Method for forming a metallic coating from a metallization liquid

Abstract

A method for forming a metallic coating from a metallization liquid, the metallization liquid comprising at least one metal ionic precursor, at least one structuring liquid, at least one propelling liquid. The at least one metal ionic precursor comprises at least one metal cation and at least one counterion, the at least one structuring liquid for dissolving the at least one metal ionic precursor in the metallization liquid, the at least one propelling liquid for nebulizing the metallization liquid. The method comprises applying the metallization liquid on a substrate, and exposing the metallization liquid to a plasma at atmospheric conditions, thereby obtaining the metallic coating.

Description

DescriptionMethod for forming a metallic coating from a metallization liquid

[0001] This application claims priority of German patent application DE 10 2024 104 886.7, filed on 21 February 2024. The entire disclosure of the German patent application DE 10 2024 104 886.7 is hereby incorporated herein by reference.Field of the Invention

[0002] The invention comprises a method for forming a metallic coating from a metallization liquid, a metallization liquid and a metallic coating.Background of the Invention

[0003] Thin polycrystalline metallic coatings, i.e., films, are components comprised in many applications, such as catalytic surfaces, electrolyzers, batteries, solar cells, fuel cells, electronic devices, touchscreens and others. Currently, the field of surface metallization or metallic coatings is dominated by plating or vapor deposition techniques, as disclosed by Jiri George Drobny, in 4 - Processing Methods Applicable to Thermoplastic Elastomers, Handbook of Thermoplastic Elastomers (Second Edition), William Andrew Publishing, 2014, pages 33-173, ISBN 9780323221368, https: / / doi.org / 10.1016 / B978-0-323-22136- 8.00004-1. These techniques require high material costs, expensive equipments and, in many cases, leave chemical waste.

[0004] US 2023 / 0220230 Al discloses a metallic coating as a conductive laminate having a volume resistivity and excellent heat dissipation properties. The conductive laminate comprises a base material and a conductive ink film (a metallization liquid) on the base material. The conductive ink is an ink containing metal particles, an ink containing a metal complex, or an ink containing a metal salt. The metal particle ink is, for example, an ink composition obtained by dispersing metal particles in a dispersion medium. The dispersion medium comprises, for example, 2-propanol, propylene glycol monomethyl ether, and ethylene glycol monopropyl ether. One example of the metal salt is a silver nitrate. US 2023 / 0220230 Al further discloses a method for forming the metallic coating as the conductive ink film using the metallization coating. The conductive ink film is formed, for example, by applying the conductive ink onto the base material, and then baking the conductive ink applied onto the base material. The conductive ink film may be formed byrepeating the application of the conductive ink and the baking of the conductive ink film multiple times.

[0005] EP 3 887 463 Bl discloses a method for growing a transparent conductive metal layer as a metallic coating on a substrate. The method comprises the steps of applying crystal growth ink to the surface of the substrate. The crystal growth ink comprises a metal ionic precursor as a metallization liquid. The method further comprises exposing the substrate to plasma irradiation to cause the growing of a crystalline metal framework on the substrate. The exposure is based on a set of predefined exposure parameters. The method of EP 3 887 463 Bl further discloses that the step of exposing the substrate to plasma irradiation is conducted in a vacuum chamber to cause the growing of the crystalline metal framework, i.e., layer, on the substrate. In other words, the method of EP 3 887 463 Bl is a chamberbased, non-atmospheric, plasma process. The step of exposing in EP 3 887 463 Bl is conducted at a gas flow rate of 20 SCCM to 50 SCCM, i.e., 0.02 to 0.05 liters / minute and for an exposure time of between 2 minutes and 15 minutes, i.e., 120 seconds and 900 seconds.

[0006] WO 2015 / 071746 Al discloses a method and a device for generating a plasma at atmospheric pressure and low-temperature conditions. The method comprises flowing a process gas that advances in a flow direction through a tubular duct made of dielectric material with an inlet section and an outlet section at atmospheric pressure and positioning a first pair of coaxial electrodes and a second pair of coaxial electrodes in contact with the external surface of said tubular duct. The first pair of electrodes is placed in position upstream of said second pair of electrodes in relation to the flow direction of the gas within said tubular duct and is connected to a high-frequency generator. The second pair of electrodes is connected to a Radio-Frequency (RF) generator. The high-frequency generator generates a filamentary plasma within the tubular duct and the filamentary plasma extends at least to the second pair of electrodes. The Radio-Frequency generator generates a second RF plasma. The method further comprises flowing out the RF plasma and the filamentary plasma to outside of the tubular duct through the outlet section, such plasmas at the outlet comprising at least one neutral gas at the outlet having temperature not higher than about 100°C.

[0007] The Applicant’s own application WO 2016 / 064858 teaches a method and system for forming a thin patterned metal film on a substrate. The method includes applying an inkcomposition on a pre-treated surface of the substrate and exposing at least the applied ink composition on the substrate to a low-energy plasma, The ink composition includes at least metal cations and the low-energy plasma is an inert gas plasma operated according to a first set of exposure parameters, such as radio frequency, power, gas flow and exposure time. The ink composition 130 is applied on the substrate 110 means including, but not limited to, drop-casting, spin-coating, spray-coating, immersion, flexography, gravure, inkjet printing, aerosol jet printing, contact imprinting, and the like.

[0008] WO 2020 / 0115680 teaches a method for growing a transparent conductive metal layer on a substrate. The method includes the steps of applying crystal growth ink to a surface of the substrate and exposing the substrate to plasma irradiation to cause the growing of a crystalline metal framework on the substrate. The crystal growth ink includes a metal ionic precursor, and the exposure is based on a set of predefined exposure parameters.

[0009] WO 2018 / 140430 teaches a method for forming a crystalline metal layer on a three- dimensional (3D) substrate. The method includes applying crystal growth ink to a surface of the 3D substrate and exposing the 3D substrate to plasma irradiation from plasma in a vacuum chamber to cause the growing of a crystalline metal layer on the 3D substrate. The crystal growth ink includes a metal ionic precursor and a structuring liquid.

[0010] WO 2021 / 0477761 teaches processes and an apparatus for atmospheric pressure plasma jet deposition onto a substrate. The process comprises feeding a solution comprising a dissolved metal precursor into a plasma jet. The dissolved metal precursor comprises a precursor metal selected from Groups 2 to 16, with the proviso that the precursor metal does not comprise Mn. The plasma jet is directed towards a surface of the substrate such that material from the plasma jet becomes deposited onto the surface of the substrate. The process provides a means to manufacture conductive, semiconducting or insulating deposits on a substrate in a material-efficient manner without the need for high-temperature post-treatment steps.Summary of the Invention

[0011] A method for forming a metallic coating from a metallization liquid is taught in this disclosure.

[0012] The metallization liquid comprises at least one metal ionic precursor, at least one structuring liquid, at least one propelling liquid. The term “metallization liquid” refers to an ink formulation, an ink composition, or an ink.

[0013] The at least metal ionic precursor is a solid. The at least metal ionic precursor further comprises at least one metal cation and at least one counterion.

[0014] The term “structuring liquid”, i.e., a stabilizing liquid, is for dissolving the at least one metal ionic precursor in the metallization liquid. The at least one structuring liquid may improve solidification of the metallization liquid. The at least one structuring liquid may further improve crystallization, i.e., formation of crystals, of the metallization liquid. The at least one structuring liquid may further change a shape of the crystals of the metallization liquid.

