Coating having double layer arrangement

Abstract

The film includes a substrate and a coating deposited on the substrate. The coating includes a plurality of bilayers, each including two layers of different materials. Each of the two layers of different materials may comprise an oxide, a metal oxide, an alkoxide, an MLD method metal inorganic-organic hybrid, or an oxynitride. The thickness of each of the two layers of different materials may be from about 3 nanometers to about 30 nanometers. The thickness of the coating may be from about 20 nanometers to about 100 nanometers. The film with its nanoscale coating may be used in food packaging and other applications.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to U.S. Provisional Patent Application No. 63 / 457,626, filed April 6, 2023, which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to coatings and the deposition of coatings on films, particularly nanoscale coatings. Background Technology

[0004] Coatings are used on flexible materials for a wide range of packaging applications. Examples include, but are not limited to, coatings that protect the product contained in the packaging (e.g., food) from external factors, coatings that provide antimicrobial properties (e.g., packaging for health products), and coatings for other purposes.

[0005] Barrier coatings can be used on flexible packaging materials to protect products from external factors, including but not limited to water vapor, water, oxygen, light, aroma, oils, and foreign matter. Protection from these external factors can extend the shelf life of a product and ensure its safety for use or consumption. Summary of the Invention

[0006] According to one aspect of this disclosure, the membrane includes a substrate and a coating deposited on the substrate. The coating includes a plurality of bilayers, each bilayer comprising two layers of different materials.

[0007] Each of the two layers of different materials may contain oxides, metal oxides, alkoxides, MLD-processed metal-inorganic hybrids (metalcones), or oxynitrides.

[0008] Each double layer may include an aluminum oxide layer and a zinc oxide layer.

[0009] The double-layered alumina layer adjacent to the substrate can contact the substrate.

[0010] At least two of the multiple double layers can have a uniform thickness.

[0011] At least two of the multiple double layers can have different thicknesses.

[0012] In at least one of a plurality of double layers, the two layers of different materials may have a uniform thickness.

[0013] In at least one of a plurality of double layers, the two layers of different materials may have different thicknesses.

[0014] The number of multiple double layers can be from 2 to 12.

[0015] Each of the two layers of different materials can have a thickness of about 3 nanometers to about 30 nanometers.

[0016] The coating can have a thickness of about 20 nanometers to about 100 nanometers.

[0017] The layer of the coating in contact with the substrate can be thicker than other layers of the coating.

[0018] The film can further include an additional substrate including a substrate and an ink layer disposed on the substrate, and an adhesive layer adhering the additional substrate to the coating.

[0019] The substrate can include a substrate and an ink layer, and the coating can be deposited on the ink layer.

[0020] The film can further include an additional substrate and an adhesive layer adhering the additional substrate to the coating.

[0021] The substrate can include a substrate on which the coating is deposited, and the packaging film can further include an ink layer disposed on the coating.

[0022] The film can further include an additional substrate and an adhesive layer adhering the additional substrate to the ink layer.

[0023] The substrate can include a substrate and a pre-coating layer, and the coating can be deposited on the pre-coating layer.

[0024] The film can further include a top coating layer disposed on the coating.

[0025] The substrate can include polylactic acid.

[0026] The substrate can include paper.

[0027] The film can further include a laminated structure.

[0028] The two layers of different materials can be formed using a co-reactant or an oxidizing agent.

[0029] The film can be a food packaging film.

[0030] According to another aspect of the disclosure, a film includes a substrate and a coating deposited on the substrate. The coating includes a plurality of bilayers, each bilayer including two layers of different materials. Each of the two layers of different materials includes an oxide, a metal oxide, an oxyalkide, an MLD process metal inorganic-organic hybrid, or an oxynitride. Each of the two layers of different materials has a thickness of about 3 nanometers to about 30 nanometers. The coating has a thickness of about 20 nanometers to about 100 nanometers.

[0031] The layer of the coating in contact with the substrate can be thicker than other layers of the coating.

