Reticulated carbon composites

Abstract

To disclose a reticulated film composite and a method of fabricating a reticulated film composite suitable as a three-dimensional porous and conductive matrix which has up to 80% porosity and exhibits high recovery after compression.SOLUTION: The reticulated film composite is produced by casting and drying of a slurry which exhibits a high yield stress (i.e. greater than 50 dyne / cm2) and composed of a high MW resin dissolved in a solvent (i.e. having a solution viscosity of higher than 100 cp at 5% in NMP at room temperature) and dispersed nanoparticles of carbon of high specific surface areas (i.e. greater than 1 m2 / g, preferably greater than 10 m2 / g), examples include but not limited to conductive carbon, carbon nanotubes, graphene, activated carbon or mixture thereof.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention discloses a method for manufacturing a reticulated (porous, continuous cellular matrix structure) film composite material. Said composite material is suitable as a conductive composite material, as a gas diffusion layer of a fuel cell, or as a high-efficiency electrode of an electric double layer capacitor.

Background Art

[0002] A reticulated film composite material is a very porous, low-density solid film. A reticulated form refers to a very continuous structure like a net. Similarly, the reticulated film composite material is also made of a very continuous cellular structure and exhibits novel physical properties compared to their bulk counterparts, such as a large specific surface area and high energy absorption upon impact. Due to its excellent strength-to-weight ratio, it is optimal for catalyst media, catalyst carriers, energy storage, damping, construction of components, and protective coatings. However, when a sufficient amount of carbon (>20%) is incorporated into the solid film, in order to impart conductivity, the film often exhibits insufficient mechanical and thermal stability. The elongation at break is much lower, which means it is brittle and easily broken and cannot be deformed into a foam or reticulated film.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Thin porous films are often made of melt-processable plastics, which form the film by solution casting or extrusion and then stretch it to create a porosity of 30 - 60% within the film. Today's common thin porous films (less than 100 μm thick) are generally based on polypropylene (melting point about 160 - 165 °C), polyethylene (melting point about 110 - 135 °C), or blends thereof. For example, U.S. Patent Nos. 4,620,956 and 5,691,047 disclose melt extrusion and stretching processes for manufacturing polyolefin porous films or separators, and U.S. Patent Nos. 8,064,194 and 8,012,799 disclose solution casting processes for manufacturing polyolefin porous films or separators. Porous separators made of polyvinylidene fluoride (PVDF) (melting temperature about 165 - 170 °C) disclosed in U.S. Patent Application Nos. 2009 / 0208832 and 2010 / 0183907 are also known. A major drawback of such thin porous films is their low dimensional stability at high temperatures or lack of thermal robustness that can lead to shrinkage. Furthermore, to the author's knowledge, there are no thin porous conductive films (less than 100 μm thick) with a porosity exceeding 20% and a volume resistivity less than 10,000 Ω·cm.

[0004] PVDF has been found to be useful as a binder or coating for separators in non-aqueous electrolyte devices due to its excellent electrochemical resistance and good adhesion between fluoropolymers. The separator forms a barrier between the anode and cathode of the battery and prevents electronic short circuits while enabling high ion transport. Polyvinylidene fluoride (PVDF), and its copolymers, are used in many applications such as durable coatings, wire jackets, binders for lithium-ion batteries, chemical piping, open-cell and closed-cell foams. However, due to its high insulating property, more than 30% carbon is required to make it conductive. With such a high carbon loading, it is almost impossible to create low-density foams or films from PVDF-carbon composites.

Brief Description of the Drawings

[0005]

Figure 1

DETAILED DESCRIPTION OF THE INVENTION

[0006] “Copolymer” is used to mean a polymer having two or more different monomer units. “Polymer” is used to include homopolymers and copolymers. Resin and polymer are used interchangeably. A polymer can be homogeneous, heterogeneous, and can have a gradient distribution of comonomer units. All references cited are incorporated herein by reference. As used herein, unless otherwise specified, percent means weight percent. Crystallinity and melting temperature are measured by DSC at a heating rate of 10 °C / min as described in ASTM D3418. Melt viscosity is measured at 232 °C according to ASTM D3835 and is expressed in kPoise at 100 sec -1 and is expressed in kPoise. The dilute solution viscosity and reduced viscosity of the polymer are measured at room temperature as described in ASTM D2857.

[0007] A reticulated film or coating means a film or coating having a porous continuous cellular matrix structure. “Continuous cells” means that the pores are not surrounded. Fluids can move between the pores. The void fraction or porosity can be measured by compressing the continuous cellular matrix, measuring the density, or filling the voids with a liquid and measuring the change in density. Preferably, the voids are measured by density.

[0008] A nano-sized filler or nano-sized particle means that the size of the filler or particle is less than 1 μm, preferably less than 500 nm, more preferably less than 200 nm. The nano-sized particle can be less than 100 nm. The particle size is the volume-average particle size measured by light scattering (such as equipment from Nicom or Microtech).

[0009] High specific surface area particles refer to particles with a surface area greater than 1 m 2 / g, preferably greater than 5 m 2 / g, more preferably greater than 10 m 2 / g. Preferably, it is in the range of 1 m 2 / g to 10000 m 2 / g, preferably in the range of 1 m 2 / g to 5000 m 2 / g, 1 m 2 / g to 1000 m 2 / g, more preferably in the range of 1 m 2 / g to 700 m 2 / g, even more preferably in the range of 10 m 2 / g to 500 m 2 / g. The surface area of the particle can be 5 m 2 / g to 700 m 2 / g. Some high specific surface area particles have a three-dimensional branched structure. This is sometimes called a fractal shape that can result in particles with a large aspect ratio. The fractal shape is an aggregate with three-dimensional branches. For example, the primary particles of a conductive carbon structure can aggregate into a three-dimensional branched structure. This is composed of many closely bonded primary particles.

[0010] High molecular weight means that, using ASTM D2857, the solution viscosity measured at 5% in NMP at room temperature (25 °C) is at least 100 cp, preferably 100 cp to 10,000 cp, more preferably 100 cp to 5000 cp, or the viscosity is decreasing, and Rv is at least 0.2 dl / g and at most 2 dl / g.

[0011] The yield stress is the minimum shear stress required to initiate fluid flow. A high yield stress is at least 50 dynes / cm 2 , preferably greater than 100 dynes / cm 2 and greater than 125 dynes / cm 2 . The yield stress can be up to 5000 dynes / cm 2 , preferably up to 3000 dynes / cm 2 . Also, the slurry must be castable, which means that the solution viscosity of the slurry is less than 20,000 cP at room temperature, preferably less than 10,000 cP.