[0015] The term “propelling liquid” is for nebulizing the metallization liquid, i.e., the ink, preferably through a nebulizing generator.

[0016] The method comprises applying the metallization liquid on a substrate, and exposing the metallization liquid to a plasma at atmospheric conditions, thereby obtaining the metallic coating.

[0017] In one aspect, the metallization liquid has a thickness on a substrate, and the applying of the metallization liquid on the substrate is conducted such that the thickness of the metallization liquid is at most 2 mm.

[0018] The metallization liquid may in one aspect comprise the at least one metal ionic precursor at a concentration between 0.01 wt.% and 30 wt.% with respect to the at least one structuring liquid and the at least one propelling liquid. The at least one structuring liquid and the at least one propelling liquid comprise solvents that are substantially quickly decomposed by a plasma at atmospheric conditions, i.e., the metallization liquid is converted into the metallic coating as the metallization liquid interacts with the plasma at atmospheric conditions. The conversion from the metallization liquid to the metallic coating is completed, for example, in less than 10 seconds. The at least one structuring liquid and the at least one propelling liquid are substantially nebulized.

[0019] The term “nebulizing” encompasses both aerosolizing and vaporizing. Aerosolizing refers to suspending particles and / or droplets in a stream of gas. Vaporizing is a phase transition of an element from the liquid phase to the vapor phase.

[0020] The term “nebulizing generator” refers to a system comprising one of an aerosol generator, a vapor generator, or a combination thereof. The aerosol generator is, for example, an atomizer, but this is not limiting of the invention. The vapor generator is, for example, a bubbler, or a bubbler-based chemical vapor generator, but this is not limiting of the invention.

[0021] In one aspect, the at least one structuring liquid may be a solvent. The solubility of the at least one metal ionic precursor in the solvent is at least 15 mg / ml at 25°C, preferably of at least 50 mg / ml at 25°C, more preferably of at least 100 mg / ml at 25°C.

[0022] In one aspect, the at least one propelling liquid may be selected from one of solvents having dynamic viscosity at 25°C of between 0.5 mPa.s and 5 mPa.s.

[0023] In one aspect, the at least one metal cation from any one of Au, Ag, Pt, Pd, Cu, Ti, Nb, Ni, Co, Ru, Ir, and Rh may be selected in view of the use, i.e., the final application, of the metal coating. The at least one metal cation is, in a further aspect, Ag and / or Cu, to obtain a conductive metal coating. The at least one metal cation is, in a further aspect, Au and / or Pt, for use in sensing activity and / or in catalytic activity, such as in hydrogen oxidation reaction, oxygen reduction reaction, and CO2 fixation. The at least one metal cation is, in a further aspect, Pd, to obtain a metallic coating for use in plating as a seed layer. The at least one metal cation is, in a further aspect, Ti and / or Nb, to obtain a metallic coating for use in dielectrics.

[0024] The step of “applying the metallization liquid on the substrate” refers to depositing or printing the metallization liquid on the substrate.

[0025] Using a plasma in the step of exposing enables conduction of a chemical reaction between the metallization liquid and the plasma without exposing the surface of the substrate to high temperatures. The exposing to high temperatures may otherwise damage or harm the surface of the substrate or layers below the surface of the substrate, wherein the substrate is a multi-layer substrate.

[0026] The step of exposing the metallization liquid to the plasma at atmospheric conditions requires a substantially high gas flow rate. However, the substantially high gas flow rate may be compensated by substantially low exposure time. In other words, generating a plasma at atmospheric conditions require a higher concentration of plasma than generating a plasma under vacuum. The generation of plasma at atmospheric conditions is faster than generating plasma under vacuum.

[0027] The method may be used to obtain, i.e., produce, fine-pattern structures, such as structures of tens of micron, in the metallic coating. The method may comprise printing the fine-pattern structures with a high-resolution printer, such as a printer comprising a precision of 20-30 micrometers. The obtention of the fine-pattern structures illustrates that the method enables a spatial control, i.e., to be conducted in a controlled manner.

[0028] In one aspect, the applying of the metallization liquid on the substrate is conducted with a first machine, such as a printer. The exposing of the metallization liquid to the plasma at atmospheric conditions is conducted with a second machine, such as an atmospheric plasma generator. The method is referred to as a two-stage method.

[0029] In a further aspect, the method comprises nebulizing the metallization liquid, exposing the metallization liquid to the plasma at atmospheric conditions, and applying the resulting nebulized metal on the substrate. The nebulizing of the liquid enables simultaneous deposition and metallization. The nebulization enables high precision and speed of the deposition. The difference here between nebulizing and spray-coating is in that, first, spray coating is an umbrella term for many various coating approaches and, as such, is not specific enough. Nebulization allows for precise control over the droplet size and, in turn, gives control over the reaction kinetics.

[0030] The step of nebulizing and the step of exposing are conducted, in a further aspect, in the nebulizing generator, so that the metallic coating is obtained in one production stage. In other words, the nebulizing generator enables nebulizing the metallization liquid and exposing the metallization liquid to the plasma at atmospheric conditions. The method is referred to as a one-stage method.

[0031] In one aspect, the two-stage method enables applying precisely the metallization liquid compared to the one-stage method. In a further aspect, the one-stage method enables applying the metallization liquid on substantially high surfaces of the substrate compared to the two-stage method. The one-stage method is further easier to scale than a two-stage method. The one-stage method further enables to be used for forming metallic coating on three-dimensional (3D) substrates and does not require flat two-dimensional substrates. The one-stage method and the two-stage method are substantially fast compared to plating techniques and vapor deposition techniques.Description of the Figures

[0032] Fig. 1 shows a flow chart describing a method for forming a metallic coating from a metallization liquid.

[0033] Fig. 2 shows an aspect of obtaining a metallic coating.

[0034] Fig. 3 shows a further flow chart describing the method for forming the metallic coating from the metallization liquid.

[0035] Fig. 4 shows a further aspect for obtaining the metallic coating.

[0036] Fig.5 shows an image of platinum (Pt) on an electrolyzer.

[0037] Fig. 6 shows an image of islands of Pt on an electrolyzer.

[0038] Fig. 7 shows an image of the obtained metallic coating 20 made of gold (Au) and palladium (Pd) on a substrate of silicone.Detailed description of the invention

[0039] The invention will now be described on the basis of the drawings. It will be understood that the embodiments and aspects of the invention described herein are only examples and do not limit the protective scope of the claims in any way. The invention is defined by the claims and their equivalents. It will be understood that features of one aspect or embodiment of the invention can be combined with the feature of a different aspect or aspects and / or embodiments of the invention.

[0040] In a first aspect, a metallization liquid 10 is taught in this document. The metallization liquid 10 comprises at least one metal ionic precursor, at least one structuring liquid, and at least one propelling liquid. The at least one metal ionic precursor comprises at least one metal cation and at least one counterion. The at least one structuring liquid is for dissolving the at least one metal ionic precursor in the metallization liquid 10. The at least one propelling liquid is for nebulizing the metallization liquid 10.

[0041] In one aspect, the metal cation is a positively charged ion. The counterion is, in one aspect, an ion having a charge equal to the charge of the cation, but of a different sign, in other words an anion. In another aspect, the at least one counterion is a ligand. In a further aspect, the counterion is an organic ligand.

