to a composition in which the plurality of nanoscale features comprises a nanostructured coating.

[0011] Some embodiments relate to compositions in which the nanostructured coating exhibits catalytic functionality.

[0012] Some embodiments relate to compositions in which the nanostructured coating is configured to treat either gaseous or particulate contaminants.

[0013] Some embodiments relate to compositions in which the nanostructured coating is at least partially coated with a secondary coating.

[0014] Some embodiments relate to compositions in which the secondary coating comprises an inorganic material.

[0015] Some embodiments relate to compositions in which the secondary coating enhances catalytic, sorptive or biocidal functions.

[0016] Some embodiments relate to compositions in which the nanostructured coating exhibits sorptive functionality.

[0017] Some embodiments relate to compositions in which the nanostructured coating exhibits CO sorption and storage.

[0018] Some embodiments relate to compositions in which the hierarchically structured material comprises a plurality of particulates.

[0019] Some embodiments relate to compositions in which the plurality of microparticles have a size of from about 1 micron to about 50 microns.

[0020] Some embodiments relate to compositions in which the plurality of contaminant types are one or more of pathogens, particulates, and gas molecules.

[0021] Some embodiments relate to compositions in which the pathogen comprises one or more of a virus, a bacteria, and a fungus.

[0022] Some embodiments relate to compositions in which a plurality of contaminants is included in a fluid medium.

[0023] Some embodiments relate to compositions in which the flow medium comprises one or more of a gas or a liquid.

[0024] Some embodiments relate to compositions wherein the flow medium comprises an aqueous medium.

[0025] Some embodiments relate to compositions in which the flow medium comprises one or more bodily fluids.

[0026] Some embodiments relate to compositions in which the nanoscale features have a size between about 1 nm and about 30 nm.

[0027] Some embodiments relate to compositions in which the hierarchically structured material defines a plurality of interconnected pores, the interconnected pores having cross-sectional dimensions of from about 50 nm to about 10 microns.

[0028] Some embodiments relate to a composition in which a first composition of the hierarchically structured material is substantially the same as a second composition of the plurality of nanoscale features.

[0029] Some embodiments relate to a first composition of the hierarchically structured material that differs from a second composition of the plurality of nanoscale features.

[0030] Some embodiments relate to a system in which the composition of the plurality of nanoscale features comprises any of oxides, mixed oxides, transition metal oxides, zeolites, oxohydroxides, aluminates, silicates, aluminosilicates, titanates, oxometalates, vanadium, silica, ceria, alumina, titania, zirconia, nickel oxide, cobalt oxide, tin oxide, manganese oxide, magnesium oxide, precious metal oxides, platinum group metal oxides, molybdenum oxide, tungsten oxide, rhenium oxide, chromium oxide, rare earth oxides, and any combination thereof.

[0031] Some embodiments relate to compositions in which the material of synthetic origin comprises any of an oxide, mixed oxide, mixed oxide of one or more of Group I, II, III, IV, V, VI elements, zeolites, oxohydroxides, aluminates, silicates, aluminosilicates, titanates, oxometalates, metal organic frameworks, vanadium, silica, alumina, titania, zirconia, hafnia, nickel oxide, ceria, cobalt oxide, tin oxide, manganese oxide, magnesium oxide, precious metal oxides, platinum group metal oxides, molybdenum oxide, tungsten oxide, rhenium oxide, tantalum oxide, niobium oxide, chromium oxide, scandium, yttrium, lanthanum, thorium, rare earth oxides, and any combination thereof.

[0032] Some embodiments relate to compositions where the composition of nanoscale features comprises any of oxides, mixed oxides, transition metal oxides, zeolites, oxohydroxides, aluminates, silicates, aluminosilicates, titanates, oxometalates, vanadium, silica, alumina, titania, zirconia, nickel oxide, cobalt oxide, tin oxide, manganese oxide, magnesium oxide, precious metal oxides, platinum group metal oxides, molybdenum oxide, tungsten oxide, rhenium oxide, chromium oxide, rare earth oxides, and any combination thereof.

[0033] Some embodiments relate to compositions further comprising one or more active materials disposed on at least subset 1, including hierarchically structured materials of both natural and synthetic origin.

[0034] Some embodiments relate to compositions in which one or more active materials enhance the sorptive function.

[0035] Some embodiments relate to compositions in which one or more active materials enhance biocidal function.

[0036] Some embodiments relate to compositions in which one or more active materials enhance catalytic function.

[0037] Some embodiments relate to compositions in which the one or more compositions of the one or more active materials include one or more of catalytic nanoparticles, zeolites, MOFs, organic, inorganic, or polymers.

[0038] Some embodiments relate to a system comprising a macroscopically porous substrate defining a plurality of pores; and a composition deposited on an interior surface of at least some of the plurality of pores, the composition comprising a hierarchically structured material exhibiting surface nanostructured features.

[0039] Some embodiments relate to a system, wherein a composition comprises a hierarchically structured material and a plurality of nanoscale features disposed on at least a portion of a surface of the hierarchically structured material, the plurality of nanoscale features comprising a thorn-like morphology, and the hierarchically structured material is configured to treat a plurality of contaminants.

[0040] Some embodiments relate to a system in which the macroscopically porous substrate comprises a metal.

[0041] Some embodiments relate to a system in which the metal comprises an alloy.

[0042] Some embodiments relate to a system in which the macroscopically porous substrate comprises one or any combination of stainless steel, ferritic steel, iron-chromium alloy, austenitic steel, chromium-nickel alloy, copper, nickel, brass, gold, silver, titanium, tungsten, aluminum, palladium, and platinum.

[0043] Some embodiments relate to a system in which the composition forms a coating on the interior surfaces of at least some of the plurality of pores.

[0044] Some embodiments relate to systems in which the coating has a thickness of about 10 microns to about 100 microns.

[0045] Some embodiments relate to a system in which the coating is formed as a substantially continuous film.

[0046] Some embodiments relate to a system in which the coating is formed as a plurality of discontinuous segments.

[0047] Some embodiments relate to a system in which the plurality of pores has a size between about 100 nm and about 5 mm.

[0048] Some embodiments relate to a system in which the macroscopically porous substrate comprises a ceramic.

[0049] Some embodiments relate to a system in which the macroscopically porous substrate comprises a metal or metal alloy.

[0050] Some embodiments relate to a system in which the macroscopically porous substrate comprises a filter.

[0051] Some embodiments relate to a system in which the macroscopically porous substrate comprises a non-woven medium.

[0052] Some embodiments relate to a system in which the macroscopically porous substrate comprises a woven fabric medium.

[0053] Some embodiments relate to a system in which the macroscopically porous substrate comprises glass fibers.

[0054] Some embodiments relate to a system in which the macroscopically porous substrate comprises a ceramic.

[0055] Some embodiments relate to a system in which the ceramic comprises one or any combination of cordierite, mullite, zeolite, natural and synthetic clays.

[0056] Some embodiments relate to a system in which the macroscopically porous substrate is one or any combination of cellulose, natural rubber, latex, wool, cotton, silk, linen, hemp, flax, feather fibers, and any other natural material.

[0057] Some embodiments relate to a system in which the macroscopically porous substrate comprises any one or any combination of natural or synthetic fabrics and textiles.

[0058] Some embodiments relate to a system in which the macroscopically porous substrate comprises a particulate filter.

[0059] Some embodiments relate to a system in which the hierarchically structured material comprises naturally occurring materials.

[0060] Some embodiments relate to a system in which the naturally occurring hierarchically structured material comprises diatomaceous earth.

[0061] Some embodiments relate to systems in which the hierarchically structured materials include materials of synthetic origin.

[0062] Some embodiments relate to systems where the material of synthetic origin comprises any of an oxide, mixed oxide, mixed oxide of one or more of Group I, II, III, IV, V, VI elements, zeolites, oxohydroxides, aluminates, silicates, aluminosilicates, titanates, oxometalates, metal organic frameworks, vanadium, silica, alumina, titania, zirconia, hafnia, nickel oxide, cobalt oxide, cobalt oxide, tin oxide, manganese oxide, magnesium oxide, precious metal oxides, platinum group metal oxides, molybdenum oxide, tungsten oxide, rhenium oxide, tantalum oxide, niobium oxide, chromium oxide, scandium, yttrium, lanthanum, thorium, rare earth oxides, and any combination thereof.

[0063] Some embodiments relate to a system in which the plurality of contaminants includes a pathogen, and the plurality of nanoscale features are configured to treat the pathogen.

[0064] Some embodiments relate to a system in which the plurality of nanoscale features comprises a nanostructured coating.

[0065] Some embodiments relate to systems in which the nanostructured coating exhibits catalytic functionality.

[0066] Some embodiments relate to systems in which the nanostructured coating is configured to treat either gaseous or particulate contaminants.

[0067] Some embodiments relate to a system in which the nanostructured coating is at least partially coated with a secondary coating.

[0068] Some embodiments relate to systems in which the secondary coating comprises an inorganic material.

[0069] Some embodiments relate to a system in which the hierarchically structured material comprises a plurality of particulates.

[0070] Some embodiments relate to a system in which the plurality of microparticles has a size between about 1 micron and about 50 microns.

[0071] Some embodiments relate to systems in which the plurality of contaminant types are one or more of pathogens, particulates, and gas molecules.

[0072] Some embodiments relate to a system in which the pathogen comprises one or more of a virus, a bacteria, and a fungus.

[0073] Some embodiments relate to a system in which multiple contaminants are included in the flow medium.

[0074] Some embodiments relate to systems in which the flow medium comprises one or more of a gas or a liquid.

[0075] Some embodiments relate to a system in which the flow medium comprises an aqueous medium.

[0076] Some embodiments relate to a system in which the flow medium comprises one or more bodily fluids.

[0077] Some embodiments relate to systems in which the nanoscale features have a size between about 1 nm and about 30 nm.

[0078] Some embodiments relate to a system in which the hierarchically structured material defines a plurality of interconnected pores, the interconnected pores having cross-sectional dimensions of about 50 nm to about 10 microns.

[0079] Some embodiments relate to a system in which a first composition of the hierarchically structured material is substantially the same as a second composition of the plurality of nanoscale features.

[0080] Some embodiments relate to a system in which a first composition of the hierarchically structured material differs from a second composition of the plurality of nanoscale features.

[0081] Some embodiments relate to a system that includes a macroscopically porous substrate defining a plurality of pores and a plurality of nanoscale features disposed on at least a portion of an interior wall of the plurality of pores, the plurality of nanoscale features including a thorn-like morphology, the plurality of nanoscale features configured to treat a plurality of contaminants.

[0082] Some embodiments relate to a system further including one or more active materials disposed on at least a subset of the plurality of nanoscale features.

[0083] Some embodiments relate to a system in which the hierarchically structured materials include materials of synthetic origin and materials of natural origin.

[0084] Some embodiments relate to a system in which the plurality of pores has a size between about 100 nm and about 5 mm.

[0085] Some embodiments relate to a system in which the macroscopically porous substrate comprises a ceramic.

[0086] Some embodiments relate to a system in which the macroscopically porous substrate comprises a metal or metal alloy.

[0087] Some embodiments relate to a system in which the macroscopically porous substrate comprises a filter.

[0088] Some embodiments relate to a system in which the macroscopically porous substrate comprises a non-woven medium.

[0089] Some embodiments relate to a system in which the macroscopically porous substrate comprises a woven fabric medium.

[0090] Some embodiments relate to a system in which the macroscopically porous substrate comprises glass fibers.