[0012] The recovery of volume or porosity after being compressed and then heated is calculated by dividing the thickness of the coating or film after being heated at 150 °C for 10 minutes after being compressed by the thickness before compression.

[0013] The present invention provides a network film composite material having nano-sized pores and a method for producing a network film composite material having nano-sized pores. The nano-sized pores have an average pore size of less than 500 nm, preferably 2 nm to 500 nm. The present invention also provides a coating made from a network film composite material having nano-sized pores, in which the porosity recovers to at least 30% of the porosity before compression after compression. The recovery of volume or porosity after being compressed and then heated can be at least 30%, preferably 50%, preferably 55%, preferably 60%, preferably 70% or the original thickness.

[0014] The network film composite material can be manufactured using different types of resins and a variety of carbon-based nano-sized particles.

[0015] The network film composite material is produced by combining high specific surface area particles and a polymer resin in a solvent at room temperature (25 °C), and has a high yield stress (50 dynes / cm 2results in a slurry that exhibits (exceeds). By casting the slurry and drying it at a high temperature, a network film composite material with nano-sized pores is formed. When the film is heated (30 - 180 °C, preferably 80 °C or higher, more preferably 110 °C or higher), the porosity of the compressed film recovers to at least 30% (preferably at least 60%, preferably 50%, preferably 55%, even more preferably at least 70%) of the original porosity before compression.

[0016] Surprisingly, slurries (made in NMP) of high specific surface area particles (i.e., nano-sized carbon-based materials such as conductive carbon, carbon nanotubes, graphene, etc.) and polymer resins (e.g., high MW-PVDF with a solution viscosity of more than 100 cp at room temperature in NMP), or high MW-PMMA (viscosity decreases and Rv exceeds 0.5 dl / g) can exhibit a high yield stress (50 dyn / cm 2 exceeding) even at low solids (i.e., total solids less than 30 wt%, preferably less than 20 wt%, more preferably less than 12%, even less than 10%). Due to the low dispersion viscosity (i.e., less than 10,000 cp at room temperature), casting is easy. When this high yield stress slurry is cast and dried at a high temperature (i.e., 50 - 180 °C, preferably 80 - 180 °C, preferably 120 °C or higher), a network film composite material with nano-sized pores is formed. The film showed recovery of porosity after compression when heated. Interestingly, these network film composite materials can be compressed to half their thickness using a calendar roll at room temperature. This simply indicates that the composite material contains at least about 50% porosity. Even more unexpectedly, the compressed composite material can expand back to more than 50% of its original height when simple polymer relaxation occurs, such as being placed in an oven at 120 °C or exposed to a potential solvent. This rebound indicates that these composite materials have a mechanically very durable continuous bubble structure. The ratio of carbon to polymer can vary greatly, and the higher the carbon content, the higher the porosity (lower density) of the composite material obtained.

[0017] The type of carbon filler can be, for example, conductive carbon, carbon nanotubes, graphene, or a combination thereof, thereby imparting high electron conductivity.

[0018] In one embodiment of the present invention, a semi-crystalline high molecular weight PVDF (having a solution viscosity exceeding 100 cp measured at 5% in NMP at room temperature) functions in the present invention.

[0019] Using high molecular weight resins such as PMMA (reduced viscosity, Rv, exceeding 0.5 dl / g) and high MW PAA (having a solution viscosity of 100 to a maximum of 1000 cp, preferably a maximum of 5000, measured in water at pH 7 at room temperature), a high yield stress slurry (exceeding 50 dyn / cm 2 can be obtained, and finally, a reticulated film composite material with properties similar to a reticulated film made of PVDF can be manufactured.

[0020] The types of fillers useful in the present invention are carbon-based materials including, but not limited to, for example, conductive carbon, carbon nanotubes, activated carbon, graphene, or combinations thereof.

[0021] Small amounts of other fillers (0 to 15 wt%, preferably less than 10 wt%) may be present in the composition. Other fillers include, for example, alumina, silica, BaTiO3, CaO, ZnO, boehmite, TiO2, SiC, ZrO2, boron silicate, BaSO4, nanoclay, Pb(Zr,Ti)O3, Pb 1-x La x Zr y O3 (0 < x < 1, 0 < y < 1), PBMg3Nb 2 / 3)3. PbTiO3, hafnia (HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, Y2O3, Al2O3, SiO2, ceramic, or a mixture thereof is included. Also, other useful organic fillers include, but are not limited to, aramid fillers and fibers, polyetheretherketone fibers, polyetherketoneketone fibers, PTFE fibers, and nanofibers, carbon nanotubes, and mixtures thereof, which are chopped fibers.

[0022] The resin should have a high solution viscosity (i.e., higher than 100 cp measured at 5% in NMP at room temperature). Preferably, the solution viscosity is 100 - 10,000 cp, more preferably 100 - 5000 cp, at 5% solids measured in NMP at room temperature. In the case of water-soluble polymers, when measured at pH 7 at room temperature (25 °C) in 2% water, the solution viscosity is 100 cp - 10,000 cp, preferably 100 cp - 5000 cp. In this application, the pH varies in the range of 2 - 12 depending on the type and use of the polymer.

[0023] Polymers (resins) useful in the present invention include, but are not limited to, the following homopolymers and copolymers: polyvinylidene fluoride (PVDF), polytetrafluoroethylene ethylene (PETFE), polyvinyl fluoride (PVF), poly(alkyl) acrylate, poly(alkyl) methacrylate, polystyrene, polyvinyl alcohol (PVOH), polyester, polyamide, polyacrylonitrile, polyacrylamide, carboxymethyl cellulose CMC, polyacrylic acid (PAA), polymethacrylic acid (PMAA). Other useful polymers include polyetherketoneketone, polyetheretherketone, and polyester.

[0024] Polyvinylidene fluoride In a preferred embodiment, the polymer is a polyvinylidene fluoride homopolymer or copolymer. As used herein, the term "vinylidene fluoride polymer" (PVDF) includes within its meaning all normally high molecular weight homopolymers, copolymers, and terpolymers. Copolymers of PVDF are particularly preferred because they are softer (having a lower Tm, melting point and reduced crystalline structure). Such copolymers include vinylidene fluoride copolymerized with at least one comonomer. The most preferred copolymers and terpolymers of the present invention are those in which the vinylidene fluoride units constitute at least 50 mol%, at least 70 mol%, preferably at least 75 mol%, more preferably at least 80 mol%, even more preferably at least 85 mol% of the total weight of all monomer units in the polymer.