[0042] In one aspect, the metal cation is stabilized by the ligand, thereby forming an organometallic complex, such as a salt. The salt comprises coordinate bonds. In one further aspect, the metal cation is stabilized by the anion, thereby forming a salt with ionic bonds.

[0043] In one aspect, the metal cation is selected from any one of Au, Ag, Pt, Pd, Cu, Ni, Co, Zn, In, Ti, V, Mn, Fe, Cr, Zr, Nb, Mo, W, Ru, Rh, Ca, Re, Os, Ir, Al, Ga, Sn, and Sb. In one further aspect, the metal cation is selected from any one of Au, Ag, Pt, Pd, Cu, Ti, Nb, Ni, Co, Ru, Ir, and Rh.

[0044] In one further aspect, the counterion is selected from the group of consisting of any one of M(N03)n, M(SO4)n, MCln, HmMCln+m, and MN, where “M” is a metal atom, or metal alloy, with a valence of “n”, H is hydrogen, NO3 is nitrate, SO4 is sulfate, Cl is chloride, “N” is alkyl-, alyl-, aceto-, carbonyl, carboxyl, cyclopentadienyl, phenyl-, biphenyl-, pyridine-, bipyridine-, aromatic, cyano-, amide and other organic moieties, and “m” is a valence of the counterion. In one further aspect, the at least one counterion is selected from the group consisting of any of M(N03)n, HmMCln+m, and MN, where "M" is a metal atom, with a valence of "n", H is hydrogen, NO3 is nitrate, "N" comprises an oxalate, hydroxide, ketone, carboxyl, lactone, and "m" is a valence of the counterion. In one further aspect, the metal cation is selected from Pt and the at least one counterion is PUPtCk, as a salt..

[0045] In one aspect, the at least one structuring liquid is a solvent.

[0046] In one further aspect, the solubility of the metal ionic precursor in the solvent is at least 15 mg / ml in room temperature, i.e., 25°C. In one further aspect, the solubility of the metal ionic precursor in the solvent is at least 50 mg / ml in room temperature. In one further aspect, the solubility of the metal ionic precursor in the solvents is at least 100 mg / ml at room temperature.

[0047] In one further aspect, the metal ionic precursor is at a concentration of at most 25 wt.% with respect to the metallization liquid 10. In one further aspect, the metal ionic precursor is at a concentration between 1 and 15 wt.% with respect to the metallization liquid 10. In one further aspect, the metal ionic precursor is at a concentration between 5 and 10 wt.% with respect to the metallization liquid 10.

[0048] The structuring liquid may be selected from one of glycols, glycol ethers, glycol esters, carbonate esters, water, ketones, sulfoxides and their derivatives, or a combination thereof.

[0049] In one aspect, the propelling liquid is selected from one of solvents having dynamic viscosity at 25°C of between 0.5 mPa.s and 5 mPa.s.

[0050] In one further aspect, the propelling liquid is selected from one of alcohol, cyclic alcohols, toluene, dioxane, ethylamines, glycol ethers, acetonitrile and their derivatives, or a combination thereof.

[0051] In one further aspect, the structuring liquid is at a concentration of between 3 wt.% and 40 wt.% with respect to the metallization liquid 10, and / or the propelling liquid is at a concentration of between 60 wt.% and 97 wt.% with respect to the metallization liquid 10.

[0052] In one further aspect, the metallization liquid 10 comprises at least one additive selected from one of: organic molecules, polymers, conductive polymers, carbon nanotubes (CNT), densifiers, and surfactants.

[0053] Fig. 1 shows a flow chart of a method for forming a metallic coating 20 from the metallization liquid 10 on a substrate 30.

[0054] In one aspect, the substrate 30 is selected from one of a two-dimensional (2D) or a three-dimensional (3D) substrate. In a further aspect, the substrate 30 is selected from one of a polyimide (PI), a woven textile, a polyethylene terephthalate (PET), a filter type substrate, a plastic substrate, a metal felt substrate, an aluminum substrate, a ceramic substrate, a glass substrate, and a metal mesh substrate. In one aspect, the aluminium substrate is an aluminium foil. In one further aspect, the metal mesh substrate is a titanium mesh substrate.

[0055] The method according to Fig. 1 comprises applying in an application step S100 the metallization liquid 10 on the substrate 30, such that the metallization liquid 10 has a thickness on the substrate 30, and the thickness of the metallization liquid 10 on the substrate 30 is at most 2 mm. The method further comprises in an exposure step S200 exposing the metallization liquid 10 to a plasma 50 at atmospheric conditions, thereby obtaining in an obtention step S400 the metallic coating 20.

[0056] A thickness of the metallization liquid 10 higher than 2 mm has detrimental effect. The plasma 50 does not penetrate the metallization liquid 10. The metallization of the metallic coating 20 is uneven.

[0057] The applying SI 00 comprises drop-casting, spray-coating, immersion, inkjet printing, aerosol spraying, aerosol jet printing, spin-coating, or screen printing. The applying S100 is, one further aspect, a depositing of the metallization liquid 10 on the substrate 30.

[0058] The applying SI 00 can be applied using application equipments, for example, a nozzle, an inkjet printer, or an aerosol jet printer.

[0059] In one aspect, the thickness of the metallization liquid 10 on the substrate 30 is below 2 mm, and for example below 0.5 mm.

[0060] In one aspect, the exposure step S200 is conducted with a device disclosed in the international patent application WO 2015071746 Al, but this is not limiting of the invention.

[0061] The exposure step S200 is conducted, in one aspect, at a gas flow rate, i.e., an exposing gas flow rate, of at least 0.5 liters / minute, and / or for an exposure time of at most 3600 seconds, and / or at a power of at most 3000 Watts (W), and / or at a plasma radiofrequency (RF) between 50 Hz and 5 GHz.

[0062] The exposure step S200 is conducted, in a further aspect, at a gas flow rate of at least 1 liter / minute, and / or for an exposure time between 1 and 120 seconds, and / or at a power of between 5 W and 100 W, and / or at a plasma radiofrequency (RF) between 1 kHz and 1 GHz. In an aspect, the gas flow rate is 3-15 liters / minute, and / or for an exposure time between 1 and 30 seconds, and / or at a power of between 5 W and 40 W, and / or at a plasma radiofrequency (RF) between 1 kHz and 100 MHz GHz. In a further aspect, the exposure time is sufficiently short to form a substantially single spot. In other words, the term “a single spot” means that the nozzle is not moving, and so the metallization liquid 10 is deposited in a single spot on the substrate 30. The term “the exposure time is sufficiently short” means that the exposure time may be below 1 second and may result in a metallization of the metallization liquid on the substrate.

[0063] The values of the gas flow rate, the exposure time, the power, and the plasma are dependent on the type of the substrate 30, the composition of the metallization liquid 10, and the equipments to conduct the applying S100 of the metallization liquid 10.

[0064] In one aspect, the plasma 50 is a plasma comprising partially ionized gas. The partially ionized gas is not in thermodynamic equilibrium. A radio frequency (RF) plasma is a partially ionized gas not in thermodynamic equilibrium. The partially ionized gas may exist at relatively low temperatures, for example, below 120 °C.

[0065] The plasma 50 is, in one aspect, selected from one of argon (Ar), nitrogen, oxygen, hydrogen, air, helium, neon, xenon, ammonia, ethane (C2H6), carbon dioxide, carbon monoxide, methane (CH4), propane (CsHs), silane (SiH4), nitrogen dioxide, nitrogen monoxide, or a combination thereof.