[0091] Some embodiments relate to a system in which the macroscopically porous substrate comprises a ceramic.

[0092] Some embodiments relate to a system in which the ceramic comprises one or any combination of cordierite, mullite, zeolite, natural and synthetic clays.

[0093] Some embodiments relate to a system in which the macroscopically porous substrate comprises a metal.

[0094] Some embodiments relate to a system in which the metal comprises an alloy.

[0095] Some embodiments relate to a system in which the macroscopically porous substrate comprises one or any combination of stainless steel, ferritic steel, iron-chromium alloy, austenitic steel, chromium-nickel alloy, copper, nickel, brass, gold, silver, titanium, tungsten, aluminum, palladium, and platinum.

[0096] Some embodiments relate to a system in which the macroscopically porous substrate is one or any combination of cellulose, natural rubber, latex, wool, cotton, silk, linen, hemp, flax, feather fibers, and any other natural material.

[0097] Some embodiments relate to a system in which the macroscopically porous substrate comprises any one or any combination of natural or synthetic fabrics and textiles.

[0098] Some embodiments relate to a system in which the macroscopically porous substrate comprises a particulate filter.

[0099] Some embodiments relate to a system in which the plurality of contaminants includes pathogens.

[0100] Some embodiments relate to a system in which the plurality of nanoscale features comprises a nanostructured coating.

[0101] Some embodiments relate to systems in which the nanostructured coating exhibits catalytic functionality.

[0102] Some embodiments relate to systems in which the nanostructured coating is configured to treat either gaseous or particulate contaminants.

[0103] Some embodiments relate to a system in which the nanostructured coating is at least partially coated with a secondary coating.

[0104] Some embodiments relate to systems in which the secondary coating comprises an inorganic material.

[0105] Some embodiments relate to systems in which the plurality of contaminant types are one or more of pathogens, particulates, and gas molecules.

[0106] Some embodiments relate to a system in which the pathogen comprises one or more of a virus, a bacteria, and a fungus.

[0107] Some embodiments relate to a system in which multiple contaminants are included in the flow medium.

[0108] Some embodiments relate to systems in which the flow medium comprises one or more of a gas or a liquid.

[0109] Some embodiments relate to a system in which the flow medium comprises an aqueous medium.

[0110] Some embodiments relate to a system in which the flow medium comprises one or more bodily fluids.

[0111] Some embodiments relate to systems in which the nanoscale features have a size between about 1 nm and about 30 nm.

[0112] Some embodiments relate to a system further including one or more active materials disposed on at least a subset of the plurality of nanoscale features.

[0113] Some embodiments relate to compositions in which the inorganic material comprises any of a metal, a metal oxide, silica, a zeolite, and activated carbon.

[0114] Some embodiments relate to compositions in which the metal oxide comprises silver oxide, copper oxide, and manganese oxide.

[0115] Some embodiments relate to compositions in which the nanostructured coating comprises catalytic nanoparticles that impart catalytic functionality.

[0116] Some embodiments relate to compositions in which the catalytic nanoparticles include any of the metal nanoparticles.

[0117] Some embodiments relate to compositions in which the metal nanoparticles comprise any of gold, silver, platinum, palladium, ruthenium, rhodium, cobalt, iron, nickel, copper, chromium, tungsten, molybdenum, vanadium, titanium, zirconium, bimetals, and metal alloys.

[0118] Some embodiments relate to compositions in which the metal nanoparticles comprise a metal compound.

[0119] Some embodiments relate to compositions in which the metal compound comprises any of a pnictide, hydroxide, binary salt, and complex salt, or combinations thereof.

[0120] Some embodiments relate to hierarchical materials, wherein said hierarchical materials are in the form of powder particles.

[0121] Some embodiments relate to hierarchical materials in which the powder particles exhibit a size ranging from about 1 micron to about 50 microns.

[0122] Some embodiments relate to hierarchical materials, wherein said interconnected pores of said matrix exhibit a surface area to weight ratio in the range of about 10 m2 / g to about 1,000 m2 / g.

[0123] Some embodiments relate to hierarchical materials, wherein said interconnected pores of said matrix exhibit a surface area to weight ratio in the range of about 100 m2 / g to about 500 m2 / g.

[0124] Some embodiments relate to hierarchical materials in which the matrix and the nanoscale features are formed of substantially the same composition.

[0125] Some embodiments relate to hierarchical materials in which the matrix and the nanoscale features are formed of different compositions.

[0126] Some embodiments relate to hierarchical materials in which the aforementioned nanoscale features include MoS2.

[0127] Some embodiments relate to hierarchical materials, wherein said matrix comprises any of synthetic polymers, natural polymers, biopolymers, and any combination thereof.

[0128] Some embodiments relate to hierarchical materials, wherein said matrix comprises one or more biomaterials.

[0129] Some embodiments relate to hierarchical materials, wherein said biomaterial comprises any of diatomaceous earth, pollen, silica-based particulates of biological origin, and any combination thereof.

[0130] Some embodiments relate to hierarchical materials further comprising one or more active materials disposed on the interior surfaces of at least some of said pores of said matrix.

[0131] Some embodiments relate to hierarchical materials in which the active material comprises catalytic nanoparticles.

[0132] Some embodiments relate to hierarchical materials, wherein said coating exhibits a thickness ranging from about 1 micron to about 200 microns.

[0133] Some embodiments relate to hierarchical materials, wherein the macroscopically porous substrate has pore sizes ranging from about 400 nm to about 3 mm.

[0134] Some embodiments relate to hierarchical materials, wherein the macroscopically porous substrate has pore sizes ranging from about 600 nm to about 1 mm.

[0135] Some embodiments relate to hierarchical materials, wherein the macroscopically porous substrate has pore sizes ranging from about 800 nm to about 0.8 mm.

[0136] Some embodiments relate to hierarchical materials, wherein the macroscopically porous substrate has pore sizes ranging from about 1,000 nm to about 500 microns.

[0137] Some embodiments relate to hierarchical materials, wherein the macroscopically porous substrate has pore sizes ranging from about 2,000 nm to about 200 microns.

[0138] Some embodiments relate to hierarchical materials, wherein the macroscopically porous substrate has pore sizes ranging from about 2,500 nm to about 100 microns.

[0139] Some embodiments relate to hierarchical materials in which the aforementioned macroscopically porous substrate comprises one or more channels exhibiting lengths ranging from about 1 mm to about 1 m.

[0140] Some embodiments relate to hierarchical materials, wherein said channels of said macroscopically porous substrate have a substantially straight or arcuate shape.

[0141] Some embodiments relate to hierarchical materials in which at least a portion of said channels are parallel to one another.

[0142] Some embodiments relate to hierarchical materials in which at least a portion of said channels cross one another to provide a pattern of interconnected channels.

[0143] Some embodiments relate to hierarchical materials, wherein the aforementioned macroscopically porous substrate comprises any of polyurethane, polystyrene, poly(methyl methacrylate), polyacrylate, poly(alkyl acrylate), substituted polyalkyl acrylate, polystyrene, poly(divinylbenzene), polyvinylpyrrolidone, poly(vinyl alcohol), polyacrylamide, poly(ethylene oxide), polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, other halogenated polymers, hydrogels, organogel, any other polymer, and any combination thereof.

[0144] Some embodiments relate to hierarchical materials, where the aforementioned macroscopically porous substrate comprises any of random copolymers, block copolymers, branched polymers, star polymers, dendritic polymers, supramolecular polymers, and any combination thereof.

[0145] Some embodiments relate to hierarchical materials, wherein the macroscopically porous substrate has pore sizes ranging from about 2,500 nm to about 100 microns.

[0146] Some embodiments relate to a method of producing a hierarchical material for capture and inactivation of pathogens, comprising preparing a solution by dispersing a matrix precursor and a core-shell templating colloid in a solvent, and drying and calcining said solution to produce said hierarchical material.

[0147] Some embodiments relate to methods in which the aforementioned hierarchical materials are formed as hierarchically structured porous powders.

[0148] Some embodiments relate to a method further comprising applying the aforementioned hierarchically structured porous powder onto a substrate.

[0149] Some embodiments relate to methods that further comprise applying said solution to a macroscopically porous substrate prior to said drying and firing steps.

[0150] Some embodiments relate to a method of applying the aforementioned solutions to a macroporous substrate by dip coating.

[0151] Some embodiments relate to methods in which the aforementioned core-shell templated colloid comprises a polymer colloid core coated with a nano-feature forming (NFF) material.

[0152] Some embodiments relate to the method, wherein the polymer colloid core comprises polystyrene.

[0153] Some embodiments relate to methods in which the aforementioned NRF material coating exhibits a thickness in the range of about 10 nm to about 30 nm.

[0154] Some embodiments relate to methods in which the solvent comprises water.

[0155] Some embodiments relate to methods in which the aforementioned drying and calcining are carried out at a temperature ranging from about 100°C to about 500°C.

[0156] One aspect of the present teachings provides a hierarchical material for the capture and inactivation of pathogens. In some embodiments, the hierarchical material can include a matrix having a plurality of interconnected pores and a plurality of nanoscale features disposed on the surfaces of the pores. In particular, the pores of the matrix, if present, can be configured to capture at least a portion of the pathogens present in the flow medium, and the nanoscale features can be configured to inactivate the pathogens, for example, by incision of the pathogen's membrane.

[0157] In a related aspect of the present teachings, a method for producing such a hierarchical material is provided that can include preparing a solution containing a matrix precursor and a core-shell templating colloid, and heat treating the solution to produce the hierarchical material.

[0158] Another aspect of the present teachings provides a hierarchical material that includes a macroscopically porous substrate and a plurality of nanoscale features disposed on an interior surface of at least some of the pores of the macroscopically porous substrate, The pores of the macroscopically porous substrate, if present, can be configured to capture pathogens present in a flowing medium, and the nanoscale features can be configured to inactivate the pathogens, for example, by incision of a membrane of the pathogens.

[0159] A related aspect of the present teachings provides a method of making such hierarchical materials, comprising immersing a macroscopically porous substrate in a solution containing nano-roughness-forming precursors, removing the macroscopically porous substrate from the solution, and drying and calcining the macroscopically porous substrate to allow the nano-roughness-forming precursors to form a plurality of nanoscale features indicative of nano-roughness on a surface of the macroscopically porous substrate.

[0160] In one aspect, a filter is disclosed that includes a porous filtration structure and a DE coating disposed on at least a surface portion of the porous filtration structure. As described in more detail below, the porous filtration structure can filter contaminants such as viruses and other pathogens by itself (i.e., without the DE coating). In some embodiments, the combination of the porous filtration structure and the DE coating can exhibit a higher filtration efficiency relative to the filtration efficiency of the porous structure without the DE coating.

[0161] The porous structure may be in the form of a woven or non-woven filtration medium. For example, in some embodiments, the porous structure may be formed of ceramic, metal, polymeric material, fiberglass, or any combination thereof.

[0162] In some embodiments, a DE coating can improve the filtration efficiency of a bare filtration media (ie, a porous structure that does not include a DE coating).

[0163] In some embodiments, the technology described herein relates to compositions in which the secondary coating enhances CO2 sorption function and storage.

[0164] In some aspects, the technology described herein relates to systems in which the hierarchically structured materials are of synthetic and natural origin.

[0165] In some aspects, the technology described herein relates to compositions in which the secondary coating enhances catalytic, sorptive, or biocidal functions.

[0166] In some embodiments, the technology described herein relates to compositions in which the secondary coating enhances CO2 sorption function and storage.