[0025] Copolymers, terpolymers, and higher polymers of vinylidene fluoride can be prepared by reacting vinylidene fluoride with one or more monomers from the following group: vinyl fluoride; trifluoroethylene; tetrafluoroethylene; one or more partially or fully fluorinated α-olefins such as 3,3,3-trifluoro-1-propene, 1,2,3,3,3-pentafluoropropene, 3,3,3,4,4-pentafluoro-1-butene, and hexafluoropropene; partially fluorinated olefin hexafluoroisobutylene; perfluorovinyl ethers such as perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoro-n-propyl vinyl ether, and perfluoro-2-propoxypropyl vinyl ether; fluorinated dioxoles such as perfluoro(1,3-dioxole) and perfluoro(2,2-dimethyl-1,3-dioxole); allyl, partially fluorinated allyl, or fluorinated allyl monomers (such as 2-hydroxyethyl allyl ether or 3-allyloxypropanediol); and ethene or propene. In some preferred embodiments, the comonomer is selected from the group consisting of tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropene, vinyl fluoride, pentafluoropropene, tetrafluoropropene, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether.

[0026] Particularly preferred are copolymers composed of at least about 75 to a maximum of 90 mole % vinylidene fluoride and correspondingly 10 to 25 mole % hexafluoropropene. Terpolymers of vinylidene fluoride, hexafluoropropene, and tetrafluoroethylene are also representative of the class of vinylidene fluoride copolymers embodied herein.

[0027] In one embodiment, the vinylidene fluoride polymer contains up to 50 wt%, preferably up to 20 wt%, more preferably up to 15 wt% hexafluoropropene (HFP) units, and 50 wt%, preferably 80 wt%, more preferably 85 wt% or more VDF units. To provide a PVDF-HFP copolymer with excellent dimensional stability in end-use environments such as batteries, it is desirable to disperse the HFP units as uniformly as possible.

[0028] The copolymer of PVDF for use in separator coating compositions preferably has a high molecular weight as measured by melt viscosity. High molecular weight means a PVDF having a melt viscosity exceeding 10 kilopoise, preferably exceeding 20 kilopoise, when measured at 232 °C for 100 sec -1 in accordance with ASTM method D-3835.

[0029] Fluoropolymers such as polyvinylidene-based polymers are produced by any process known in the art. Processes such as emulsion and suspension polymerization are preferred and are described in US6187885 and EP0120524.

[0030] Synthetic polyamide Polyamide is a polymer (a substance composed of long, multiple-unit molecules) in which the repeating units of the molecular chain are linked to each other by amide groups. The general chemical formula of the amide group is CO-NH. They may be formed by the interaction of an amine (NH2) group and a carboxyl (CO2H) group, or may be formed by the polymerization of an amino acid or an amino acid derivative (a molecule containing both an amino group and a carboxyl group).

[0031] The synthesis of polyamide is well described in the art, for example, WO15 / 071604, WO14179034, EP0550308, EP0550315, US9637595.

[0032] Polyamide can be the following condensation or ring-opening products: - One or more amino acids such as aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid, or one or more lactams such as caprolactam, enantholactam, and laurolactam; and - One or more salts or mixtures of diamines such as hexamethylenediamine, dodecamethylenediamine, metaxylylenediamine, bis(p-aminocyclohexyl)methane, and trimethylhexamethylenediamine, and diacids such as isophthalic acid, terephthalic acid, adipic acid, azelaic acid, suberic acid, sebacic acid, dodecanedicarboxylic acid.

[0033] Examples of polyamides can include PA6, PA7, PA8, PA9, PA10, PA11, and PA12, as well as copolyamides such as PA6,6.

[0034] Copolyamides are obtained from the condensation of at least two alpha, omega - aminocarboxylic acids or two lactams, or one lactam and one alpha, omega - aminocarboxylic acid. Copolyamides are obtained from the condensation of at least one alpha, omega - aminocarboxylic acid (or one lactam), at least one diamine, and at least one dicarboxylic acid. Examples of lactams include those having 3 to 12 carbon atoms on the main ring, and this lactam can be substituted. For example, there are β,β - dimethylpropiolactam, α,α - dimethylpropiolactam, amylolactam, caprolactam, capryllactam, and laurolactam.

[0035] Examples of alpha, omega - aminocarboxylic acids include aminoundecanoic acid and aminododecanoic acid. Examples of dicarboxylic acids include adipic acid, sebacic acid, isophthalic acid, butanedioic acid, 1,4 - cyclohexanedicarboxylic acid, terephthalic acid, sodium or lithium salts of sulfoisophthalic acid, dimerized fatty acids (these dimerized fatty acids have a dimer content of at least 98% and are preferably hydrogenated), and dodecanedioic acid, and HOOC-(CH2)10-COOH.

[0036] The diamine can be an aliphatic diamine having 6 to 12 carbon atoms. It can be of the aryl and / or saturated cyclic type. Examples include hexamethylenediamine, piperazine, tetramethylenediamine, octamethylenediamine, decamethylenediamine, dodecamethylenediamine, 1,5-diaminohexane, 2,2,4-trimethyl-1,6-diaminohexane, diamine polyol, isophoronediamine (IPD), methylpentamethylenediamine (MPDM), bis(aminocyclohexyl)methane (BACM), and bis(3-methyl-4-aminocyclohexyl)methane (BMACM).

[0037] Examples of copolyamides include: copolymers of caprolactam and lauryllactam (PA6 / 12), copolymers of caprolactam, adipic acid, and hexamethylenediamine (PA6 / 6-6), copolymers of caprolactam, lauryllactam, adipic acid, and hexamethylenediamine (PA6 / 12 / 6-6), copolymers of caprolactam, lauryllactam, 11-aminoundecanoic acid, azelaic acid, and hexamethylenediamine (PA6 / 6-9 / 11 / 12), copolymers of caprolactam, lauryllactam, 11-aminoundecanoic acid, adipic acid, and hexamethylenediamine (PA6 / 6-6 / 11 / 12), and copolymers of lauryllactam, azelaic acid, and hexamethylenediamine (PA6-9 / 12).

[0038] Polyamides also include polyamide block copolymers such as polyether-b-polyamide and polyester-b-polyamide.