[0066] The at least one metal ionic precursor reacts with the plasma 50 at atmospheric condition during the exposure step S200 of exposing the metallization liquid 10 to the plasma50, resulting in the electrochemical reduction of the at least one metal ionic precursor. A majority, i.e., at least 95 % of the structuring liquid and the propelling liquid evaporates during the electrochemical reduction. The metal ions of the metal ionic precursor receive electrons from the plasma 50 and are converted into metal atoms. The processes of receiving and conversion occur simultaneously. The metal atoms assemble to form the metallic coating 20 that adheres to the substrate 30, such as in physical vapor deposition (PVD).

[0067] The metallic coating 20 formed thereby is, in one aspect, a polycrystalline metal layer, i.e., film.

[0068] In one aspect, the metallic coating 20 has a thickness comprised between 2 nm and 500 nm. In one further example, the metallic coating 20 has a thickness comprised between 2 nm and 100 nm.

[0069] In one aspect, the poly crystalline metal film adheres to at least part of a surface 35 of the substrate 30. In one further aspect, the polycrystalline metal layer is a partial layer. In other words, the partial layer is a layer comprising metal nano islands and / or particles, for example, to maximize metal surface area or other parameters. In one further aspect, the metallic coating 20 is not completely formed and / or does not adhere the surface 35 of the substrate 30. In one further aspect, the metallic coating 20 coats only part of the surface 35 of the substrate 30.

[0070] In one further aspect, the polycrystalline metal layer is a layer of separate particles, i.e., single particles.

[0071] In one further aspect, the metallic coating 20 comprises metal oxides. The metal oxides are selected from any one of silver oxide, copper oxide, nickel oxide, zinc oxide, indium oxide, titanium oxide (TiCh), iron oxide, zirconium oxide, niobium oxide, niobium pentoxide (bt^Os), osmium oxide, iridium oxide ruthenium oxide, rhodium oxide, aluminum oxide, tin oxide, and antinomy oxide. In one aspect, the metal oxides are selected from TiCh and Nb2Os, such that the metallic coating 20 has specific dielectric parameters.

[0072] In one aspect, the thickness, the uniformity and the topology of the metallic coating 20 are dependent on the composition of the metallization liquid 10. In one further aspect, the thickness, the uniformity and the topology of metallic coating 20, i.e., the polycrystalline metal film, can be controlled by the value of the gas flow rate, and / or the exposure time, and / or the power, and / or the plasma RF. The thickness, the uniformity andthe topology of the polycrystalline metal film can be controlled by the gas flow rate to propel the metallization liquid 10 through the plasma 50 at atmospheric conditions.

[0073] In one further aspect, the metallic coating 20 has a print resistivity of at least 1 ohm / sq, and / or a dielectric constant at 25°C of at least 20. In one further aspect, the metallic coating 20 has a print resistivity of at least 4 ohm / sq, and / or a dielectric constant at 25°C of at least 35. In one further aspect, the metallic coating 20 has a print resistivity of at least 5 ohm / sq.

[0074] In one aspect, the metallic coating 20 is used in an antibacterial application, electronic application, catalytic application, or energy application. The metallic coating 20 is used, in one aspect, as a biological sensor, as a part of a bioelectronic sensor, in preparation of electrolyzers, in preparation of energy storage devices, such as fuel cells, as part of a porous transport membrane, as a seed layer for future electroless or electroplating, or as a part of a solar panel device.

[0075] Fig. 2 illustrates in one view the obtention step S400 of obtaining the metallic coating 20. Fig. 2 shows the exposure step S200 of exposing the metallization liquid 10 to the plasma 50 at atmospheric conditions.

[0076] Fig. 3 shows a further flow chart of a method for forming the metallic coating 20.

[0077] The method further comprises in a nebulization step S50 nebulizing the metallization liquid 10. The method further comprises in an exposure step S200 exposing the metallization liquid 10 to the plasma 50 at atmospheric conditions, so that a nebulized metal 15 is formed. The nebulized metal 15 refers to a metal in an aerosol and / or vapor form. The method comprises in an application step S100 applying the nebulized metal 15 on the substrate 30, thereby obtaining in an obtention step S400 the metallic coating 20.

[0078] The nebulizing 50 is selected, in one aspect, from one of aerosolizing, and / or vaporizing.

[0079] In one aspect, the nebulizing S50 is conducted at a nebulization gas flow rate of at least 0.01 liters / minute, and / or the exposing S200 is conducted for an exposure time of at most 3600 seconds, and / or at a power of at most 3000 Watts (W); and / or at a plasma radiofrequency (RF) between 50 Hz and 5 GHz. In one further aspect, the nebulizing S50 is conducted at a nebulization gas flow rate of at least 0.1 liters / minute, and / or the exposing S200 is conducted for an exposure time between 1 and 120 seconds, and / or at a power of between 5 W and 100 W, and / or at a plasma radiofrequency (RF) between 1 kHz and 1 GHz.

[0080] Fig. 4 illustrates in a further view the obtention step S400 of obtaining the metallic coating 20. Fig. 4 shows an aerosol and / or a vapor 45 generated by the nebulizing generator 40 from the metallization liquid 10. The aerosol and / or the vapor 45 is further exposed S200 to the plasma 50, so that the nebulized metal 15 is formed and subsequently applied SI 00 on the substrate 30. thereby obtaining S400 the metallic coating 20.

[0081] In one further aspect, the method is adapted to a roll-to-roll production. The metallization liquid 10 is deposited, i.e., applied, in the application step S100, via a high- precision deposition method onto the substrate 30 on the roll-to-roll production line. In a further aspect, the high-precision deposition method is inkjet printing.Examples

[0082] The following are a few non-limiting examples for deposition of metallic coating 20, i.e., polycrystalline metal thin films, using different methods and having different properties.

[0083] Example I. A metallization liquid 10 comprises a metal ionic precursor made of silver nitrate (AgNCE) at a concentration of 17 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises a mixture of ethylene glycol and propylene glycol (1.2: 1 ratio) as a structuring liquid and a mixture of propylene glycol methyl ether and propylene glycol methyl ether acetate (1.5: 1 ratio) as a propelling liquid. The metallization liquid 10 is deposited, i.e., applied in an application step S100 onto a two-dimensional (2D) substrate 30 made of polyimide (PI). The substrate 30 made of PI is then exposed in an exposure step S200 to, i.e., run under, a plasma 50 of pure Argon (Ar) gas at atmospheric conditions by using an atmospheric plasma nozzle, as shown in Fig. 2. The exposing S200 is conducted at a plasma radiofrequency (RF frequency) of 13.56 MHz, at a power of 50 Watts (W), at a gas flow rate of 5 liters / minute, and for an exposure time of 10 seconds. The obtained metallic coating 20 is a connected conductive polycrystalline silver layer. The print resistivity of the metallic coating 20 is 1 ohm / sq.