[0167] In some aspects, the technology described herein relates to a composition further comprising one or more active materials disposed on at least a subset of the plurality of nanoscale features.

[0168] In some aspects, the technology described herein relates to compositions in which one or more active materials enhance sorption functionality.

[0169] In some aspects, the technology described herein relates to compositions in which one or more active materials enhance biocidal function.

[0170] In some aspects, the technology described herein relates to compositions in which one or more active materials enhance catalytic function.

[0171] In some aspects, the technology described herein relates to compositions, wherein the one or more compositions of the one or more active materials include one or more of catalytic nanoparticles, zeolites, MOFs, organic, inorganic, or polymers.

[0172] In some aspects, the technology described herein relates to compositions in which a plurality of nanoscale features comprises any of oxides, mixed oxides, transition metal oxides, zeolites, oxohydroxides, aluminates, silicates, aluminosilicates, titanates, oxometalates, vanadium, silica, ceria, alumina, titania, zirconia, nickel oxide, cobalt oxide, tin oxide, manganese oxide, magnesium oxide, precious metal oxides, platinum group metal oxides, molybdenum oxide, tungsten oxide, rhenium oxide, chromium oxide, rare earth oxides, and any combination thereof.

[0173] A further understanding of the various aspects of the embodiments can be obtained by reference to the following detailed description in conjunction with the associated drawings, which are briefly described below.

[0174] The drawings are not necessarily to scale or exhaustive. Instead, emphasis is placed on illustrating the principles of the embodiments described herein. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments consistent with the present disclosure. Together with the description, the drawings serve to explain the principles of the present disclosure. [Brief description of the drawings]

[0175] In the diagram:

[0176] [Figure 1] 1 shows representative scanning electron microscope (SEM) images of examples of various naturally occurring structured materials that may be used in different embodiments.

[0177] [Diagram 2] 1 illustrates a hierarchical structure of a hierarchical material according to some embodiments.

[0178] [Diagram 3] 3A-3C show various examples of the internal structure of a hierarchically structured composite material 300 according to some embodiments.

[0179] [Figure 4A]4 shows a macroscopic porous substrate 400 and a plurality of hierarchically structured particles 410 according to some embodiments.

[0180] [Figure 4B] 1 illustrates the application of nano-features on a macroscopic porous substrate according to some embodiments. [Figure 4C] 1 illustrates the application of nano-features on a macroscopic porous substrate according to some embodiments.

[0181] [Diagram 5] 5 illustrates an example of a filter 500 according to some embodiments.

[0182] [Figure 6A] 1 shows SEM images of the porous structure of a filter modified with hierarchically structured microparticles according to some embodiments. [Figure 6B] 1 shows SEM images of the porous structure of a filter modified with hierarchically structured microparticles according to some embodiments. [Figure 6C] 1 shows SEM images of the porous structure of a filter modified with hierarchically structured microparticles according to some embodiments. [Figure 6D] 1 shows SEM images of the porous structure of a filter modified with hierarchically structured microparticles according to some embodiments.

[0183] [Figure 7A] 1 shows the results of antibacterial testing using DE with manganese oxide nanostructure coating with nano-rough edges, according to some embodiments.

[0184] [Figure 7B] 1 shows optical microscope images of agar plates with extracted Staphylococcus aureus from unmodified and modified medi after 60 minutes of incubation according to some embodiments.

[0185] [Figure 8]8 shows a flow chart of a method 800 for producing a coating composed of naturally occurring hierarchically structured particulates, according to some embodiments.

[0186] [Figure 9] 1 illustrates a process for producing a modified macroscopically porous substrate according to some embodiments.

[0187] [Figure 10] 1 shows a combination of porous particulates and nanoscale features (NFs) formed at the pore-matrix interface according to some embodiments.

[0188] [Figure 11] 1 shows a macroscopic substrate coated and / or modified with a combination of NFs and a microporous coating formed at the pore-matrix interface according to some embodiments.

[0189] [Figure 12] 1 shows a macroscopic substrate with NFs formed at the interface between the pores and channels of the macroscopic substrate according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0190] A further understanding of the various aspects of the present teachings can be found in the following description taken in conjunction with the associated drawings.

[0191] Various embodiments take advantage of the above-described properties of hierarchical or surface nanostructures, for example, by utilizing biomineralized particles (e.g., DE) as a substrate or scaffold for depositing or growing spiny nanostructured features.

[0192] Compared to synthetic materials, naturally occurring materials, for example produced by living organisms, may prove superior in the above-mentioned properties and applications. Their structures are often highly organized at all scales of dimensions from molecular to nanometer, micrometer, and macroscale, and this organization is usually hierarchical. Furthermore, naturally occurring materials may also be relatively inexpensive. Examples of such naturally occurring materials include biominerals derived from single-celled microorganisms such as diatoms, coccolithophores, and radiolarians, which have rigid cell walls made of silica (diatoms and radiolarians) or calcium carbonate (coccolithophores) with genetically controlled hierarchical nanopatterns.

[0193] For example, diatomaceous earth (DE) is a naturally occurring porous biomaterial originating from unicellular algae called diatoms. DE exhibits complex 3D porous hierarchical structures at the nano- and micro-scales. This naturally occurring material is non-toxic and is widely used in commercial applications from agriculture to industrial fields. It has been applied as a wastewater purification filtration medium, adsorbent, mechanical pesticide, etc. Surface-modified DE has been applied in wastewater filtration, sorption and catalysis.

[0194] In addition to the structural properties mentioned above, a phenomenon observed in some natural organisms is the use of surface nanostructures to introduce multiple functions. For example, the nanostructures of butterfly wings provide color, mechanical properties, and water repellency. The wings of some species of cicadas, dragonflies, and damselflies have mechanocidal nanopillars that prevent pathogen attachment and / or disrupt the outer membrane or wall of pathogens, thus inactivating them, through various mechanisms.

[0195] Practical applications of some of the above properties of hierarchical or surface nanostructures have yet to be realized and utilized in industry. These applications could utilize the above properties separately, individually, or in various combinations. However, such applications have not existed until now.

[0196] In general, various embodiments may utilize different kinds of naturally occurring microparticles with intricate structures and morphologies. Some of these microparticles may be derived from the mineral skeletons of zooplankton and plants. Such biominerals, such as diatom biosilica (also known as diatomaceous earth or DE), may be utilized as templates for the synthesis of novel functional materials. Furthermore, microparticles of organic origin, such as spores and pollen, may be used as scaffolds / supports for further modification.

[0197] FIG. 1 shows representative scanning electron microscope (SEM) images of examples of various naturally occurring structuring materials that may be used in different embodiments. More specifically, FIG. 1 includes nine panels, labeled alphabetically from (A) to (I). Panel (A) shows examples of various diatoms. Panels (B)-(F) and (I) show SEM images of diatomaceous earth (DE) (panel (B)), radiolarians (panel (C)), diatom scaly xanthophyte: Malomonas costata (panel (D)), foraminifera gallinae (panel (E)), coccolithophorids (panel (F)), and fungal teliospore Ustilago utriculosa (panel (I)), respectively. Additionally, panel (G) shows an SEM image of SiO2 particulates obtained from pineapple peel, and panel (H) shows an SEM image of an assemblage of spores and pollen particles from various plants.

[0198] DE is one example of a naturally occurring porous biomaterial (BM) utilized in various embodiments. Similarly, some embodiments may utilize other examples of naturally occurring materials that exhibit porous structures or surfaces with a rough, prickly morphology. These examples include organic-based materials such as pollen, spores, inorganic-based BM such as biogenic silica in the form of particulates from pineapple peel, biogenic silica in other marine organisms such as microsilica spheres from marine sponges (e.g., Geodia macandrewii), and biogenic calcium carbonate also found in various zooplankton and marine sponges (e.g., calcareous sponges). While the remainder of this disclosure describes embodiments that use DE, it should be understood that alternative embodiments may use other types of BM as described above in place of or in addition to DE.

[0199] Surface functionalization of naturally occurring material (e.g., DE) scaffolds with nanostructured features can broaden their material applications and create multifunctional, hierarchically structured materials with enhanced biocidal, sorptive and / or catalytic properties. The introduction of nanostructured coatings with spiny surface morphology and / or high surface area simultaneously results in further increases in the surface area and new surface chemical compositions of the DE. Such materials may then be used for further modification to introduce active materials or functional active sites.

[0200] Existing applications of BMs, including DEs, do not take advantage of some capabilities of BMs at the nano level that can be enhanced and utilized after modification of the BMs. More specifically, some of the embodiments disclosed herein take advantage of the modification of BMs, such as DEs, with surface-bound nanostructured features or nanoscale features with various morphologies. In various embodiments, the nanoscale features can have dimensions ranging from 1 nm to 50 nm. The features can have a thorn-like morphology in at least some portions. In various embodiments, nanofeatures with thorn-like morphology can include shapes such as cones, sawtooth cross sections, tapered cylinders, or spikes, the base of which has a size of 1 nm to 10 nm, the height of which has a size of 1 nm to 50 nm, and the aspect ratio (defined as the ratio of the height to the base) is 50 to 0.02.

[0201] In various embodiments, the modification of the BM may introduce micro- and mesoporous coatings with various surface morphologies (nanoroughness) that may include spikes, flower-like morphologies, spinous morphologies, needles, pillars, etc. In various embodiments, the addition of protrusions may result in an increase in surface area as well as changes in surface chemistry and composition.

[0202] In some embodiments, instead of naturally occurring materials, synthetic materials of approximately the same dimensions can be used as scaffolds or matrices to introduce nanostructure features on their surfaces. Such materials may be referred to as hierarchically structured materials of synthetic origin. When describing functionality or applications, both types of materials, natural or synthetic, are simply referred to as hierarchically structured materials. More specifically, hierarchically structured materials of natural or synthetic origin may also be referred to as hierarchically structured microparticles or simply hierarchical microparticles.

[0203] In some embodiments, the specific surface morphology and composition of the surface coating introduces multiple new functions, including mechanobiotic properties for pathogen inactivation, sorption and catalytic functions. In some embodiments, the modification of DE surfaces with structural nanoscale features enables the treatment (e.g., capture, inactivation) of pathogens such as viruses and other pathogenic microorganisms, as well as the treatment of gaseous and particulate pollutants.

[0204] The combination of the hierarchical DE porous structure with nano-rough coatings and their compositions may provide a synergistic effect in the inactivation of contaminants such as bacteria, viruses and other pathogenic organisms.

[0205] In many embodiments, the hierarchically structured coatings described herein provide DEs with enhanced sorption functionality due to a significant increase in surface area. These properties can be exploited in sorption applications including carbon sequestration, carbon dioxide capture and storage, carbon dioxide capture and storage, and conversion through the incorporation of high surface area materials (e.g., MOFs) and catalysts.

[0206] Such materials can find many applications including air and water purification and decontamination, sorption, catalysis, filter renewal, and sensors.

[0207] In particular, hierarchically structured materials with modified surface morphology and composition can be applied to porous macroscopic substrates to create hierarchically porous functional materials with enhanced properties for air purification and depollution.

[0208] Air purification and decontamination systems according to some embodiments of the present teachings include hierarchical material structures featuring micron-scale pores and anti-pathogenic nanoscale surface features for multifaceted biocidal solutions. In some implementations of such systems, the porous surfaces with large surface areas can efficiently capture pathogens, while the surface nanostructures on the porous surfaces can disrupt or cut open the outer membranes or walls of a wide variety of pathogens.