[0039] Another polyamide is Arkema's ORGASOL® ultra-fine polyamide 6, 12, and 6 / 12 powders, which are microporous and have closed cells due to their manufacturing process. The particle size range of these powders is very narrow and can be 5 to 60 μm depending on the grade. A lower average particle size of 5 to 20 is preferred.

[0040] Acrylic As used herein, acrylic polymers mean polymers, copolymers, and terpolymers formed from methacrylate and acrylate monomers, and mixtures thereof. The methacrylate monomers and acrylate monomers can constitute 51 to 100% of the monomer mixture, and 0 to 49% of other ethylenically unsaturated monomers including, but not limited to, styrene, alpha-methylstyrene, acrylonitrile can be present. Suitable acrylate and methacrylate monomers and comonomers include, but are not limited to: methyl acrylate, ethyl acrylate and ethyl methacrylate, butyl acrylate and butyl methacrylate, isooctyl methacrylate and acrylate, lauryl acrylate and lauryl methacrylate, stearyl acrylate and stearyl methacrylate, isobornyl acrylate and methacrylate, methoxyethyl acrylate and methacrylate, 2-ethoxyethyl acrylate and methacrylate, dimethylaminoethyl acrylate and methacrylate monomers. (Meth)acrylic acids such as methacrylic acid and acrylic acid can be comonomers. Acrylic polymers typically include multilayer acrylic polymers such as core-shell structures made by emulsion polymerization.

[0041] Styrene As used herein, styrenic polymers mean polymers, copolymers, and terpolymers formed from styrene and alpha-methylstyrene monomers, as well as mixtures thereof. Styrene and alpha-methylstyrene monomers can constitute 50 to 100% of the monomer mixture, and 0 to 50% of other ethylenically unsaturated monomers including but not limited to acrylate, methacrylate, acrylonitrile may be present. Styrene polymers include, but are not limited to: polystyrene, acrylonitrile-styrene-acrylate (ASA) copolymer, styrene acrylonitrile (SAN) copolymer, styrene-butadiene copolymers such as styrene-butadiene rubber (SBR), methyl methacrylate-butadiene-styrene (MBS), and styrene-(meth)acrylate copolymers such as styrene-methyl methacrylate copolymer (S / MMA).

[0042] As used herein, polyolefins mean polyethylene, polypropylene, and copolymers of ethylene and propylene. Ethylene and propylene monomers can constitute 51 to 100% of the monomer mixture, and 0 to 49% of other ethylenically unsaturated monomers including but not limited to acrylate, methacrylate, acrylonitrile, anhydride may be present. Examples of polyolefins include ethylene-ethyl acetate copolymer (EVA), ethylene-(meth)acrylate copolymer, ethylene anhydride copolymer and grafted polymers, propylene-(meth)acrylate copolymer, propylene anhydride copolymer and grafted polymers.

[0043] Solvents useful in the present invention for preparing slurries include, but are not limited to, water, N-methyl-2-pyrrolidone (NMP), toluene, tetrahydrofuran (THF), acetone, and hydrocarbons. In a preferred embodiment, the solvent is NMP, water, or acetone. The solvent must be able to dissolve the polymer used to provide a visibly clear solution. For example, PVDF is soluble in NMP. Since PVDF is insoluble in water, water is not used for PVDF. Polyvinyl alcohol (PVOH), polyacrylamide, carboxymethyl cellulose CMC, polyacrylic acid (PAA), and their copolymers are generally water-soluble.

[0044] Other additives The coating composition of the present invention may further contain an effective amount of other additives (including, but not limited to, fillers, leveling agents, defoaming agents, pH buffers, and other auxiliary components commonly used in formulations) while meeting the desired requirements.

[0045] In the slurry coating composition of the present invention, optionally, a wetting agent, a thickening agent, or a rheology modifier can be included.

[0046] The wetting agent can be present in the coating composition slurry in an amount of 0 to 5 parts (all parts by weight), or 0.1 to 5 parts, preferably 0 to 3 parts, or 0.1 to 3 parts of one or more wetting agents per 100 parts of the solvent. Surfactants can function as wetting agents, but wetting agents can include non-surfactants. In some embodiments, the wetting agent can be an organic solvent. The presence of an optional wetting agent can uniformly disperse the powdery substance in the slurry. Useful wetting agents include, but are not limited to: TRITON (registered trademark) series (manufactured by Dow) and PLURONIC (registered trademark) series (manufactured by BASF), ionic and non-ionic surfactants such as BYK-346 (manufactured by BYK Additives), and organic liquids (NMP, DMSO, and acetone) compatible with the solvent.

[0047] The thickener and / or rheology modifier may be present in the coating composition in an amount of 0 to 10 parts (all in parts by weight), preferably 0 to 5 parts, per 100 parts of water of one or more thickeners or rheology modifiers. When a thickener or rheology modifier is added to the above dispersion, it provides a slurry viscosity suitable for the casting process while preventing or slowing down the sedimentation of the powdery material. In addition to the organic rheology modifier, an inorganic rheology modifier can also be used alone or in combination.

[0048] The ratio of the resin to the total solids and the nanoparticle filler should be selected to produce a slurry with a high yield stress, i.e., higher than 50 dynes / cm 2 and preferably greater than 75 dynes / cm 2 and even more preferably greater than 100 dynes / cm 2 or greater than 200 dynes / cm 2 and even greater. The yield stress is up to 5000 dynes / cm 2 and preferably up to 3000 dynes / cm 2 .

[0049] The solids content of the slurry can be 2 wt% to 30 wt% solids, preferably 2 to 20 wt%, even more preferably 2 to 12 wt%, or 2 to 10 wt% (based on the total weight of the polymer and the nanoparticles).

[0050] Carbon has a high specific surface area, good dispersibility in solvents, and preferably a fractal-shaped structure.

[0051] Several factors can affect the porosity or density of the network film composite material. For example, reducing the solids in the slurry (i.e., from 10% to 6%) results in a few percent higher porosity, and a higher drying temperature (i.e., 180 °C instead of 100 °C) increases the porosity by a few percent. The higher the MW resin, the higher the porosity, and the larger the surface area of the filler, the higher the porosity. By applying all these adjustable properties, a network film composite material with the desired properties for a specific application can be manufactured.

[0052] Use: The network film composite material of the present invention can adjust the hot spots in the device by slowing down the current.

[0053] The network film composite material of the present invention is a very flexible and deformable conductive film for wearable electronic devices or biomedical sensors.

[0054] The network film composite material of the present invention can be used as a diffusion layer of a fuel cell.

[0055] The network film composite material of the present invention can be used as a host for an anode or a cathode of a lithium-ion battery or an electric double-layer capacitor.