[0084] Example II. A metallization liquid 10 comprises a metal ionic precursor made of AgNCE at a concentration of 3 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises ethylene glycol monopropyl ether as a structuring liquid and a mixture of ethanol and propylene glycol methyl ether acetate (1 : 1.2 ratio) as apropelling liquid. The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is aerosolized (nebulized) S50 at an aerosol (nebulizing) flow rate of 0.2 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a plasma 50 of pure Ar gas at atmospheric conditions, as shown in Fig. 4. The exposing S200 is conducted at a plasma RF frequency of 12 MHz, at a power of 20 W, at a gas flow rate of 10 liters / minute, and for an exposure time of 4 seconds. The metallization liquid 10 is then applied S100 onto a substrate 30 made of woven textile substrate. The obtained metallic coating 20 is a woven textile coated with a spread of silver nanoparticles. The obtained metallic coating 20 shows an antibacterial effect.

[0085] Example III. A metallization liquid 10 comprises a metal ionic precursor made of AgNCh at a concentration of 14 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises ethylene glycol monopropyl ether as a structuring liquid and a mixture of propylene glycol methyl ether and n-propanol (1.5: 1 ratio) as a propelling liquid. The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is nebulized S50 at an aerosol (nebulizing) flow rate of 0.3 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a plasma 50 of pure Ar gas at atmospheric conditions, as shown in Fig. 4. The metallization liquid 10 is deposited onto a substrate 30 made of a 2D polyethylene terephthalate (PET). The exposing S200 is conducted at a plasma RF frequency of 12 MHz, at a power of 25 W, at a gas flow rate of 8 liters / minute, and for an exposure time of 3 seconds. The obtained metallic coating 20 is a connected conductive polycrystalline silver layer. The print resistivity of the obtained metallic coating 20 is 5 ohm / sq.

[0086] Example IV. A metallization liquid 10 comprises a metal ionic precursor made of hydrogen(tetrachloridoaurate) (HfAuCU]) at a concentration of 12 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises a mixture of ethylene glycol and propylene glycol (1 : 1.1 ratio) as a structuring liquid and a mixture of propylene glycol methyl ether and propylene glycol methyl ether acetate (2: 1 ratio) as a propelling liquid. The metallization liquid 10 is deposited, i.e., applied in an application step S100 onto a 2D substrate 30 made of PI. The substrate 30 made of PI is then run under, i.e., exposed S200 to a plasma 50 of pure Ar gas at atmospheric conditions by using an atmospheric plasmanozzle, as shown in Fig. 2. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, at a power of 30 W, at a gas flow rate of 7 liters / minute, and for an exposure time of 15 seconds. The obtained metallic coating 20 is a connected conductive polycrystalline gold layer. The print resistivity of obtained the metallic coating 20 is 4 ohm / sq.

[0087] Example V. A metallization liquid 10 comprises a metal ionic precursor made of HfAuCh] at a concentration of 2.5 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises a mixture of ethylene glycol monopropyl ether and water (3 : 1 ratio) as a structuring liquid and a mixture of ethanol and propylene glycol methyl ether acetate (1 : 1.3 ratio) as a propelling liquid. The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is aerosolized (nebulized) S50 at an aerosol (nebulizing) flow rate of 0.22 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a plasma 50 of pure Ar gas at atmospheric conditions, as shown in Fig. 4. The metallization liquid 10 is deposited onto a substrate 30 made of a two-dimensional (2D) filter type. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, a power of 22 W, at a gas flow rate of 7 liters / minute, and for an exposure time of 5 seconds. The obtained metallic coating 20 is a filter substrate coated with a spread of gold nanoparticles. The obtained metallic coating 20 shows a catalytic effect and can be used as a simple biological sensor.

[0088] Example VI. A metallization liquid 10 comprises a metal ionic precursor made of dihexachloroplatinic (IV) acid (H2[PtCle]) at a concentration of 1.0 wt. % respect to the metallization liquid 10. The metallization liquid 10 comprises ethylene glycol as a structuring liquid and a mixture of propylene glycol methyl ether and propylene glycol methyl ether acetate (1.2: 1 ratio) as a propelling liquid. The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is aerosolized (nebulized) S50 at an aerosol (nebulizing) flow rate of 0.3 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a plasma 50 of pure Ar gas at atmospheric conditions, as shown in Fig. 4. The metallization liquid 10 is deposited onto a substrate 30 made of plastic. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, a power of 25 W, at a gas flow rate of 8 liters / minute, and for an exposure time of 10 seconds of exposure. The obtained metallic coating 20 is a plastic substrate coated with a spread of platinum nanoparticles. The obtainedmetallic coating 20 shows a strong catalytic effect, for example in decomposing hydrogen peroxide (H2O2).

[0089] Example VII. A metallization liquid 10 comprises a metal ionic precursor made of EEfPtCle] at a concentration of 23 wt. % of the metallization liquid 10. The metallization liquid 10 comprises a mixture of ethylene glycol and propylene glycol (1 : 1.3 ratio) as a structuring liquid and a mixture of propylene glycol methyl ether and propylene glycol methyl ether acetate (1.2: 1 ratio) as a propelling liquid. The metallization liquid 10 is deposited, i.e., applied in an application step S100 onto a 2D substrate 30 made of PI. The substrate 30 made of PI is then exposed in an exposure step S200 to, i.e., run under, a plasma 50 of pure Ar gas at atmospheric conditions by using an atmospheric plasma nozzle, as shown in Fig. 2. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, at a power of 45 W of power, at a gas flow rate of 7 liters / minute, and for an exposure time of 5 seconds of exposure. The obtained metallic coating 20 is a connected conductive polycrystalline platinum layer. The print resistivity of the metallic coating 20 is 5 ohm / sq. The obtained metallic coating 20 can be used as a part of a bioelectronic sensor.

[0090] Example VIII. A metallization liquid 10 comprises a metal ionic precursor made of H2[PtCle] at a concentration of 27 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises a mixture of ethylene glycol monopropyl ether and water (2: 1 ratio) as a structuring liquid and a mixture of propylene glycol methyl ether and n- propanol (1 : 1.3 ratio) as a propelling liquid. The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is aerosolized (nebulized) S50 at an aerosol (nebulizing) flow rate of 0.25 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a plasma 50 of pure Ar gas at atmospheric conditions, as shown in Fig. 4. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, at a power of 22 W of power, at a gas flow rate of 10 liters / minute gas flow rate, and for an exposure time of 5 seconds. The metallization liquid 10 is then applied S100 onto a substrate 30 made of a metal felt. The obtained metallic coating 20 is a metal felt substrate coated with a full uninterrupted layer of platinum, with each metal fiber coated individually. The obtained metallic coating 20 can withstand harsh chemical conditions and can be used in preparation of electrolyzers or fuel cells, as part of a porous transport membrane.

[0091] Fig. 5 shows an image of the obtained metallic coating 20 of Example VIII. Fig. 5 shows the obtained metallic coating 20 made of the layer of platinum in an electrolyzer. The image of Fig. 5 was obtained with a Zeiss Gemini scanning electron microscope at a magnification of 3,500 under the condition of 5 kV and an InLens detector.

[0092] Example IX. A metallization liquid 10 comprises a metal ionic precursor made of EEfPtCle] at a concentration of 12 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises a mixture of ethylene glycol and water (1 : 1 ratio) as a structuring liquid and a mixture of propylene glycol methyl ether acetate and n-propanol (1 : 1.5 ratio) as a propelling liquid. The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is aerosolized (nebulized) S50 at an aerosol (nebulizing) flow rate of 0.22 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a plasma 50 of pure Ar gas at atmospheric conditions, as shown in Fig. 4. The exposing S200 is conducted at a plasma RF frequency of 12 MHz, at a power of 25 W of power, at a gas flow rate of 8 liters / minute, and for an exposure time of 7 seconds. The metallization liquid 10 is then applied S100 onto a substrate 30 made of a metal mesh. The obtained metallic coating 20 is a metal mesh substrate coated with a platinum (Pt) drops / nanoislands. The obtained metallic coating 20 has a catalytic effect and can be used in preparation of energy storage devices.