[0209] FIG. 2 illustrates a hierarchical structure of a hierarchical material according to some embodiments. More specifically, FIG. 2 includes a diagram of a hierarchical material 200, a particulate 210, a first set of nanoscale features 220, a surface modification feature set 230, and a second set of nanoscale features 240. The particulate 210 may be a natural particulate, such as DE, or a synthetic particulate. FIG. 2 illustrates the generation of the hierarchical material 200 from the particulate 210 by surface modification.

[0210] Typical dimensions of the hierarchical particulates can be in the range of about 1 micron to about 50 microns, such as in the range of about 5 microns to about 45 microns, or in the range of about 10 microns to about 40 microns, or in the range of about 15 microns to about 35 microns, or in the range of about 20 microns to about 30 microns.

[0211] This figure shows different levels of the hierarchy of a hierarchical material 200. Starting with a particulate 210, a first level of nanostructure is created by adding a first set of nanoscale features 220 to some or all of the surface of the particulate 210. A second set of features is then created by adding a second set of nanoscale features 240, shown as an additional layer 235 within a surface modification feature set 230, to some or all of the surface of the first set of nanoscale features 220.

[0212] In some embodiments, the particulate 210 can be a naturally occurring material that can be modified to produce a hierarchical material 200 having a plurality of nanoscale features, such as those shown in the first set of nanoscale features 220. The shape, size, and internal structure of the particulate can depend on the type of naturally occurring material, some examples of which were described in connection with Figure 1. The plurality of nanoscale features can be present on the surface of the particulate creating a nanostructured coating.

[0213] The first set of nanoscale features may enable functionality such as a sorptive, biocidal, or catalytic function.

[0214] The first nanoscale feature set may be further modified to include additional features having additional functionality. The additional features may include features such as those shown in second nanoscale feature set 240. The additional functionality introduced by second nanoscale feature set 240 may include functionality such as sorption functionality, biocidal functionality, or catalytic functionality.

[0215] In some embodiments, modification of a microparticle surface with a set of multiple nanoscale features creates a set of nanostructured coatings.

[0216] In some embodiments, the nanostructured coating may form a continuous film / coating on the surface of the microparticle, hi other embodiments, the nanostructured coating may form a discontinuous coating, or discontinuous segments of a coating.

[0217] In some embodiments, the first set of nanoscale features 220 may enable a sensing function.

[0218] In some embodiments, the second set of nanoscale features 240 may enable a sensing function.

[0219] In some embodiments, the combination of both nanoscale feature sets 220 and 240 may enable sensing functions.

[0220] In some embodiments, the nanostructured coating can have a sensing function.

[0221] In some embodiments, the first nanoscale feature set 220 or the second nanoscale feature set 240 may be formed directly on the surface of the microparticle via wet chemical modification, in which a microparticle of natural or synthetic origin is reacted / chemically treated with a nanoscale forming (NFF) precursor.

[0222] In some embodiments, the surface of the microparticles may be treated with preformed nanoscale features.

[0223] In some embodiments, the preformed nanofeatures can be attached to the surface of the microparticles via covalent bonds, ionic bonds, van der Waals bonds, and combinations thereof.

[0224] In some embodiments, the nanostructured coating may have microporosity, mesoporosity, or a combination of both. The nanostructured coating may have a variety of surface morphologies (nanoscale features), such as spikes, flower-like morphologies, thorny morphologies, needles, pillars, etc. Regardless of the particular shape, these extrusions may result in a significant increase in surface area and changes in surface chemistry and / or composition.

[0225] In some embodiments, the hierarchically structured materials can have air purification and decontamination functions, which can include the treatment of various air pollutants, including particulate matter, gaseous pollutants, and pathogens.

[0226] In some embodiments, when the hierarchically structured material is used in sensing applications, air contaminants can be the stimuli or analytes.

[0227] By way of example, the nanoscale features may include any of the following: oxides, mixed oxides, transition metal oxides, zeolites, hydroxyapatites, oxohydroxides, aluminates, silicates, aluminosilicates, titanates, oxometalates, vanadium, silica, alumina, titania, zirconia, nickel oxide, copper oxide, ceria, cobalt oxide, tin oxide, manganese oxide, magnesium oxide, precious metal oxides, platinum group metal oxides, molybdenum oxide, tungsten oxide, rhenium oxide, chromium oxide, rare earth oxides, and any combination thereof.

[0228] In some embodiments, the nanoscale features may include transition metal chalcogenides such as molybdenum disulfide (MoS2), titanium disulfide (TiS2), tungsten disulfide (WS2), TaS2, ZrS2, WSe2, Sb2Se3, NbSe2, and Bi2Te3.

[0229] In some embodiments, the nanoscale features may include layered double hydroxides, such as natural hydrotalcite (Mg6Al2(OH)16CO3x4H2O), silicate clays, boron nitride, transition metal carbides and nitrides (also called MXenes).

[0230] In some embodiments, the nanoscale features may include a graphene-based material, such as graphene oxide.

[0231] By way of example, the nanoscale features can include a variety of manganese oxides and hydroxides of Mn oxides having different valence states of Mn, including MnO(OH), MnO, MnO2, Mn2O3, Mn3O2, and mixtures thereof.

[0232] In some embodiments, the surface nanostructures of first nanoscale feature set 220 may be further modified to form surface modified feature set 230 to enhance or add functionality, such as sorptive, biocidal or catalytic functionality.

[0233] In some embodiments, the sorption function may include sorption and storage of CO2.

[0234] In some embodiments, one or more active materials may be disposed on a surface of at least some of the nanostructures of the first nanoscale feature set 220. The active materials may exhibit photocatalytic functionality, photothermal catalytic functionality, photoelectrocatalytic functionality, etc., depending on the application requirements. The active materials may include one or more active sites thereon.

[0235] In some embodiments, the active material may include catalytic nanoparticles.

[0236] In some embodiments, the catalytic nanoparticles include nanoparticles made of metal oxide, mixed metal oxide, or metal sulfide nanoparticles, some specific examples include copper oxide, alumina, titania, zirconia, nickel oxide, cobalt oxide, tin oxide, manganese oxide, magnesium oxide, noble metal oxides, platinum group metal oxides, tungsten oxide, chromium oxide, or combinations thereof.

[0237] In some embodiments, the catalytic nanoparticles include metal nanoparticles such as gold, silver, platinum, palladium, ruthenium, rhodium, cobalt, iron, nickel, copper, chromium, tungsten, molybdenum, vanadium, titanium, zirconium, bimetallics, metal alloys, metal compounds such as peptides, hydroxides, binary salts, and complex salts, or combinations thereof.

[0238] In some embodiments, the modifications may include chemical functionality on the surface of the nanostructured features.

[0239] In some embodiments, the functionality may include, but is not limited to, organic materials, inorganic materials, or combinations thereof. Some examples of such materials include, but are not limited to, amines, thiols, aluminum hydroxide, various quaternary ammonium salts such as hexadecyltrimethylammonium bromide, other types of surfactants, or enzymes.

[0240] In some embodiments, the nanoscale features may be further coated with inorganic materials such as metals, metal oxides such as silver, copper oxide, manganese oxide, silica, zeolites, and activated carbon.

[0241] In some embodiments, the nanoscale features may be further coated with a metal-organic framework (MOF).

[0242] In some embodiments, the active material may include a polymeric material.

[0243] In some embodiments, the active material may include an organometallic complex.

[0244] In some embodiments, both the nanoscale features and the active material may have similar compositions but different morphologies. In some embodiments, both the nanoscale features and the active material may have different compositions.

[0245] In some embodiments, the active material may be attached via covalent bonds, ionic bonds, van der Waals bonds, and combinations thereof.

[0246] In some embodiments, functionalization of nanoscale features with active materials can be introduced by wet chemical modification, infiltration, physical vapor deposition, atomic deposition, evaporation, sputtering, ion impregnation, and any combination thereof.

[0247] In some embodiments, the scaffolds of hierarchical materials may be of synthetic origin and may, for example, be modified with nanostructural features in the same manner as naturally occurring material scaffolds using the techniques of the present embodiments.

[0248] 3 shows various examples of the internal structure of a hierarchically structured composite material 300, according to some embodiments. The hierarchically structured material 300 can include a matrix 320 formed by a number of intersecting elements 320a patterned to provide a number of interconnected pores 320b.

[0249] In some embodiments, the interconnected pores 320b of the hierarchical material 300 may exhibit cross-sectional dimensions in the range of about 50 nm to about 10 microns, e.g., in the range of about 100 nm to about 5 microns, or in the range of about 500 nm to about 1 micron. In some embodiments, the interconnected pores 320b of the hierarchical material 300 may exhibit a surface area to weight ratio (specific surface area, SSA) in the range of about 10 m2 / g to about 1,000 m2 / g, or in the range of about 100 m2 / g to about 500 m2 / g.

[0250] In some embodiments, the hierarchical microparticles may have a single type of porosity, including microporous, mesoporous, or macroporous, hi some embodiments, the microparticles may have multiple porosities, i.e., exhibit hierarchical porosity.

[0251] In some embodiments, both the nanoscale features and the matrix can have similar compositions but different morphologies, hi some embodiments, the nanoscale features and the matrix can have different compositions.

[0252] By way of example, the matrix may comprise any of an oxide, mixed oxide, mixed oxides of one or more of Group I, II, III, IV, V, VI elements, zeolites, oxohydroxides, aluminates, silicates, aluminosilicates, titanates, oxometalates, metal organic frameworks, vanadium, silica, alumina, titania, zirconia, hafnia, nickel oxide, cobalt oxide, tin oxide, manganese oxide, magnesium oxide, precious metal oxides, platinum group metal oxides, molybdenum oxide, tungsten oxide, rhenium oxide, tantalum oxide, niobium oxide, chromium oxide, scandium, yttrium, lanthanum, thorium, rare earth oxides, and any combination thereof.

[0253] In some embodiments, the matrix may include any of a synthetic polymer, a natural polymer, a biopolymer, and any combination thereof.

[0254] In some embodiments, the interconnected pores of the hierarchical material can include one or more channels having a variety of geometric shapes and can be arranged relative to one another in a variety of different patterns. For example, at least one of the channels may have a substantially straight or arcuate shape. Furthermore, in some embodiments, one or more of the channels may be parallel to one another or may intersect to provide a pattern of interconnected channels.

[0255] In some embodiments, the hierarchical material may be in the form of spray-dried particles.

[0256] In some embodiments, the hierarchically structured materials may have microporosity, mesoporosity, microporosity, or may have hierarchical (eg, bimodal) porosity.

[0257] Figure 4A shows a macroscopic porous substrate 400 and a plurality of hierarchically structured particles 410 according to some embodiments. Figures 4B and 4C show the application of nano-features on a macroscopic porous substrate according to some embodiments.

[0258] The macroscopic substrate 400 includes a plurality of walls 430 separated by channels 420. Additionally, the hierarchically structured particles 410 are applied as a coating to some or all of the surface of one or more of the walls 430 of the macroscopic substrate 400.

[0259] In some embodiments, the channels 420 exhibit lengths ranging from about 1 mm to about 1 m, for example, ranging from about 10 mm to about 0.1 m. The channels 420 may have a variety of geometric shapes and may be arranged relative to one another according to a variety of different patterns. For example, at least one of the channels 420 may have a substantially straight or arcuate shape. Furthermore, in some embodiments, one or more of the channels 420 may be parallel to one another or may intersect to provide a pattern of interconnected channels. In some embodiments, a combination of parallel and intersecting channels may be used.