[0056] The network film composite material of the present invention can be used as an electromagnetic interference, EMI, or radio frequency interference, RFI, shield.

[0057] The network film composite material of the present invention can be used as a catalyst carrier.

[0058] The network film composite material not only does not shrink at high temperatures, but can also be adjusted to expand at the hot spots in the device to slow down the current.

[0059] Another advantage of the network film composite material is that it can be cast on different surfaces and can function as a conductive network. The highly flexible and deformable conductive film is useful for wearable electronics and biomedical sensors.

[0060] As another example, a network film composite material of PVDF and conductive carbon with a porosity of 50% can be used for energy storage, for example, as a bipolar plate coating, or as a diffusion layer of a fuel cell, or as a host for an anode or cathode of a lithium-ion battery, and can provide a long cycle life (i.e., a lithium-sulfur battery). Since the composite material of the present invention has a very large surface area, it can also be used as a highly efficient electrode of an electric double layer capacitor.

[0061] As another example, a network film composite material of PVDF and conductive carbon with a porosity of 50% can be used as a gas diffusion layer, which is a main component of various types of fuel cells including proton exchange membrane (PEM), direct methanol (DMFC), and phosphoric acid (PAFC) stacks. The gas diffusion layer is disposed on both sides of the fuel cell membrane to allow reactants such as H2, air / oxygen, methanol, and product gas to flow uniformly.

[0062] The network film composite of the present invention, especially PVDF, has ultraviolet and radiation resistance, and thus can have other applications such as effective lightweight electromagnetic interference (EMI), or radio frequency interference (RFI) shielding or shielding gaskets used in electronics, especially in aeronautics.

[0063] The network film composite material can also provide a high surface medium for catalytic-driven reactions and can be used as a catalyst carrier to improve catalytic efficiency. The catalyst can be incorporated into the network film or deposited thereon.

[0064] Use: The response to temperature can be adjusted with the resin composition. For example, a network film composite material made of a resin with a higher HFP (i.e., 20% HFP) content may require a higher temperature to obtain the same swelling / expansion, and thus swells / expands at a lower temperature compared to one with a lower HFP (i.e., 8% HFP) content. Therefore, the amount of HFP comonomer in the PVDF resin is changed. The preferred weight percent of HFP in the copolymer of VDF is 1 to 25 weight percent, although higher weight percents (up to 50 weight percent) of HFP can be used.

[0065] The coating can be cast onto a substrate, removed from the substrate and placed onto another substrate, or cast in combination with another layer in a wet-on-wet process.

[0066] Another advantage of the network film composite material is that it can be cast simultaneously with another layer, i.e., using a double slot die casting machine, two slurry layers can be cast simultaneously using wet-on-wet technology. The integrated structure is then formed during the drying and calendaring steps. In the case of a multilayer composite structure such as an electrode separator for an electrochemical device or a filter medium, it can be cast wet-on-wet. Using wet-on-wet technology, the two layers are intertwined, there is no sharp interface, and the adhesion is improved. The network film or coating can be cast directly onto the substrate simultaneously with the substrate in one step of the wet-on-wet process.

[0067] Coating In one embodiment, the carbon-based nanoparticles or fibers can be surface-treated chemically (such as by etching or functionalization), mechanically, or by irradiation (such as by plasma treatment).

[0068] The particles are nano-sized. Preferably, the fibers have a diameter of less than 1 μm.

[0069] Based on the total of the polymer solid and the carbon-based nanoparticles, the carbon-based nanoparticles are present in the coating composition at 20 to 95% by weight, preferably 20 to 90% by weight. When the content of the carbon-based nanoparticles is less than 20% by weight, the binder polymer will be present in such a large amount as to reduce the interstitial volume formed between the particles.

[0070] In another example, a network film composite material can be used as a protective coating, i.e., when nano-sized ZnO or nano-TiO2 is included, it exhibits high UV blocking / protection.

[0071] The network film composite material can also provide a high surface area medium for catalytically driven reactions and can be used as a catalyst support to improve catalytic efficiency. The catalyst can be incorporated into the network film or deposited thereon.

[0072] Coating Method The coating composition can be applied to at least one surface of the substrate by means known in the art such as brushes, rollers, inkjets, dips, knives, gravures, wires, squeegees, foam applicators, curtain coating, vacuum coating, slot dies or sprays. Next, the coating is dried on the substrate at room temperature or at an elevated temperature. The thickness of the final dry coating is from 0.5 to 500 μm, preferably from 1 to 100 μm, more preferably from 2 to 50 μm.

[0073] In some aspects, the network film composite material can be cast simultaneously with another layer.