[0093] Fig. 6 shows an image of the obtained metallic coating 20 of Example IX. Fig. 6 shows the obtained metallic coating 20 made of Pt drops / nanoislands in an electrolyzer. The image of Fig. 6 was obtained with a Zeiss Gemini scanning electron microscope at a magnification of 4,000 under the condition of 5 kV and an InLens detector.

[0094] Example X. A metallization liquid 10 comprises a metal ionic precursor made of palladium(II) nitrate (Pd(NOs)2 at concentration of 8 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises propylene carbonate and y-butyrolactone (20: 1 ratio) as a structuring liquid and 1,4-dioxane as a propelling liquid. The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is aerosolized (nebulized) S50 at an aerosol (nebulizing) flow rate of 0.22 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a plasma 50 of pure Ar gas at atmospheric conditions, as shown in Fig. 4. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, at apower of 20 W, at a gas flow rate of 8 liters / minute, and for an exposure time of 3 seconds of exposure. The metallization liquid 10 is then applied S100 onto a substrate 30 made of plastic. The obtained metallic coating 20 is a plastic substrate coated with a full uninterrupted layer of palladium. The obtained metallic coating 20 can be used as a seed layer for future electroless or electroplating.

[0095] Example XI. A metallization liquid 10 comprises a metal ionic precursor made of copper(II) nitrate (CufNCh ) at a concentration of 23 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises propylene glycol as a structuring liquid and n-propanol as a propelling liquid. The metallization liquid 10 is printed, i.e., applied in an application step S100 onto a 2D substrate 30 made of PET. The substrate 30 made of PET is then exposed in an exposure step S200 to, i.e., run under, a plasma 50 comprising 98% of Ar and 2% of dihydrogen (EE) gas at atmospheric conditions by using an atmospheric plasma nozzle, as shown in Fig. 2. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, at a power of 35 W, at a gas flow rate of 5 liters / minute, and for an exposure time of 2 seconds. The obtained metallic coating 20 is a connected conductive polycrystalline copper layer. The print resistivity of the metallic coating 20 is 1 ohm / sq. The metallic coating 20 can be used as a part of a solar panel device.

[0096] Example XII. A metallization liquid 10 comprises a metal ionic precursor made of CU(NOS)2 at a concentration of 17 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises ethylene glycol as a structuring liquid and a mixture of n- propanol and toluene (3: 1 ratio) as a propelling liquid. . The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is aerosolized (nebulized) S50 at an aerosol (nebulizing) flow rate of 0.25 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a 98% Ar and 2% H2 plasma 50 at atmospheric conditions, as shown in Fig. 4. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, at a power of 22 Watts (W), at a gas flow rate of 10 liters / minute, and for an exposure time of 2 seconds. The metallization liquid 10 is then applied S100 onto a substrate 30 made of plastic. The obtained metallic coating 20 is a plastic substrate coated with a full uninterrupted layer of copper. The print resistivity of the metallic coating 20 is 2 ohm / sq. The metallic coating 20 can be used as a part of a solar panel device.

[0097] Example XIII. A metallization liquid 10 comprises a metal ionic precursor made of a mixture of HfAuCU] and PdfNCh at a concentration of 9 wt. % and 12 wt. %, with respect to the metallization liquid 10. The metallization liquid 10 comprises a mixture of ethylene glycol, propylene carbonate and y-butyrolactone (6:18: 1 ratio) as a structuring liquid and 1,4-dioxane as a propelling liquid. The metallization liquid 10 is deposited, i.e., applied in an application step S100 onto a two-dimensional (2D) substrate 30 made of silicone. The substrate 30 made of silicone is then exposed in an exposure step S200 to, i.e., run under, a plasma 50 of pure Ar gas at atmospheric conditions by using an atmospheric plasma nozzle, as shown in Fig. 2. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, at a power of 40 W, at a gas flow rate of 4 liters / minute, and for an exposure time of 10 seconds. The obtained metallic coating 20 is a connected conductive polycrystalline gold and palladium layer.

[0098] Fig. 7 shows an image of the obtained metallic coating 20 of Example XIII. Fig. 7 shows the obtained metallic coating 20 made of the gold and palladium layer on the substrate 30 made of silicone. The image of Fig. 7 was obtained with a Zeiss Gemini scanning electron microscope at a magnification of 620,000 under the condition of 5 kV and an InLens detector. The inset graph on the right side of Fig. 5 is an energy-dispersive spectroscopy (EDS) spectrum of the same place on the sample of the obtained metallic coating 20 generated with the same instrument as the image at a magnification of 12,000 under the condition of 10 kV and a SE2 detector, showing peaks for Au, Pd and the substrate 30 made of silicon.

[0099] Example XIV. A metallization liquid 10 comprises a metal ionic precursor made of a mixture of Pd(NOs)2 and AgNCE at a concentration of 1.3 wt. % and 13 wt. %, respectively, with respect to the metallization liquid 10. The metallization liquid 10 comprises a mixture of ethylene glycol monopropyl ether, propylene carbonate and y-butyrolactone (15:23: 1 ratio) as a structuring liquid and a mixture of 1,4-dioxane and n-propanol (1.5: 1 ratio) as a propelling liquid. The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is aerosolized (nebulized) S50 at an aerosol (nebulizing) flow rate of 0.2 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a plasma 50 of pure Ar gas at atmospheric conditions, as shown in Fig. 4. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, at a power of 25 W, at a gas flow rate of 8 liters / minute,and for an exposure time of 4 seconds. The metallization liquid 10 is then applied SI 00 onto a substrate 30 made of plastic. The obtained metallic coating 20 is a plastic substrate coated with a full uninterrupted layer of silver and palladium.

[0100] Example XV. A metallization liquid 10 comprises a metal ionic precursor titanium made of bis-(ammonium lactato) dihydroxide at a concentration of 13 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises a mixture of ethylene glycol and water (1:3 ratio) as a structuring liquid and n-propanol as a propelling liquid. The metallization liquid 10 is deposited, i.e., applied in an application step S100 onto a 2D substrate 30 made of aluminium (Al). The substrate 30 made of Al is then exposed in an exposure step S200 to, i.e., run under, a plasma 50 of pure Ar gas at atmospheric conditions by using an atmospheric plasma nozzle, as shown in Fig. 2. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, at a power of 40 W, at a gas flow rate of 8 liters / minute, plasma 50 of pure oxygen gas, and for an exposure time of 15 seconds. The obtained metallic coating 20 is a titanium oxide layer with a high dielectric constant.

[0101] Example XVI. A metallization liquid 10 comprises a metal ionic precursor niobium oxalate at a concentration of 9 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises a mixture of propylene glycol, oxalic acid and water (1 :2:6 ratio) as a structuring liquid and n-propanol as a propelling liquid. The metallization liquid 10 is deposited, i.e., applied in an application step S100 onto a 2D substrate 30 made of Al. The substrate 30 made of Al is then exposed in an exposure step S200 to, i.e., run under, a plasma 50 of pure oxygen gas at atmospheric conditions by using an atmospheric plasma nozzle, as shown in Fig. 2. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, at a power of 45 W, at a gas flow rate of 10 liters / minute, and for an exposure time of 10 seconds. The obtained metallic coating 20 is a niobium oxide layer with a high dielectric constant.