[0260] In some embodiments, the macroscopic porous substrate may have pore sizes in the range of about 100 nm to about 5 mm, e.g., in the range of about 400 nm to about 3 mm, or in the range of about 600 nm to about 1 mm, or in the range of about 800 nm to about 0.8 mm, or in the range of about 1,000 nm to about 500 microns, or in the range of about 2,000 nm to about 200 microns, or in the range of about 2,500 nm to 100 microns. In the context of the present disclosure, average pore size refers to, for example, the pore size or cross-sectional dimension (e.g., the maximum or average cross-sectional dimension), for example, in the case of high aspect ratio pores (where the ratio of the long dimension to the short dimension of the pore is greater than 1.5).

[0261] In some embodiments, the hierarchically structured microparticles may include hierarchical materials of natural origin or hierarchical materials made from synthetic scaffolds, in some embodiments, a combination of both types of materials may be applied as a coating on the macroscopic substrate.

[0262] 4B and 4C, the nanoscale features 440 may be disposed directly on the surface of the macroscopic porous substrate. In particular, the nanoscale features 440 may be disposed directly on the surface of the walls 430 at the interface between the macroscopic porous substrate 400 and the pores or channels 420.

[0263] Referring to FIG. 4C, in some embodiments, the surface of the macroscopic porous substrate may be chemically modified by a surface treatment. For example, the surface treatment may include immersing the macroscopic porous substrate in a solution containing a nanoscale forming (NFF) precursor 450 (step 460), followed by heat treatment (step 470). As a result, the NFF 450 may form a plurality of nanoscale features on the macroscopic porous substrate that exhibit nano-roughness. In some embodiments, such an NFF precursor may be considered a nano-roughness forming (NRF) precursor.

[0264] In some embodiments, the NRF precursor may include at least one complex salt of an alkali metal, an alkaline earth metal, a group (III) metal, and a transition metal salt. In some embodiments, the NRF precursor may include a salt with thio and seleno anions and metal cations ([PPh4]+ and [NEt4]+), such as ammonium tetrathiomolybdate, ammonium tetrathiovanadate, piperidinium tetrathiotungstate, and tetraethylammonium tetraselenotungstate. In some embodiments, the NRF precursor may include potassium permanganate (KMnO4), manganese sulfate, or manganese(II) chloride (MnCl2).

[0265] In certain embodiments, the NFF precursor may be in the form of a sol-gel precursor, a nanoparticle precursor, or any combination thereof. In some such embodiments, the sol-gel matrix precursor material may include silica, alumina, titania, or ceria and / or zirconia sol-gel, and the nanoparticle precursor may include single or mixtures of nanoparticles of the above matrix materials.

[0266] In some embodiments, the NFF precursor can include a graphitic material.

[0267] In some embodiments, a binder can be added to improve adhesion and mechanical robustness of the hierarchical particulate coating to the surface of the macroscopic substrate wall 430. By way of example, the binder can include metal oxide nanoparticles, such as silica or alumina. In some embodiments, the size of the binder particles can be substantially similar to or larger than the pores on the surface of the particles 410. In some embodiments, the coating can exhibit a thickness in the range of about 1 micron to about 200 microns, or in the range of about 10 microns to about 100 microns. In some embodiments, the coating can be formed as a continuous film. In other embodiments, the coating can be formed as a plurality of discontinuous segments.

[0268] In other embodiments, the coating may comprise a discontinuous coating, i.e., a coating having multiple isolated segments, or may completely fill the pores of the macroscopic substrate, hi other embodiments, the coating may comprise a collection of discrete hierarchically structured particulates comprising islands, clusters, or aggregates of multiple materials.

[0269] In certain embodiments, the macroscopically porous substrate can be made from ceramic materials such as cordierite, mullite, zeolite, and natural or synthetic clays. In certain embodiments, the macroscopically porous substrate can be made from one or more metals and / or metal alloys such as stainless steel, ferritic steel (e.g., iron-chromium alloys), austenitic steel (e.g., chromium-nickel alloys), copper, nickel, brass, gold, silver, titanium, tungsten, aluminum, palladium, platinum, and any combination thereof.

[0270] In some embodiments, the macroscopically porous substrate may be implemented as a particulate filter.

[0271] In certain embodiments, the macroscopically porous substrate may be made from polymers such as polyurethane, polystyrene, poly(methyl methacrylate), polyacrylate, poly(alkyl acrylate), substituted polyalkyl acrylate, polystyrene, poly(divinylbenzene), polyvinylpyrrolidone, poly(vinyl alcohol), polyacrylamide, poly(ethylene oxide), polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, other halogenated polymers, hydrogels, organogel, and any combination thereof. Other polymers with different architectures such as random and block copolymers, branched, star and dendritic polymers, and supramolecular polymers can be utilized as well.

[0272] In certain embodiments, the macroscopically porous substrate may be made of glass fiber. In certain embodiments, the macroscopically porous substrate may be made of one or more natural materials, such as cellulose, natural rubber (e.g., latex), wool, cotton, silk, linen, hemp, flax, feather fiber, and any combination thereof. In certain embodiments, the macroscopically porous substrate may be made of natural or synthetic fabrics and textiles, and any combination thereof.

[0273] In some embodiments, the macroscopically porous substrate may be a filter.

[0274] In some embodiments, the porous structure of a filter according to the present teachings can include a nonwoven fibrous medium in which the fibers are laminated into a web that is then bonded to one another by chemical, mechanical, thermal or solvent treatment bonding, and / or by fiber interlocking.

[0275] In some embodiments, filter structures according to the present teachings may be made from a woven fibrous medium in which the fibers overlap one another.

[0276] In some embodiments, the filter structure may be made of, include, or be coated with any of the following: fiberglass, polymeric fibers, natural fibers such as cotton, cellulose acetate, cellulose nitrate (collodion), polyamide (nylon), polycarbonate, polypropylene, polytetrafluoroethylene, stainless steel, nickel alloys, Inconel, FeCrAlY alloys, or other synthetic materials such as combinations thereof.

[0277] In some embodiments, the filter may be made of, comprise or be coated with any of the polymers such as polyurethane and / or comprise at least one of polystyrene, poly(methyl methacrylate), polyacrylate, polyalkyl acrylate, poly(divinylbenzene), polyvinylpyrrolidone, poly(vinyl alcohol), polyacrylamide, poly(ethylene oxide), polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, other halogenated polymers, hydrogels, organogel, chitin, and chitosan.

[0278] As an example, hierarchically structured microparticles 220 of natural or synthetic origin may be applied onto a macroscopically porous substrate prior to their modification.

[0279] In certain embodiments, the nanoscale features 440 may be formed from any of oxides, mixed oxides, transition metal oxides, zeolites, oxohydroxides, aluminates, silicates, aluminosilicates, titanates, oxometalates, vanadium, silica, alumina, titania, zirconia, nickel oxide, cobalt oxide, tin oxide, manganese oxide, magnesium oxide, precious metal oxides, platinum group metal oxides, molybdenum oxide, tungsten oxide, rhenium oxide, chromium oxide, rare earth oxides, and any combination thereof.

[0280] By way of example, the nanoscale features 440 may be formed from MoS2 or manganese oxide.

[0281] By way of example, the nanoscale features can have the structures and compositions described above.

[0282] In many embodiments, the compositions and materials disclosed herein provide a multifaceted mechanism for the treatment of pathogens and other particles, such as ultrafine particulate matter (PM) or PM0.1-1. As described below, in some embodiments, this goal may be achieved by rational design of a structure comprising a porous macroscopic substrate and a hierarchically structured coating deposited on the interior surface of at least some of the pores of the macroscopic porous substrate. Both the porous substrate and the coating may include nanofeatures. In some such embodiments, the structure may include hierarchical porosity ranging from micron-sized pores in the substrate to micro-, meso- and / or macroporous structures in the coating.

[0283] The terms "contaminants" and "pollutants" are used interchangeably herein to refer to a variety of inorganic, organic, and mixed inorganic and organic material structures, including naturally occurring and man-made material structures such as various microorganisms (e.g., bacteria and / or viruses), and smoke or other types of particulates. Contaminants can include particulates of organic, inorganic, and mixed origin, aerosols, including bioaerosols, and gaseous pollutants such as VOCs. In general, contaminants can include different types of particulates or organisms that can accumulate on a filter during use and reduce the performance of the filter. Degradation can include a decrease in the rate at which a filter can purify air, or the amount or type of pollutants that the filter can capture in a unit of time.

[0284] Many embodiments of the present teachings provide material structures with unique properties applicable to, for example, antiviral and antimicrobial air purification, hi some embodiments, the material structures may be applied to antiviral and antimicrobial liquid purification.

[0285] More specifically, the material integrates hierarchical structures with various length scales, each rationally tailored for a multifaceted approach to pathogen capture and elimination that relies on micron-scale pores for capture of pathogens and other particulates, and nanoscale features (e.g., roughness, sharp edges, knife-edge features, wrinkles, etc.) of the pore-matrix interface for destruction of pathogens. For the tailoring of hierarchical structures, the size of the micron-scale pores can be engineered to enhance the capture efficiency of the target pathogens, and the size of the nanoscale features can be engineered to destroy pathogens more efficiently. Thus, features can be engineered with length scales commensurate with the dimensions of the relevant target pathogens.

[0286] In some embodiments, the hierarchical materials disclosed herein may be used in the form of a coating, such as a coating having a rough surface, deposited on a macroscopically porous substrate.

[0287] In some embodiments, the hierarchical materials disclosed herein may be used in the form of a coating on a flat surface.

[0288] A hierarchical material according to embodiments of the present teachings may be configured to treat at least a portion of one or more types of pathogenic organisms present in a flow medium, if present. In some embodiments, the hierarchical material may include a macroscopic porous substrate, a coating, and optional active sites configured to treat at least one type of pathogen present in the flow medium. In many embodiments, the flow medium may be either a gas or a liquid. By way of example, the flow medium may be air or water. In some embodiments, the flow medium may be an aqueous medium. In some embodiments, the flow medium may be a bodily fluid (e.g., blood).

[0289] Pathogenic organisms may include any of a virus, bacteria and fungi.

[0290] In some embodiments, the specific surface morphology and composition of the coating introduces multiple new functions, including mechanical bactericidal properties for pathogen inactivation, sorption and catalytic functions. In some aspects, the present disclosure relates to the modification of particulate surfaces (e.g., DE) with structural microscopic and nanoscale features designed to efficiently treat (e.g., capture, inactivate) viruses and other pathogenic microorganisms, as well as treat gaseous and particulate pollutants.

[0291] Modified particles according to the present teachings can also be effectively used to treat contaminants present in liquid media, such as water.

[0292] The use of surface nanostructures to mechanically damage the external membrane or wall of pathogens and thus inactivate them is a common motif observed throughout nature. For example, the wings of some species of cicadas, dragonflies, and damselflies possess mechanocidal nanopillars. The mechanisms of action are diverse. For example, surface roughness can modify the contact angle compared to flat surfaces, prevent pathogen attachment, or provide sharp points or edges of length scales commensurate with the dimensions of the relevant pathogens. Synthetic systems with biocidal effects have been demonstrated in a variety of morphologies, including nanopillars and nanosheets (also known as "nanoknives"). For example, the graphite family (e.g., graphite, graphene oxide (GO)) has been well studied for antibacterial applications. Researchers have reported that the sharp edges of GO damage bacterial membranes, leading to the release of cytoplasmic material and bacterial death. Other studies have demonstrated that graphitic surfaces modified with vertically aligned MnO2 and MoS2 nanostructures have high antibacterial effects. These studies have been limited to liquid-state applications. Furthermore, their material selection, process and volume requirements limit the commercial viability of the technology.