[0074] Aspects of the Invention Aspect 1: a network coating or film comprising a) a resin and b) nanoparticles, The coating or film has a porous structure, the porous structure consists of 10% - 80% continuous pores, the solution viscosity of the resin is about 100 cp - 10,000 cp, preferably 100 cp - 5000 cp (5 wt% in NMP, 2% water in the case of aqueous polymer, measured at room temperature), the nanoparticles are carbon-based with a surface area of 1 - 10000 m 2 / g, preferably 1 - 5000 m 2 / g, preferably 1 - 1000 m 2 / g, and the film is a reticulated coating or film that shows a recovery of at least 30%, preferably 50%, preferably 55%, preferably 60%, preferably 70% in thickness or porosity after being compressed and then heated. Aspect 2: The reticulated coating or film according to Aspect 1, wherein the average pore size is less than 500 nm, preferably less than 100 nm, more preferably less than 50 nm. Aspect 3: The reticulated coating or film according to Aspect 1 or 2, wherein the resin is selected from the group consisting of: polyvinylidene fluoride (PVDF), PVDF copolymer, polyethylene tetrafluoride ethylene (PETFE), polyvinyl fluoride (PVF), polyacrylate, polymethacrylate, polystyrene, polyvinyl alcohol (PVOH), polyester, polyamide, polyacrylonitrile, polyacrylamide, carboxymethyl cellulose CMC, polyacrylic acid (PAA), polymethacrylic acid (PMAA), and their copolymers, and combinations thereof. Aspect 4: The reticulated coating or film according to any one of Aspects 1 - 3, wherein the resin contains a homopolymer or copolymer of polyvinylidene fluoride. Aspect 5: The reticulated coating or film according to any one of Aspects 1 - 3, wherein the resin contains polymethacrylate. Aspect 6: The reticulated coating or film according to any one of Aspects 1 - 3, wherein the resin contains carboxymethyl cellulose. Aspect 7: The reticulated coating or film according to any one of Aspects 1 - 3, wherein the resin contains polyacrylic acid and / or polymethacrylic acid. Side 8: The nanometer particles are the network coating or film according to any one of sides 1 to 7, selected from the group consisting of graphene, carbon nanotubes, conductive carbon, activated carbon, and mixtures thereof. Side 9: The nanometer particles contain conductive carbon, and are the network coating or film according to any one of sides 1 to 7. Side 10: The nanometer particles contain activated carbon, and are the network coating or film according to any one of sides 1 to 7. Side 11: The weight percentage ratio of the polymer to the nanometer particles is 80:20 to 10:90, preferably 70:30 to 20:80, and is the network coating or film according to any one of sides 1 to 10. Side 12: The surface area of the nanometer particles is 1 to 700 m 2 / g, more preferably 1 to 600 m 2 / g, and is the network coating or film according to any one of sides 1 to 11. Side 13: The coating has a thickness of 0.1 to 500 μm, preferably 0.5 to 100 μm, more preferably 0.5 to 50 μm, and even more preferably 0.5 to 20 μm, and is the network coating or film according to any one of sides 1 to 12. Side 14: The size of the nanometer particles is less than 500 nm, preferably less than 200 nm, and is the network coating or film according to any one of sides 1 to 13. Side 15: The size of the nanometer particles is less than 100 nm, and is the network coating or film according to any one of sides 1 to 13. Side 16: A method for producing a network coating or film, the method comprising the following steps: Providing a resin dissolved in a solvent (wherein the polymer has a molecular weight such that the solution viscosity is about 100 cp to 10,000 cp, preferably 100 cp to 5,000 cp (5 wt% in NMP, 2 wt% water in the case of an aqueous polymer solution, measured at room temperature)); Providing nanometer particles (wherein the surface area of the nanometer particles is 1 to 10,000 m 2 / g); Combining the resin solution and the nanoparticles to produce a slurry (where the ratio of the weight percentage of the polymer to the weight percentage of the nanoparticles is 80:20 to 5:95); Casting the slurry to form a coating or film; Drying the formed coating or film comprising The dried coating or film has a porous structure, and the porous structure is composed of 10% to 80% continuous pores, The slurry has a yield stress of 50 dyn / cm 2 to 5000 dyn / cm 2 preferably 75 to 3000 dyn / cm 2 and the solid content of the slurry is 2 to 30% by weight, preferably 2 to 20% by weight. After the film is compressed and then heated, it shows a recovery of at least 30%, preferably 50%, preferably 55%, preferably 60%, preferably 70% in thickness or porosity. A method. Aspect 17: The method according to aspect 16, wherein the average pore size is less than 1000 nm. Aspect 18: The method according to aspect 16, wherein the average pore size is less than 100 nm, more preferably less than 10 nm. Aspect 19: The method according to any one of aspects 16 to 18, wherein the resin is selected from the group consisting of: polyvinylidene fluoride (PVDF), PVDF copolymer, polyethylene tetrafluoride ethylene (PETFE), polyvinyl fluoride (PVF), polyacrylate, polymethacrylate, polystyrene, polyvinyl alcohol (PVOH), polyester, polyamide, polyacrylonitrile, polyacrylamide, carboxymethyl cellulose CMC, polyacrylic acid (PAA), polymethacrylic acid (PMAA), and copolymers thereof, and combinations thereof. Aspect 20: The method according to any one of aspects 16 to 18, wherein the resin comprises a homopolymer or copolymer of polyvinylidene fluoride. Side 21: The resin contains polymethacrylate, and the method according to any one of aspects 16 to 18. Side 22: The resin contains carboxymethyl cellulose, and the method according to any one of aspects 16 to 18. Side 23: The resin contains polyacrylic acid and / or polymethacrylic acid, and the method according to any one of aspects 16 to 18. Side 24: The nanoparticles are selected from the group consisting of graphene, carbon nanotubes, conductive carbon, activated carbon, or mixtures thereof, and the method according to any one of aspects 16 to 23. Side 25: The nanoparticles contain conductive carbon or activated carbon, and the method according to any one of aspects 16 to 23. Side 26: The nanoparticles contain graphene or carbon nanotubes, and the method according to any one of aspects 16 to 23. Side 27: The solvent is selected from the group consisting of water, N-methyl-2-pyrrolidone (NMP), toluene, tetrahydrofuran (THF), acetone, and hydrocarbons, and the method according to any one of aspects 16 to 26. Side 28: The solvent is selected from the group consisting of NMP, water, acetone, and combinations thereof, preferably NMP, and the method according to any one of aspects 16 to 26. Side 29: The solvent contains water, and the method according to any one of aspects 16 to 26. Side 30: The solvent contains NMP, and the method according to any one of aspects 16 to 26. Side 31: The solid content of the formed slurry containing both the solvent and the nanoparticles is 2 to 15% by weight, and the method according to any one of aspects 16 to 30. Side 32: The solid content of the formed slurry containing both the solvent and the nanoparticles is 2 to 12% by weight, and the method according to any one of aspects 16 to 30. Side 33: The weight percentage ratio of the polymer to the nanoparticles is 80:20 to 10:90, and the method according to any one of aspects 16 to 32. Side 34: The method according to any one of sides 16 to 32, wherein the weight percentage ratio of the polymer to the nanoparticles is from 70:30 to 20:80. Side 35: The surface area of the nanoparticles is 1 to 700 m 2 / g, more preferably 1 to 600 m 2 / g, and the method according to any one of sides 16 to 34. Side 36: The method according to any one of sides 16 to 34, wherein the coating has a thickness of 0.1 to 100 μm, preferably 0.5 to 50 μm, more preferably 0.5 to 20 μm. Side 37: The method according to any one of sides 16 to 36, wherein the size of the nanoparticles is less than 500 nm, preferably less than 200 nanometers. Side 38: The method according to any one of sides 16 to 36, wherein the size of the nanoparticles is less than 100 nm. Side 39: The method according to any one of sides 16 to 36, wherein the film shows a recovery of at least 55%, preferably at least 60% in thickness or porosity after being compressed and then heated. Side 40: The method according to any one of sides 16 to 39, wherein the mesh film or coating is directly cast simultaneously with the substrate in one step of a wet-on-wet process. Side 41: A mesh coating or film produced by the method according to any one of sides 16 to 40. Side 42: An article comprising the mesh coating or film according to any one of sides 1 to 15 and 41, wherein the article is selected from the group consisting of a separator for a wearable electronic device or a biomedical sensor, a diffusion layer of a fuel cell, an anode or a cathode of a lithium ion battery or an electric double layer capacitor, an electromagnetic interference, EMI, or a radio frequency interference, RFI, shield, and a catalyst support, and the article is an electrochemical device. Side 42: An article comprising the mesh coating or film according to any one of sides 1 to 15 and 41, and the article comprises an electrochemical device. Side 43: An article comprising the reticulated coating or film according to any one of sides 1 to 15 and 41, the article comprising a diffusion layer of a fuel cell. Side 44: An article comprising the reticulated coating or film according to any one of sides 1 to 15 and 41, the article comprising a diffusion layer of a catalyst support.