[0102] Example XVII. A metallization liquid 10 comprises a metal ionic precursor made of niobium oxalate at a concentration of 14 wt. % with respect to the metallization liquid 10. The metallization liquid 10 comprises a mixture of ethylene glycol, oxalic acid and water (1 :3:8 ratio) as a structuring liquid and n-propanol as a propelling liquid. The metallization liquid 10 is deposited, i.e., applied in an application step S100 onto a 2D substrate 30 made of Al. The substrate 30 made of Al is then exposed in an exposure step S200 to, i.e., run under, a plasma 50 comprising 95% of Ar and 5% of H2 gas at atmospheric conditions byusing an atmospheric plasma nozzle, as shown in Fig. 2. The exposing S200 is conducted at a plasma RF frequency of 13.56 MHz, at a power of 45 W, at a gas flow rate of 10 liters / minute, and for an exposure time of 12 seconds. The obtained metallic coating 20 is a niobium layer with a high dielectric constant.

[0103] Example XVIII. A metallization liquid 10 comprises a metal ionic precursor made of H2[IrCle] at a concentration of 2 wt. % with respect to the metallization liquid 10. In addition, the metallization liquid 10 comprises a mixture of ethylene glycol and water (1:2 ratio) as a structuring liquid and n-propanol as a propelling liquid. The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is aerosolized (nebulized) S50 at an aerosol (nebulizing) flow rate of 0.18 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a plasma 50 of 95% Ar and 5% H2 gas at atmospheric conditions, as shown in Fig. 4. The exposing S200 is conducted at a plasma RF frequency of 15 MHz, at a power of 30 W of power, at a gas flow rate of 10 liters / minute, and for an exposure time of 4 seconds. The metallization liquid 10 is then applied S100 onto a substrate 30 made of a titanium mesh. The obtained metallic coating 20 has a catalytic effect and can be used in preparation of energy storage devices.

[0104] Example XIX. A metallization liquid 10 comprises a metal ionic precursor made of Rh(NO3)3 with at a concentration of 4 wt. % with respect to the metallization liquid 10. In addition, the metallization liquid 10 comprises a mixture of ethylene glycol and water (1: 1 ratio) as a structuring liquid and mixture of propylene glycol methyl ether and propylene glycol methyl ether acetate (1.5:1 ratio) as a propelling liquid. The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is aerosolized (nebulized) S50 at an aerosol (nebulizing) flow rate of 0.2 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a plasma 50 of 95% Ar and 5% H2 gas at atmospheric conditions, as shown in Fig. 4. The exposing S200 is conducted at a plasma RF frequency of 20 MHz, at a power of 28 W of power, at a gas flow rate of 8 liters / minute, and for an exposure time of 3 seconds. The metallization liquid 10 is then applied S100 onto a substrate 30 made of a titanium mesh. The obtained metallic coating 20 has a catalytic effect and can be used in preparation of energy storage devices.

[0105] Example XX. A metallization liquid 10 comprises a metal ionic precursor made of a mixture of EfPtCle] and EflrCle] with at a concentration of 17 wt. % and 2 wt. % with respect to of the metallization liquid 10. In addition, the metallization liquid 10 comprises a mixture of ethylene glycol and water (1: 1 ratio) as a structuring liquid and mixture of propylene glycol methyl ether and n-propanol (1 : 1.6 ratio) as a propelling liquid. The metallization liquid 10 is then aerosolized (nebulized) in a nebulization step S50 using an aerosol (nebulizing) generator 40. The metallization liquid 10 is aerosolized (nebulized) S50 at an aerosol (nebulizing) flow rate of 0.22 liters / minute. The metallization liquid 10 is exposed in the exposure step S200 to a plasma 50 of 95% Ar and 5% EE gas at atmospheric conditions, as shown in Fig. 4. The exposing S200 is conducted at a plasma RF frequency of 18 MHz, at a power of 28 W of power, at a gas flow rate of 9 liters / minute, and for an exposure time of 6 seconds. The metallization liquid 10 is then applied S100 onto a substrate 30 made of a titanium mesh. The obtained metallic coating 20 has a catalytic effect and can be used in preparation of energy storage devices.Reference numerals10 metallization liquid15 nebulized metal20 metallic coating30 substrate35 surface40 nebulizing generator45 aerosol and / or vapor50 plasma100 apparatus

Claims

Claims1. A method for forming a metallic coating (20) from a metallization liquid (10), the metallization liquid (10) comprising at least one metal ionic precursor, at least one structuring liquid, at least one propelling liquid, wherein the at least one metal ionic precursor comprises at least one metal cation and at least one counterion, the at least one structuring liquid for dissolving the at least one metal ionic precursor in the metallization liquid (10), the at least one propelling liquid for nebulizing the metallization liquid (10); and wherein the method comprises: nebulizing (S50) the metallization liquid (10); applying (S100) the metallization liquid (10) on a substrate (30), and exposing (S200) the metallization liquid (10) to a plasma (50) at atmospheric conditions, thereby obtaining (S400) the metallic coating (20).

2. The method of claim 1, wherein the metallization liquid (10) has a thickness on a substrate (30), and the applying (S100) of the metallization liquid (10) on the substrate (30) is conducted such that the thickness of the metallization liquid (10) is at most 2 mm.

3. The method of claim 1 or 2, wherein the exposing (S200) is conducted at a gas flow rate of at least 0.5 liters / minute; and / or for an exposure time of at most 3600 seconds; and / or at a power of at most 3000 Watts (W); and / or at a plasma radiofrequency (RF) between 50 Hz and 5 GHz.

4. The method of any one of the above claims, wherein the metallization liquid (10) is exposed (S200) to the plasma (50) selected from one of argon (Ar), nitrogen, oxygen, hydrogen, air, helium, neon, xenon, ammonia, ethane (C2H6), carbon dioxide, carbon monoxide, methane (CH4), propane (CsHs), silane (SiH4), nitrogen dioxide, nitrogen monoxide, or a combination thereof.

5. The method of any one of the above claims, wherein the nebulizing (S50) of the metallization liquid (10) is carried out prior to the applying (S100).

6. The method of any one of the above claims, wherein the method comprises the steps in the following order: nebulizing (S50) the metallization liquid (10); exposing (S200) the metallization liquid (10) to the plasma (50) at atmospheric conditions, thereby obtaining (S250) a nebulized metal (15); and applying (S100) the nebulized metal (15) on the substrate (30), thereby obtaining (S400) the metallic coating (20).

7. The method of claims 5 or 6, wherein the nebulizing (S50) is selected from one of aerosolizing and / or vaporizing.

8. The method of any one of claims 5 to 7, wherein the nebulizing (S50) is conducted at a nebulization gas flow rate of at least 0.01 liters / minute; and / or the exposing (S200) is conducted at a plasma gas flow rate of at least 0.5 liters / minute; and / or for an exposure time of at most 3600 seconds; and / or at a power of at most 3000 Watts (W); and / or at a plasma radiofrequency (RF) between 50 Hz and 5 GHz.