[0293] In some embodiments, modification of DE surfaces with anti-pathogenic nanoscale roughness results in hierarchical material structures featuring micron-scale pores and nanoscale surface features for versatile biocidal solutions. In some implementations of such materials, the porous surface with large surface area can efficiently capture pathogens, while the nanoknives on the porous surface can disrupt or cut open the outer membrane or wall of a wide variety of pathogens.

[0294] In some embodiments, the bactericidal properties can be tuned through a synergistic effect between the surface morphology and the chemical composition of the coating, for example, using materials (e.g., metal oxides of Mn, Ce, Ca) that can chemically damage pathogens through the generation of reactive oxygen species (ROS).

[0295] In some embodiments, the surface-modified DE may have improved sorption and filtration capabilities due to increased surface area and specially designed coating compositions. The materials most frequently used to capture gaseous pollutants are porous materials with large surface areas and pore volumes, such as activated carbon, zeolites, metal oxides and their derivatives. In various embodiments, the design of the adsorbent material on a macroporous support combines the sorption functionality with nanostructuring, preventing its compression and back pressure increase while maintaining its high surface area. Surface modification of DE could improve the overall sorption capacity through grafting and nanostructuring of common VOC adsorbent materials.

[0296] As an example, the magnitude of specific surface area (SSA) here is evaluated relatively, i.e., SSA is considered to be enhanced when the initial material has a lower surface area than the structured material of the same material after modification. For example, sand particles with a similar composition (SiO2) as DE have an SSA of 0.1 m2 / g. The SSA of DE can vary from 10 to 40 m2 / g due to porosity and structure. In the specific example provided herein, the SSA of DE was measured to be about 30 m2 / g. After modification with a specific MnO structure, the SSA increases to about 45 m2 / g. Activated carbons are known to have SSA in the range of 700 to 1000 m2 / g and MOFs in the range of 5000 to 7000 m2 / g. Subsequent modification with high surface area materials can further increase the SSA.

[0297] In some embodiments, the surface area can be significantly increased after modification with a metal-organic framework (MOF).

[0298] In some embodiments, catalytic functionality may be introduced by incorporating catalytic nanoparticles after the first or second modification.

[0299] In some embodiments, the nanostructured coating may provide catalytic functionality. Catalytic functionality can be introduced by incorporating catalytic particles into the coating or by nanostructuring the coating itself. For example, many metal oxides, due to their morphological nanocharacteristics, exhibit high catalytic activity for different oxidation and reduction reactions.

[0300] As described in more detail below, the combination of the structure of the micron-scale pores of hierarchical materials with the structure and composition of the pore surfaces can provide a synergistic effect on the inactivation of contaminants such as bacteria, viruses, and other pathogenic organisms.

[0301] In some embodiments, the surface morphology and porosity of the hierarchical materials at the nano- and micro-levels can be tailored to facilitate capture of viruses and bacteria and mechanically damage the viral envelope and / or capsid as well as the bacterial membrane to achieve the designed biocidal function. In this regard, the surface morphology can be tailored by adjusting the material composition and / or by adjusting the manufacturing process conditions such as the concentration of precursor materials and the process temperature.

[0302] In some embodiments, the nanoscale features may exhibit a geometry, aspect ratio, and / or size configured to facilitate the generation of mechanical damage to a pathogen. For example, typical dimensions of the nanoscale features may range from about 3 nm to about 30 nm, such as from about 10 nm to about 20 nm.

[0303] In some embodiments, the coating applied to the substrate can promote / enhance a specific filtration function. The specific filtration function may include one or more inactivation of pathogens, decomposition of organic and gaseous pollutants, and sorption (both adsorption and absorption). Sorption may include sorption of gases (e.g., VOCs, CO2, CO, ammonia and its derivatives), pollutants, or microorganisms (e.g., pathogens such as bacteria, viruses, etc.).

[0304] In some embodiments, such enhanced sorption and / or degradation properties may be due to the presence of active materials on the surfaces of the hierarchically structured microparticles.

[0305] In some embodiments, modification of a substrate with a hierarchically structured coating according to the present teachings can result in a functional substrate that can exhibit both sorptive and catalytic activity. For example, in some embodiments, the coating can include one or more metal oxides with engineered surface properties with increased affinity for specific pollutants (hydroxylated surfaces or surfaces with amine functional groups that improve adsorption of polar molecules such as formaldehyde or alcohols or hydrophilic particles) and elemental compositions with catalytic activity for the treatment of pollutants (e.g., nickel oxide, palladium oxide, mixed metal oxides).

[0306] In some embodiments, the combination of the macroscopic substrate, the coating comprising hierarchically structured particles of synthetic or natural origin, and optionally the active site / reactive material, if present, is configured to process at least a portion of one or more types of particulates present in the flow medium. By way of example, in some embodiments, the size range of particulates that can be processed is from about 1 nm to about 1 micron. In some embodiments, the size range of particulates to be processed can be in the range of about 5 nm to about 5 microns, or in the range of about 10 nm to about 1 micron, or in the range of about 100 nm to about 500 nm. This can be done by adjusting several parameters of the coating substrate (e.g., the porosity of the substrate, the size of the particles and their modifications). The arrestance or filtration of contaminants can be determined or adjusted by the particle size. The modified substrate according to some embodiments can be configured to filter (e.g., inactivate, remove) particulates having a size in the range of about 5 nm to about 5 microns, or in the range of about 10 nm to about 1 micron, or in the range of about 100 nm to about 500 nm.

[0307] In many embodiments, the compositions and materials disclosed herein provide a multifaceted mechanism for the treatment of pathogens and other particles, such as ultrafine particulate matter (PM) or PM0.1-1, as well as gaseous and liquid pollutants. This goal can be achieved by the fabrication of a composite DE structure consisting of a DE as a macroscopic porous substrate and a nanostructured coating with rationally designed morphology and composition deposited on the surface of at least some of the pores of the DE. The nanostructured composition and morphology can promote / enhance specific functions such as inactivation of pathogens (e.g., bacteria, viruses, etc.), decomposition of organic and gaseous pollutants, and sorption (both adsorption and absorption), including sorption of gases (e.g., VOCs, CO2, CO, ammonia and its derivatives).

[0308] In some embodiments, the present disclosure provides a filter having a porous structure (also referred to herein as a primary structure) modified / coated with hierarchically structured particles to capture at least a portion of the contaminants. The porous structure also provides a filtration function without a coating, so the porous structure is also referred to herein as a bare filter. In embodiments, the hierarchically structured particles provide a coating that allows for regeneration of the filter.

[0309] In many embodiments, the inclusion of a coating having hierarchically structured microparticles with or without active materials on one or more interior surfaces of the filter without blocking passages or pores can provide a functionalized filter that operates effectively with a relatively small increase in backpressure after coating. In other words, the functionalized filter can process at least some contaminants in the air (e.g., pathogens such as viruses, particulate matter, or gaseous contaminants) without significantly restricting the passage of air through the system. In this regard, the backpressure of the functionalized filter for a desired range of airflow rates can remain within an acceptable range, e.g., within about 50 times the backpressure of an uncoated filter under similar flow conditions (e.g., within a range of 0.1-10,000 CFM, or 0.5-1000 CFM, or 1-500 CFM).

[0310] By way of example, the incremental backpressure may be about 50 times, or about 40 times, or about 30 times, or about 20 times, or about 10 times or less.

[0311] As used herein, the phrase "regenerating a filter" refers to a process of improving the filtering function of a filter after it has deteriorated due to a period of use. The deterioration of filtering function may be due, for example, to the accumulation of contaminants in the filter. Renewing a filter may include, for example, removing some or all of the accumulated contaminants from the filter. Renewing a filter may include substantially restoring the condition of the filter to a state in which the filter is capable of performing its intended filtering function.

[0312] In some embodiments, renewal of the filtering function of a filter according to the present teachings may be achieved by providing energy to intermittently treat the filter, particularly its coating, such that the filter allows for inactivation of pathogens and at least partial decomposition and removal of arrested contaminants. By way of example, renewal of the filter may be achieved by heating the filter, exposing the filter to light, exposing the filter to a magnetic field, etc. at specific time intervals and / or based on an environmental trigger. For example, in some embodiments, a filter according to the present teachings having a coating may be heated to a temperature greater than about 90° C. for inactivation of at least a portion of the pathogens captured by the filter. In other embodiments, a filter according to the present teachings having a DE coating may be heated to a temperature in the range of 90° C. to 200° C.

[0313] As an example, the filter update may be initiated by some trigger, such as an environmental trigger. In various embodiments, the environmental trigger for initiation of the filter update can be based on the detection of some change in an environmental factor or an environmental factor reaching a threshold. For example, the environmental trigger may correspond to a sudden increase or an increase above a threshold in the concentration of contaminants in the ambient air, the internal temperature, the back pressure, and / or the internal pressure of the filter.

[0314] 5 illustrates an example of a filter 500 according to some embodiments. The filter 500 includes a porous structure 520 and hierarchically structured particulates 540 bonded to the porous structure. In this embodiment, the porous structure is formed from a plurality of intersecting fibers having empty spaces between them, at least some of which have the hierarchically structured particulates 540 disposed therein. In some embodiments, the hierarchically structured particulates 540 substantially fill the entire empty space between the intersecting fibers, while in other embodiments, only a portion of the empty space is filled with the particulates 540. The amount of empty space that may be filled with the particulates 540 is discussed further below.

[0315] As an example, the particulate may be a hierarchically structured particulate 200 .

[0316] 6A-6D show SEM images of the porous structure of a filter modified with hierarchically structured particulates according to some embodiments. More specifically, FIG. 6A is an SEM image of a glass fiber filtration medium, FIG. 6B is an SEM image of a glass fiber filtration medium treated with DE, and FIG. 6C and FIG. 6D are SEM images of a DE modified with surface nanofeatures.

[0317] With reference to Figure 6A, an SEM image shows the unmodified porous structure of a glass fiber media including glass fiber fibers 620. Meanwhile, Figure 6B shows a similar glass fiber media including glass fiber fibers 620 coated with hierarchically structured particulates, in this case DE particles 640. As shown in Figure 6B, the DE particles 640 occupy a majority of the void space between the glass fiber fibers of the primary porous structure. For example, the DE particles 640 occupy at least 15%, 25%, 50%, 75% of the void space between the glass fibers of the primary porous structure.

[0318] Meanwhile, Figures 6C and 6D show SEM images of DE particles treated with additional functional materials. More specifically, Figure 6C shows an image of a single DE particle 650 coated / modified with a nanostructured coating 660 having surface growth 660. Meanwhile, Figure 6D shows a portion of the nanostructured coating 650 at high magnification showing nanofeatures 660 in the form of randomly oriented plates / nanoarrays. In these figures, the surface nanofeatures include manganese oxide nanoarrays (e.g., vertically aligned sheets or wrinkles) grown on the surface of the DE. The functions of some of these structures are further described below.

[0319] Figure 7A shows the results of antibacterial testing with DE using manganese oxide nanostructure coating with nano-rough edges (e.g., vertically aligned sheets or wrinkles as shown in Figures 6C and 6D). The glass fiber plate medium shown in Figure 6D was tested for antibacterial properties with Staphylococcus aureus (ATCC6538), demonstrating a 76% reduction in viable bacteria compared to the unmodified sample. [Figure 7A shows the results of antibacterial testing with glass fiber media shown in Figures 6A-6D. The experiment involved the deposition of bacteria Staphylococcus aureus onto two types of glass fiber media for different periods of time, followed by extraction and incubation on agar plates. Bacteria were counted (colony forming units, CFU) after each period. Figure 7A shows two sets of data counts, one sample extracted from unmodified glass fiber (circles) and the other glass fiber coated with modified DE. The results show that the coated medium contained approximately 24 CFU after 60 minutes, while the unquoted glass fiber medium contained approximately 125 CFU. This corresponds to a reduction in viable bacteria of approximately 76% in the DE-modified samples compared to only approximately 40% in the unmodified samples.]