[0075] Test method The melt viscosity to be measured is 100 sec at 232 °C according to ASTM method D - 3835 -1 measured at.

[0076] The particle size of the nanoparticles can be measured using a Malvern Masturizer 2000 particle size analyzer. The data is shown as the weight - average particle size (diameter).

[0077] The powder / latex average discrete particle size can be measured using a NICOMP TM 380 sub - micron particle size analyzer using laser light scattering. The data is shown as the weight - average particle size (diameter).

[0078] The density of the composite material was calculated by dividing the weight of the composite material by the volume of a specific sample. First, the composite material was cast onto aluminum foil, and then a sample with a surface area of 1.33 cm 2 was created by stamp - cutting the cast composite material. The thickness of the sample was measured with a micrometer having an accuracy of 0.1 μm. The weight of the composite material was measured using an analytical balance, and the weight of the aluminum foil was subtracted. The density of the solid materials is based on published literature values. That is, PVDF polymer = 1.78 g / cm 3 , PMMA = 1.13 g / cm 3 , CMC = 1.6 g / cm 3 is.

[0079] The BET specific surface area, pore volume, and pore size distribution of the material can be determined using a QUANTACHROME NOVA-E gas sorption apparatus. The isotherms of nitrogen adsorption and desorption are generated at 77 K. The multi-point Brunauer-Emmett-Teller (BET) nitrogen adsorption method is used to specify the specific surface area. The nonlocal density functional theory (Nonlocal Density Functional Theory, NLDFT, N2, 77k, slit pore model) is used to specify the pore volume and pore size distribution.

[0080] Solution viscosity: ASTM2857

[0081] Yield stress back-calculation: Brookfield viscometer DV-III Ultra, spindle CP52 calculation based on the Herschel-Bulkley model equation:

Number

[0082] τ is the shear stress. To obtain the viscosity, it is necessary to divide by the shear rate. The calculation is as follows.

Number

[0083] In the formula, since k is expressed in Centipoise, it needs to be divided by 100 to D / cm 2 and it is necessary to add it to τ°. When calculating τ° inversely, the equation becomes as follows.

Number

[0084] Volume resistivity measurement: The slurry was cast onto an aluminum foil with a thickness of about 110 μm and placed in a convection oven at 120 °C for 30 minutes. Next, an Instron testing machine was used together with a gold-plated electrode of 3.09 cm 2 to obtain the resistivity under various compressive forces. The circular gold-coated contacts were adhered to the Instron fixture using 3M double-sided tape. The resistance was measured using a Yokogawa digital resistor meter (755601, 4-probe). The contact pressure was applied at a rate of 20 N / min using an Instron (500 N load cell). All data were recorded manually. The resistivity decreased with pressure and reached a plateau at about 100 N.

Number

Example

[0085] Example 1: Using different conductive carbons and fumed alumina as a control, recovery from compression after calendaring of a reticulated film composite material of a PVDF / HFP and 50 wt% HFP and PMMA (RV = 1.1 dl / g) resin PVDF (Kynar 1810) copolymer.

[0086]

Table 1

[0087] This indicates that recovery was observed for carbon-based materials but not for Al2O3. Upon heating, a recovery exceeding 30% of the original volume was observed.

[0088] Example 2: Effect of temperature on the reticulated film composite material:

[0089]

Table 2

[0090] This indicates that a porosity exceeding 50% or the original porosity recovers upon heating.

[0091] Resistivity measurement: The slurry was composed of NMP (manufactured by Aldrich), conductive carbon super-P (manufactured by Timcal), and three different PVDF resins including Kynar® HSV-900 (manufactured by Arkema), Solef-5130 (manufactured by Solvay), and Kynar® HSV-1810 (manufactured by Arkema). The three composite materials were cast on aluminum foil and subsequently dried in a convection oven at 120 °C. The resulting composite materials showed the following volume resistivity.

[0092]

Table 3

[0093] The reproducibility of resistivity measurement seems to be relatively good, and a difference exceeding 100 (Ω·cm) should be regarded as significant.

Claims

1. a reticulated coating or film comprising a) a resin and b) nanoparticles, The net coating or film has a continuous porous structure, the porous structure being continuous pores of 10% to 80% by volume, the solution viscosity of the resin being about 100 cp to 10,000 cp, preferably 100 cp to 5000 cp (5 wt% in NMP, 2 wt% in the case of an aqueous polymer solution, measured at room temperature), the nanoparticles being carbon-based with a surface area of 1 to 10000 m 2 / g, preferably 1 to 5000 m 2 / g, preferably 1 to 1000 m 2 / g, and the film is a net coating or film that exhibits a recovery of at least 30%, preferably 50%, preferably 55%, preferably 60%, preferably 70% in thickness or porosity after being compressed and then heated.

2. The reticulated coating or film according to claim 1, wherein the resin is selected from the group consisting of: polyvinylidene fluoride (PVDF), PVDF copolymer, polyethylene tetrafluoroethylene (PETFE), polyvinyl fluoride (PVF), polyacrylate, polymethacrylate, polystyrene, polyvinyl alcohol (PVA), polyester, polyamide, polyacrylonitrile, polyacrylamide, carboxymethyl cellulose CMC, polyacrylic acid (PAA), polymethacrylic acid (PMAA), and copolymers thereof, and combinations thereof.

3. The reticulated coating or film according to claim 1 or 2, wherein the average pore size is less than 500 nm, preferably less than 100 nm, more preferably less than 50 nm.

4. The reticulated coating or film according to claim 1, wherein the resin comprises a homopolymer or copolymer of polyvinylidene fluoride.

5. The reticulated coating or film according to claim 1, wherein the resin comprises polymethacrylate.

6. The reticulated coating or film according to claim 1, wherein the resin comprises carboxymethyl cellulose.

7. The reticulated coating or film according to claim 1, wherein the resin comprises polyacrylic acid and / or polymethacrylic acid.