9. The method of any one of claims 5 to 8, wherein the nebulizing (S50) is conducted at a nebulization gas flow rate of at least 0.1 liters / minute; and / or the exposing (S200) is conducted at a plasma gas flow rate of at least 2 liters / minute; and / or for an exposure time between 1 and 120 seconds; and / or at a power of between 5 W and 100 W; and / or at a plasma radiofrequency (RF) between 1 kHz and 1 GHz.

10. The method of any of the above claims, wherein the at least one metal cation is selected from any one of Au, Ag, Pt, Pd, Cu, Ti, Nb, Ni, Co, Ru, Ir, and Rh; and the at least one counterion is selected from the group consisting of any of M(N03)n, HmMCln+m, and MN, where "M" is a metal atom, with a valence of "n", H is hydrogen, NO3 is nitrate, "N" comprises an oxalate, hydroxide, ketone, carboxyl, lactone, and "m" is a valence of the counterion.

11. The method of any one of the above claims, wherein the at least one metal ionic precursor is at a concentration of at most 25 wt.% with respect toto the at least one structuring liquid and the at least one propelling liquid, preferably between 1 and 15 wt.% with respect to the at least one structuring liquid and the at least one propelling liquid, more preferably between 5 and 10 wt.% with respect to the at least one structuring liquid and the at least one propelling liquid.

12. The method of any one of the above claims, wherein the at least one structuring liquid is a solvent, and the solubility of the at least one metal ionic precursor in the solvent is at least 15 mg / ml at 25°C, preferably of at least 50 mg / ml at 25°C, more preferably of at least 100 mg / ml at 25°C.

13. The method of any one of the above claims, wherein the at least one structuring liquid is selected from one of glycols, glycol ethers, glycol esters, carbonate esters, water, ketones, sulfoxides and their derivatives, or a combination thereof.

14. The method any one of the above claims, wherein the at least one propelling liquid is a solvent having dynamic viscosity at 25°C of between 0.5 mPa.s and 5 mPa.s.

15. The method of any one of the above claims, whereinthe at least one propelling liquid is selected from one of alcohol, cyclic alcohols, toluene, dioxane, ethylamines, glycol ethers, acetonitrile and their derivatives, or a combination thereof.

16. The method of any one of the above claims, wherein- the structuring liquid is at a concentration comprised between 3 wt.% and 40 wt.% with respect to the metallization liquid (10); and / or- the propelling liquid is at a concentration comprised between 60 wt.% and 97 wt.% with respect to the metallization liquid (10).

17. The method of any one of the above claims, wherein the substrate (30) is selected from one of a two-dimensional (2D) or a three-dimensional (3D) substrate, selected from one of a polyimide (PI), woven textile, a polyethylene terephthalate (PET), filter type substrate, a plastic substrate, a metal felt substrate, an aluminum substrate, preferably an aluminium foil, a ceramic substrate, a glass substrate, and a metal mesh substrate, preferably a titanium mesh.

18. The method of any one of the above claims, wherein the metallization liquid (10) comprises at least one additive selected from one of: organic molecules, polymers, conductive polymers, carbon nanotubes (CNT), densifiers, and surfactants.

19. A metallic coating (20) obtained after the method of any one of the above claims is a polycrystalline metal layer.

20. The metallic coating (20) of claim 19, wherein the metallic coating (20) has a thickness comprised between 2 nm and 500 nm, preferably between 2 nm and 100 nm.

21. The metallic coating (20) of claims 19 or 20, further comprising metal oxides, preferably the metal oxides are selected from any one of silver oxide, copper oxide, nickel oxide, zinc oxide, indium oxide, titanium oxide, iron oxide, zirconium oxide, niobium oxide, osmium oxide, iridium oxide ruthenium oxide, rhodium oxide, aluminum oxide, tin oxide, and antinomy oxide, preferably titanium oxide (TiCh), and niobium pentoxide (bt^Os).

22. The metallic coating (20) of any one of claims 19 to 21, wherein the metallic coating (20) has a print resistivity of at least 1 ohm / sq, preferably at least 4 ohm / sq, more preferably at least 5 ohm / sq; and / or a dielectric constant at 25°C of at least 20, preferably of at least 35.

23. Use of the metallic coating (20) of any one of claims 19 to 22 in an antibacterial application, electronic application, catalytic application, energy application.

24. Use of the metallic coating (20) of any one of claims 19 to 23 as a biological sensor, as a part of a bioelectronic sensor, in preparation of electrolyzers, in preparation of energy storage devices, preferably fuel cells, as part of a porous transport membrane, as a seed layer for future electroless or electroplating, a part of a solar panel device.

25. A metallization liquid (10) comprising at least one metal ionic precursor, at least one structuring liquid, and at least one propelling liquid, wherein the at least one metal ionic precursor comprises at least one metal cation and at least one counterion; the at least one structuring liquid for dissolving the at least one metal ionic precursor in the metallization liquid (10); and the at least one propelling liquid for nebulizing the metallization liquid (10), preferably the at least one structuring liquid is a solvent, and the solubility of the at least one metal ionic precursor in the solvent is at least 15 mg / ml at 25°C; and / or preferably the propelling liquid is a solvent having a dynamic viscosity at 25°C of between 0.5 mPa.s and 5 mPa.s.

26. The metallization liquid (10) of claim 25, wherein the at least one metal cation is selected from any one of Au, Ag, Pt, Pd, Cu, Ti, Nb, Ni, Co, Ru, Ir, and Rh; and the at least one counterion is selected from the group consisting of any of M(N03)n, HmMCln+m, and MN, where "M" is a metal atom, with a valence of "n", H is hydrogen, NO3 is nitrate, "N" comprises an oxalate, hydroxide, ketone, carboxyl, lactone, and "m" is a valence of the counterion.

27. The metallization liquid (10) of claim 25 or 26, wherein the at least one metal ionic precursor is at a concentration of at most 25 wt.% with respect to the at least one structuring liquid and the at least one propelling liquid, preferably between 1 and 15 wt.%, more preferably between 5 and 10 wt.% with respect to the at least one structuring liquid and the at least one propelling liquid.

28. The metallization liquid (10) of any one of claims 25 to 27, wherein the at least one structuring liquid is a solvent, and the solubility of the at least one metal ionic precursor in the solvent is at least 50 mg / ml at 25°C, preferably at least 100 mg / ml at 25°C.

29. The metallization liquid (10) of any one of claims 25 to 28, wherein the at least one structuring liquid is selected from one glycols, glycol ethers, glycol esters, carbonate esters, water, ketones, sulfoxides and their derivatives, or a combination thereof.

30. The metallization liquid (10) of any one of claims 25 to 29, wherein the at least one propelling liquid is selected from one of alcohol, cyclic alcohols, toluene, dioxane, ethylamines, glycol ethers, acetonitrile and their derivatives, or a combination thereof.

31. The metallization liquid (10) of any one of claims 25 to 30, wherein- the structuring liquid is at a concentration comprised between 3 wt.% and 40 wt.% with respect to the metallization liquid (10); and / or- the propelling liquid is at a concentration comprised between 60 wt.% and 97 wt.% with respect to the metallization liquid (10).

32. The metallization liquid (10) of any one of claims 25 to 31, further comprising at least one additive selected from one of: organic molecules, polymers, conductive polymers, carbon nanotubes (CNT), densifiers, and surfactants.

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