[0320] Figure 7B shows optical microscope images of agar plates with Staphylococcus aureus extracted from unmodified and modified media (corresponding to Figures 6A and 6B, respectively) after 60 min of incubation. Although the bacteria grew well on the unmodified medium during incubation (Figure 7B, left plate), almost no growth was observed after incubation on the modified filter (Figure 7B, right plate). This indicates that the MnO-modified DE coating exhibited antibacterial functionality.

[0321] FIG. 8 shows a flow chart of a method 800 for producing a coating composed of naturally occurring hierarchically structured particulates (eg, DE coating filters) according to some embodiments.

[0322] In some embodiments, the coating is composed of hierarchically structured particulate particles of synthetic origin according to some embodiments.

[0323] At 820, the filtration media is pretreated. Filtration media pretreatment can include one or more of processes such as, but not limited to, washing, drying, activation, modification with an active ingredient to improve adhesion of DE.

[0324] In some embodiments, activating the filtration media comprises a corona treatment.

[0325] At 840, the filtration media is coated. For example, DE can be deposited on the porous structure of the filtration media, thereby providing a "coated filter." DE deposition can include one or more of the following processes: dry deposition methods, such as dry powder deposition, wet deposition methods utilizing a DE slurry, such as dip coating, roll-to-roll coating, and spray coating. In these embodiments, the DE slurry can be formulated using DE particles / particulates, a solvent (e.g., water), and additives. In some embodiments, the DE particles can be modified as described above prior to slurry preparation. In some embodiments, the additives can serve different functions (e.g., binder, stabilizer, thickener) and can include organic, inorganic materials, and mixtures thereof.

[0326] In some embodiments, hierarchically structured particles can be coated onto non-porous surfaces (e.g., tables, door handles, parts of medical devices, etc.) using the methods described above.

[0327] In some embodiments, such coatings on surfaces may have antibacterial or antiviral (biocidal) functionality.

[0328] In some other embodiments, the DE particles can be modified after slurry preparation and coating.

[0329] At 860, the coated filter is processed, including, but not limited to, one or more of the processes of drying, baking, and the like.

[0330] In some embodiments, a method for fabricating a hierarchical material structure is provided.

[0331] Some embodiments provide methods of fabricating nanostructured features on the surface of a hierarchical particulate. The fabrication method may include preparing a solution containing a nanofeature precursor and a particulate (e.g., BM) and heat treating the solution to produce a hierarchically structured material.

[0332] In some embodiments, the initial modification of the microparticle is followed by a second modification, which can further enhance the surface area or introduce new functionality.

[0333] FIG. 9 illustrates a process for producing a modified macroscopically porous substrate, according to some embodiments.

[0334] In step 920, a solution can be prepared by dispersing a matrix precursor and a core-shell templating colloid in a solvent (e.g., water). The core-shell templating colloid can include a polymer colloid (e.g., polystyrene) core coated with a thin layer (e.g., 10-30 nm) of a nano-roughness forming (NRF) material.

[0335] The coating solution can then be dried and baked in step 940 to produce the hierarchical material or hierarchically structured porous particulates as described above.

[0336] The hierarchically structured porous particulates can then be applied to a macroscopic substrate, step 306. Optionally, one or more binders may be added to improve adhesion and mechanical robustness of the coating to the substrate surface.

[0337] In some other embodiments, the solution may be applied to a macroscopically porous substrate (step 930), for example by dip coating, followed by heat treatment of the coated macroscopic substrate (step 950), resulting in a macroscopically porous substrate 930 coated with a hierarchical material structure.

[0338] In these embodiments, heat treatment or dissolution of the template colloid (steps 940 or 950) may provide (i) removal of polymer portions to create a porous network, (ii) solidification of the matrix material to form a carrier for the thin NRF layer, and / or (iii) generation of nanoroughness from the NRF layer at the pore / matrix interface that may be used for pathogen destruction. Thus, heat treatment may be performed at a temperature above the melting point of the polymer colloid core. By way of example, the temperature of heat treatment may range from about 100°C to about 500°C. In some embodiments, heat treatment may be performed in a reduced pressure environment, a vacuum or near vacuum environment, or an inert gas (e.g., nitrogen or argon) environment.

[0339] In certain embodiments, the matrix material may be made of a single compound or a mixture of different compounds. The matrix material may be, for example, catalytically active, stimuli-responsive, chemically robust, degradable, and / or exhibit specific thermal and mechanical properties.

[0340] By way of example, the matrix material may include any of the following: oxides, mixed oxides, mixed oxides of one or more of Group I, II, III, IV, V, VI elements, zeolites, oxohydroxides, aluminates, silicates, aluminosilicates, titanates, oxometalates, metal organic frameworks, vanadium, silica, alumina, titania, zirconia, hafnia, nickel oxide, cobalt oxide, copper oxide, tin oxide, manganese oxide, magnesium oxide, precious metal oxides, platinum group metal oxides, molybdenum oxide, tungsten oxide, rhenium oxide, tantalum oxide, niobium oxide, chromium oxide, scandium, yttrium, lanthanum, thorium, rare earth oxides, and any combination thereof.

[0341] In some embodiments, the matrix material may include any of a synthetic polymer, a natural polymer, a biopolymer, and any combination thereof.

[0342] In some embodiments, the matrix material may include biomaterials such as diatomaceous earth, pollen, and silica-based particulates of biological origin.

[0343] In certain embodiments, the matrix material may include a semiconductor such as silicon, germanium, tin, silicon doped with a Group III or Group V element, germanium doped with a Group III or Group V element, tin doped with a Group III or Group V element, and any combination thereof.

[0344] In certain embodiments, the matrix material may include one or more metal sulfides, metal chalcogenides, metal nitrides, metal pnictides, and any combination thereof.

[0345] In certain embodiments, the matrix material may include one or more organometallic compounds, such as metal-organic frameworks, inorganic polymers (eg, silicones), organometallic complexes, or any combination thereof.

[0346] In some embodiments, the macroscopically porous substrate may be directly machined, for example by etching, to introduce surface nano-roughness. For example, etching processes may include, but are not limited to, wet etching, dry etching, ion etching, plasma etching, and the like.

[0347] In some such embodiments, nanoscale features may be formed on the microscopic particulates after the microscopic particulates are coated onto the macroscopic substrate.

[0348] In certain embodiments, the matrix precursor material may be in the form of a sol-gel precursor, a nanoparticle precursor, or any combination thereof. In some such embodiments, the sol-gel matrix precursor material may include silica, alumina, titania, ceria, and / or zirconia sol-gels, and the nanoparticle precursor may include single or mixtures of nanoparticles of the above matrix materials. In some such embodiments, the nanoparticle precursor may include an aluminum oxide hydroxide, such as boehmite.

[0349] As described herein, the "matrix precursor material" can be converted into a "matrix material" by one or more manufacturing processes, such as high temperature calcination, drying, light-induced polymerization, thermal or radical polymerization, supramolecular polymerization, other curing processes, and any combination thereof.

[0350] The above-mentioned core-shell systems can provide a combinatorial approach to materials design to systematically address specific cases: in a single manufacturing process, various pore sizes can be introduced by choosing appropriate polymer colloid diameters and different shell compositions to achieve variations in nanoscale feature dimensions tailored to achieve the desired biocidal function.

[0351] Below, several examples of hierarchical material structures and methods for their fabrication in accordance with the present teachings are described.

[0352] Example 1: Porous Microparticles + Nanoscale Features (NF) at the Pore-Matrix Interface Referring to FIG. 10, the combination of porous particulates and nanoscale features (NFs) formed at the pore-matrix interface can include, but are not limited to, the following six configurations, each of which is fabricated as described below: (i) Example 1a. Combining a nanoscale feature (NFF)-modified template material (NFF-TM) with a matrix precursor (MP) to obtain a NFF composite microparticle (NFF-CMP) (step 1010); and (ii) template removal and formation of NFs at the pore-matrix interface to obtain NF porous microparticles (NF-PMPs) (step 1012). Example 1b (i) Combining NF-modified template material (NF-TM) with MP to obtain NF composite microparticle (NF-CMP) (step 1020); and (ii) Removal of the template to obtain NF-PMPs (step 1022). Example 1c (i) Combining a template material (TM) with a MP to obtain a composite particulate (CMP) (step 1030); (ii) removing the template to obtain porous microparticles (PMPs) (step 1032); and (iii) Post-modification with preformed NFs (e.g., via impregnation, deposition, etc.) to obtain NF-PMPs. Example 1d (i) Combining the TM and MP to obtain a CMP (step 1030); (ii) removal of the template to obtain PMPs (step 1032); (iii) post-modification by NFF (e.g., by impregnation) (step 1034); and (iv) Processing to obtain NF-PMP (step 1036). Example 1e (i) Combining the TM and MP to obtain a CMP (step 1030); (ii) removing the template to obtain PMPs (step 1032); and (iii) Post-modification to introduce NFs (step 1036) (e.g., via mechanical processing, etching, etc.) (step 1038) to obtain NF-PMPs.

[0353] Example 2: Macroscopic substrates coated and / or modified with microporous coatings + nanoscale features (NF) at the pore-matrix interface Referring to FIG. 11, macroscopic substrates coated and / or modified with a combination of microporous coatings and NFs formed at the pore-matrix interface can include, but are not limited to, the following four configurations, each of which is fabricated as described below: Example 2a (i) Modification of a macroscopic substrate with preformed NF-PMPs (step 1110) (e.g., by dip coating, spray coating, roll-to-roll, etc.). Example 2b (i) modification of macroscopic substrates by attachment of NFF or NF-modified TMs and MPs (e.g., directly onto the walls of the macroscopic substrate); and (ii) Removal of the template and formation of NFs on the pore-matrix interface of the coating (step 1120). Example 2c (i) modification of macroscopic substrates with preformed PMPs; and (ii) Post-modification with NF (step 1130) or post-modification with NFF (step 1140), followed by processing to form NF. Example 2d (i) Modification of macroscopic substrates by attachment of TMs and MPs onto the channels of the macroscopic substrate; (ii) removing the template (step 1150); and (iii) post-modification with NFF or direct modification with NF (step 1152).

[0354] Example 3: Nanoscale Features (NF) at Macroscopic Substrate + Pore - Macroscopic Substrate Channel Interface With reference to FIG. 12, the macroscopic substrate having NFs formed at the interface between the pores and channels of the macroscopic substrate can include, but is not limited to, the following three configurations, each of which is fabricated as described below: Example 3a (i) modification of a macroscopic substrate by NFF (step 1210) (e.g., by dip coating, spray coating, roll-to-roll, etc.); and (ii) Processing to form a NF (step 1212). Example 3b (i) Modification of a macroscopic substrate with preformed NFs (step 1220). Example 3c (i) Processing of the macroscopic substrate (step 1230) (e.g., by etching) to form NFs.

[0355] The coating method is selected according to the type of substrate. For example, for 3D substrates, the method can be based on dip coating, while for 2D substrates (e.g., flat substrates, surfaces), the method can include roll-to-roll coating and spray coating.