8. The reticulated coating or film according to claim 1 or 2, wherein the nanoparticles are selected from the group consisting of graphene, carbon nanotubes, conductive carbon, activated carbon, and mixtures thereof.

9. The reticulated coating or film according to claim 1 or 2, wherein the nanoparticles comprise conductive carbon.

10. The reticulated coating or film according to claim 1 or 2, wherein the nanoparticles comprise activated carbon.

11. The reticulated coating or film according to claim 1 or 2, wherein the weight percentage ratio of polymer to nanoparticles is 80:20 to 10:90, preferably 70:30 to 20:

80.

12. The surface area of the nanoparticles is 1 to 700 m 2 / g, more preferably 1 to 600 m 2 / g, the network coating or film according to claim 1 or 2.

13. The reticulated coating or film according to claim 1 or 2, wherein the coating has a thickness of 0.1 to 500 μm, preferably 0.5 to 100 μm, more preferably 0.5 to 50 μm, even more preferably 0.5 to 20 μm.

14. The reticulated coating or film according to claim 12, wherein the size of the nanoparticles is less than 500 nm, preferably less than 200 nm.

15. The reticulated coating or film according to claim 12, wherein the size of the nanoparticles is less than 100 nm.

16. A method for producing a reticulated coating or film, the method comprising the following steps: a) providing a resin dissolved in a solvent, wherein the polymer has a solution viscosity of about 100 cp to 10,000 cp, preferably 100 cp to 5,000 cp (5 wt% in NMP, 2 wt% water in the case of an aqueous polymer solution, at room temperature); b) providing nanoparticles, wherein the surface area of the nanoparticles is from 1 to 10,000 m 2 / g); c) combining the resin solution and the nanoparticles to produce a slurry, wherein the ratio of the weight percentage of the polymer to the weight percentage of the nanoparticles is 80:20 to 5:95; d) casting the slurry to form a coating or film on a substrate; e) drying the formed coating or film and the dried coating or film has a porous structure, and the porous structure is composed of 10% to 80% by volume of continuous pores. The slurry has a yield stress of 50 dynes / cm 2 to 5000 dynes / cm 2 , preferably 75 to 3000 dynes / cm 2 and the solids content of the slurry is 2 to 30% by weight of solids, preferably 2 to 20% by weight of solids, and the film shows a recovery of at least 30%, preferably 50%, preferably 55%, preferably 60%, preferably 70% of its thickness or porosity after being compressed and then heated.

17. The method according to claim 16, wherein the average pore size is less than 1000 nm.

18. The method according to claim 16, wherein the average pore size is less than 100 nm, more preferably less than 10 nm.

19. The method according to claim 16 or 17, wherein the resin is selected from the group consisting of polyvinylidene fluoride (PVDF), PVDF copolymer, polyethylene tetrafluoroethylene (PETFE), polyvinyl fluoride (PVF), polyacrylate, polymethacrylate, polystyrene, polyvinyl alcohol (PVA), polyester, polyamide, polyacrylonitrile, polyacrylamide, carboxymethyl cellulose CMC, polyacrylic acid (PAA), polymethacrylic acid (PMAA), and copolymers thereof, and combinations thereof.

20. The method according to claim 16 or 17, wherein the resin comprises a homopolymer or copolymer of polyvinylidene fluoride.

21. The method according to claim 16 or 17, wherein the resin comprises polymethacrylate.

22. The method according to claim 16 or 17, wherein the resin comprises carboxymethyl cellulose.

23. The method according to claim 16 or 17, wherein the resin contains polyacrylic acid and / or polymethacrylic acid.

24. The method according to claim 19, wherein the nanoparticles are selected from the group consisting of graphene, carbon nanotubes, conductive carbon, activated carbon, or a mixture thereof.

25. The method according to claim 16 or 17, wherein the nanoparticles contain conductive carbon or activated carbon.

26. The method according to claim 16 or 17, wherein the nanoparticles contain graphene or carbon nanotubes.

27. The method according to claim 26, wherein the solvent is selected from the group consisting of water, N-methyl-2-pyrrolidone (NMP), toluene, tetrahydrofuran (THF), acetone, and hydrocarbons.

28. The method according to claim 24, wherein the solvent is selected from the group consisting of NMP, water, acetone, and combinations thereof, preferably NMP.

29. The method according to claim 24, wherein the solvent contains water.

30. The method according to claim 24, wherein the solvent contains NMP.

31. The method according to claim 24, wherein the solid content of the formed slurry containing both the solvent and the nanoparticles is 2 to 30%, preferably 2 to 15% by weight.

32. The method according to claim 24, wherein the solid content of the formed slurry containing both the solvent and the nanoparticles is 2 to 12% by weight.

33. The method according to claim 16 or 17, wherein the weight percentage ratio of the polymer to the nanoparticles is 80:20 to 10:

90.

34. The method according to claim 16 or 17, wherein the weight percentage ratio of the polymer to the nanoparticles is 70:30 to 20:

80.

35. The surface area of the nanoparticles is 1 to 700 m 2 / g, more preferably 1 to 600 m 2 / g, the method according to claim 16 or 17.

36. The method according to claim 16 or 17, wherein the coating has a thickness of 0.1 to 100 μm, preferably 0.5 to 50 μm, more preferably 0.5 to 20 μm.

37. The method according to claim 24, wherein the size of the nanoparticles is less than 500 nm, preferably less than 200 nanometers.

38. The method according to claim 16 or 17, wherein the size of the nanoparticles is less than 100 nm.

39. The method according to claim 16 or 17, wherein the film shows a recovery of at least 55%, preferably at least 60% in thickness or porosity after being compressed and then heated.

40. The method according to claim 16 or 17, wherein the mesh film or coating is directly cast simultaneously with the substrate in one step of a wet-on-wet process.

41. A mesh coating or film produced by the method according to any one of claims 16 to 40.

42. An article comprising a mesh coating or film according to any one of claims 1 to 15 and 41, wherein the article is selected from the group consisting of a separator for a wearable electronic device or a biomedical sensor, a diffusion layer of a fuel cell, an anode or a cathode of a lithium ion battery or an electric double layer capacitor, an electromagnetic interference, EMI, or a radio frequency interference, RFI, shield, and a catalyst support, and the like, an article.

43. An article comprising a mesh coating or film according to any one of claims 1 to 15 and 41, the article comprising an electrochemical device.

Images