[0356] The term "particulate" as used herein refers to a variety of inorganic, organic, and mixed inorganic and organic material structures, including naturally occurring and man-made material structures such as various microorganisms (e.g., bacteria and / or viruses) and smoke particulates. By way of example, such particulates may have a size of up to about 10 microns or less (e.g., "PM10"), or up to about 2.5 microns or less (e.g., "PM2.5"), or up to about 1 micron or less (e.g., "PM1"), or up to about 300 nm or less. The term "ultrafine particles" typically refers to particulates having a size of up to about 0.1 microns "PM0.1" or less.

[0357] The terms "treat" and "treatment" are used herein to refer to the oxidation, reduction, inactivation, decomposition, and / or filtration (e.g., removal) (or a combination thereof) of contaminants (e.g., gases, vapors, particulate matter, aerosols, bioaerosols, or pathogens) from a medium (e.g., a gas or liquid medium), including a flowing medium, e.g., in the form of a contaminated stream.

[0358] As used herein, the term "trapping" refers to the permanent or temporary trapping of contaminants (eg, particulates) by a structure according to the present teachings.

[0359] The terms "pore," "passage," "connecting passage," and "channel" are used interchangeably herein to refer to a material structure having at least one opening for receiving flow. Pores may be spherical or non-spherical in shape, e.g., straight, curvilinear, serpentine, bifurcated, or branched cavities that can provide enclosures or surfaces exposed to flow.

[0360] The term "size" as used herein refers to a cross-sectional dimension, e.g., a dimension such as the largest dimension, perpendicular to the elongated dimension (e.g., length) of a pore or channel (e.g., the diameter of the pore or channel) in the case of a high aspect ratio pore (where the ratio of the long dimension to the short dimension of the pore is greater than 1.5). Thus, in the embodiments described below, a pore or channel may be characterized by one or more of its cross-sectional dimension and its length.

[0361] The terms "nanostructure" or "nanoscale" refer to material structures having sizes in each of the x, y, and z dimensions that are less than 1 micron, e.g., in the range of about 100 nm to about 500 nm, or in the range of about 10 nm to about 150 nm, or in the range of about 3 nm to about 50 nm.

[0362] The terms "microstructure" or "micron-scale" refer to material structures having sizes greater than or equal to 1 micron and less than 1 mm in each of the x, y, and z dimensions.

[0363] As used herein, the term "filter" refers to a device that removes contaminants from the air by retaining and / or removing the contaminants. Filters include, but are not limited to, high efficiency particulate adsorption ("HEPA") filters, mechanical filters, sorption element filters, ionization and electrostatic filters, and photocatalytic filters.

[0364] The terms "surface nanostructures", "nanostructured features", "nanoscale features", "nanofeatures", and "nanoroughness" are used interchangeably herein and refer to nanoscale material structures having in part spike-shaped surface morphologies, flower-like morphologies, spine-like morphologies, needles, pillars, cones, sawtooth cross-sections, tapered cylinders, and other surface extrusions having dimensions in the range of 1 nm to 50 nm and an aspect ratio (defined as the ratio of height to base) of 50 to 0.02.

[0365] As used herein, in some embodiments, the term "about" refers to ±10% of the numerical value of the number with which it is used. Thus, in some embodiments, about 100 μm refers to a range of 90 μm to 110 μm.

[0366] The terms microporous, mesoporous and macroporous are defined according to the definition of the International Union of Pure and Applied Chemistry, where pores are classified as micropores (<2 nm), mesopores (2-50 nm) and macropores (>50 nm). It has been discovered that it is often beneficial for porous materials to have hierarchical pores across multiple length scales. Hierarchical porous materials must have at least bimodal porosity.

[0367] The terms "treat" and "treatment" are used herein to refer to the oxidation, reduction, inactivation, decomposition, filtration, degradation, and removal (e.g., sorption) (or combinations thereof) of contaminants (e.g., gases, vapors, particulate matter, aerosols, bioaerosols, or pathogens) from a medium (e.g., gas or liquid medium), including a flowing medium in the form of, for example, a contaminated stream. Filters used to treat the medium may have antiviral and / or antimicrobial properties.

[0368] Although some aspects have been described in the context of a system or apparatus, it is clear that these aspects can also represent a description of a corresponding method, with a block or device corresponding to a method step or feature of a method step. Similarly, aspects described in the context of a method step also represent a description of a corresponding block or item or feature of a corresponding apparatus. Some or all of the method steps can be performed by (or using) a hardware apparatus, such as, for example, a processor, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of some of the most important method steps can be performed by such an apparatus.

[0369] Those skilled in the art will appreciate that various modifications can be made to the above embodiments without departing from the scope of the present disclosure.

[0370] The foregoing description of the embodiments has been presented for illustrative purposes only. It is not exhaustive and is not intended to limit the embodiments to the precise form disclosed. Although several exemplary embodiments and features have been described, modifications, adaptations, and other implementations may be possible without departing from the spirit and scope of the embodiments. Thus, unless otherwise stated, the description is directed to one or more embodiments and should not be construed as limiting the embodiments as a whole. This is true whether the disclosure states that a feature is related to "a", "the", "one", "one or more", "some", or "various" embodiments. As used herein, the singular forms "a", "an", and "the" may include the plural unless the context clearly dictates otherwise. Furthermore, the term "combined" does not exclude the presence of intermediate elements between the combined items. Also, stating that a feature may be present indicates that the feature may be present in one or more embodiments.

[0371] In this disclosure, the terms "include," "comprise," "contain," and "have," when used following a set or system, imply open inclusion and do not exclude the addition to the set or system of other unlisted members. Further, unless otherwise stated or otherwise inferred from the context, the conjunction "or," when used, is non-exclusive and includes the meaning alternatively and / or.

[0372] Moreover, as these terms are used, a set can include one or more members, and a subset of a set can include one or more, including all, of the members of the set.

[0373] The disclosed compositions of matter, systems, methods, and devices are not limited to any particular aspect or feature or combination thereof, and the disclosed systems, methods, and devices are not required for any particular advantage or advantages to be present or problems to be solved. Although theories of operation are provided for ease of explanation, the disclosed systems, methods, and devices are not limited to such theories of operation.

[0374] Modifications and variations are possible in light of the above teachings or may be acquired from practice of the embodiments. For example, the steps described need not be performed in the same order or with the same degree of separation as described. Similarly, various steps can be omitted, repeated, combined, or performed in parallel, as necessary to accomplish the same or similar purpose. Similarly, the described systems need not necessarily include all components described in the embodiments, but may include other components not described in the embodiments. Thus, the embodiments are not limited to the details set forth above, but are instead defined by the appended claims in light of their full scope of equivalents. Moreover, the present disclosure is directed to all novel and non-obvious features and aspects of the various disclosed embodiments, both alone and in various combinations and subcombinations with one another.

[0375] While the present disclosure has been particularly described in connection with specific embodiments, many alternatives, modifications, and variations will be apparent in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications, and variations as fall within the true spirit and scope of the present disclosure.

Claims

1. A hierarchically structured material composition comprising: a porous matrix; a plurality of nanoscale features disposed on at least a portion of a surface of the porous matrix; the plurality of nanoscale features include spikes having heights ranging from 1 nm to 50 nm; A composition wherein the hierarchically structured material exhibits a surface area to weight ratio in the range of 10 m 2 / g to 1000 m 2 / g and is configured to treat multiple contaminants.

2. the hierarchically structured materials include materials of natural origin and materials of synthetic origin; Optionally, the naturally occurring material comprises diatomaceous earth; Optionally, the synthetically derived material comprises any of an oxide, a mixed oxide, a mixed oxide of one or more Group I, II, III, IV, V, VI elements, a zeolite, an oxohydroxide, an aluminate, a silicate, an alumosilicate, a titanate, an oxometallate, a metal organic framework, vanadium, silica, alumina, titania, zirconia, hafnia, nickel oxide, cobalt oxide, ceria, tin oxide, manganese oxide, magnesium oxide, a noble metal oxide, a platinum group metal oxide, molybdenum oxide, tungsten oxide, rhenium oxide, tantalum oxide, niobium oxide, chromium oxide, scandium, yttrium, lanthanum, thorium, a rare earth oxide, and any combination thereof; The composition of claim 1.

3. the plurality of contaminants includes pathogens; the plurality of nanoscale features are configured to treat the pathogen; The composition of claim 1.

4. the plurality of nanoscale features comprises a nanostructured coating; Optionally, the nanostructured coating exhibits catalytic functionality; Optionally, the nanostructured coating exhibits sorption functionality; Optionally, the nanostructured coating exhibits CO2 sorption and storage; Optionally, the nanostructured coating is configured to treat any of gaseous and particulate contaminants. The composition of claim 1.

5. the nanostructured coating is at least partially coated with a secondary coating; Optionally, the secondary coating comprises an inorganic material; Optionally, the secondary coating enhances catalytic, sorptive, or biocidal function; The composition of claim 4.

6. the hierarchically structured material comprises a plurality of microparticles; Optionally, the plurality of microparticles have a size of about 1 micron to about 50 microns. The composition of claim 1.

7. the plurality of contaminant types are one or more of pathogens, particulates, and gas molecules; Optionally, the pathogen comprises one or more of a virus, a bacterium, and a fungus; Optionally, the plurality of contaminants are contained in a flow medium; Optionally, the flow medium comprises one or more of a gas or a liquid; Optionally, the flow medium comprises an aqueous medium; Optionally, the flow medium comprises one or more bodily fluids. The composition of claim 1.

8. the nanoscale features have a size of about 1 nm to about 30 nm; The composition of claim 1.

9. the hierarchically structured material defines a plurality of interconnected pores, the interconnected pores having cross-sectional dimensions of from about 50 nm to about 10 microns; The composition of claim 1.

10. the composition of the plurality of nanoscale features comprises any of oxides, mixed oxides, transition metal oxides, zeolites, oxohydroxides, aluminates, silicates, alumosilicates, titanates, oxometalates, vanadium, silica, alumina, titania, zirconia, nickel oxide, ceria, cobalt oxide, tin oxide, manganese oxide, magnesium oxide, noble metal oxides, platinum group metal oxides, molybdenum oxide, tungsten oxide, rhenium oxide, chromium oxide, rare earth oxides, and any combination thereof; The composition of claim 1.

11. further comprising one or more active materials disposed on at least a subset of the plurality of nanoscale features; Optionally, the one or more active materials enhance at least one of a sorption function, a biocidal function, a catalytic function; Optionally, the one or more active materials comprise one or more of catalytic nanoparticles, zeolites, MOFs, organic, inorganic, or polymers; The composition of claim 1.

12. The method of claim 1, wherein the composition is deposited on the interior surfaces of at least some of the pores of a macroporous substrate. The composition of claim 1.

13. The macroscopically porous substrate comprising a filter; Optionally, said filter comprises any one or any combination of woven or non-woven media; Optionally, the medium comprises any one or any combination of glass fibers, natural or synthetic polymers, natural or synthetic fabrics and textiles; The composition of claim 12.

14. the macroscopically porous substrate comprises a metal or a ceramic; Optionally, the metal comprises an alloy; Optionally, the macroscopically porous substrate comprises one or any combination of cordierite, mullite, zeolite, natural and synthetic clays; The composition of claim 12.

15. The composition forming a coating on the interior surface, 13. The composition of claim 12, wherein optionally the coating has a thickness of from 10 microns to 100 microns.

16. The composition of any one of claims 12 to 15, wherein the plurality of pores have a size of from about 100 nm to about 5 mm.

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