[0032] According to another aspect of the disclosure, a method of fabricating a film includes depositing layers of two different materials alternately onto a substrate to form bilayers. The bilayers have a nanoscale thickness. The method also includes forming a plurality of bilayers sequentially to form a coating on the substrate. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A cross-sectional view of an example film including a barrier coating disposed on a substrate, where the barrier coating includes bilayers, where each bilayer has layers of two different materials.

[0034] Figure 2 A cross-sectional view of an example film including a barrier coating and a substrate, an ink layer, and an adhesive layer on both sides.

[0035] Figure 3 A cross-sectional view of another example film including a barrier coating and a substrate, an ink layer, and an adhesive layer on both sides.

[0036] Figure 4 A cross-sectional view of another example film including a barrier coating and a substrate, an ink layer, and an adhesive layer on both sides.

[0037] Figure 5 A cross-sectional view of an example film including a barrier coating and a topcoat and a precoat.

[0038] Figure 6 A cross-sectional view of another example film including a barrier coating and a precoat.

[0039] Figure 7 A cross-sectional view of another example film including a barrier coating and a topcoat.

[0040] Figure 8 A cross-sectional view of an example bilayer arrangement of a barrier coating having a thicker first layer.

[0041] Figure 9 A cross-sectional view of another example bilayer arrangement of bilayers having different thicknesses.

[0042] Figure 10 A cross-sectional view of another example bilayer arrangement of layers of materials having different thicknesses within a bilayer.

[0043] Figure 11 A diagram showing a spatial atomic layer deposition (SALD) process for depositing a barrier coating.

[0044] Figure 12 A diagram showing a SALD apparatus for depositing a barrier coating. DETAILED DESCRIPTION

[0045] Disclosed herein are films, coatings, and methods of making the same, particularly, films having nanoscale, coatings, and methods of making the same. The technology discussed herein aims to provide a durable and resilient coating to improve coating performance.

[0046] Figure 1 An example film 100 is shown having a coating 102 disposed on a substrate 104. The coating 102 is a barrier coating, and the examples provided herein relate to barrier coatings. While the technology discussed herein is particularly suitable for barrier coatings, they are not limited to barrier coatings.

[0047] The film 100 can be used for packaging, such as food packaging (e.g., a sealed bag or package containing food or raw materials such as snacks, meats, cheeses, etc.), personal care products (e.g., creams, lotions, gels, etc.), pharmaceuticals, sterile medical products or equipment, agricultural products, and similar products that benefit from protection against degradation or contamination and / or require a relatively long shelf life. The substrate provides mechanical strength to the film 100, and the barrier coating 102 provides a barrier to substances that might otherwise enter or pass through the substrate 104 (e.g., oxygen, water, gases, particles, contaminants, etc.). The barrier coating 102 is deposited onto the substrate 104 by spatial atomic layer deposition (SALD).

[0048] Packaging is a suitable application for the technology discussed herein, but is not the only application. Accordingly, the present disclosure is not limited to packaging films. It should be apparent that the teachings and examples provided herein relating to packaging films can be used or readily adapted for use in other applications.

[0049] The substrate 104 is flexible and can include a base material such as polylactic acid (PLA), paper, paperboard, polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyurethane (PU), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), starch-based polymers, seaweed-based polymers, or the like. The substrate 104 can include additional materials or layers thereof, such as an ink layer or a pre-coat layer (also referred to as a primer). The substrate 104 can be selected to be biodegradable, recyclable, or compostable.

[0050] It is contemplated that a substrate 104 having roughness features with peak or valley sizes less than about 0.2 millimeters can be used without too much difficulty.

[0051] It is contemplated that if the substrate 104 has a pinhole, the pinhole should have a nominal width of less than about 10 nanometers so that the barrier coating 102 can reliably close the pinhole.

[0052] Useful substrates 104 can have a wide range of surface chemistries. Oxygen (O) groups at the surface are particularly useful. The precursor chemicals used in forming the barrier coating 102 can react with the O groups, which facilitates coating deposition. Examples of substrates and primers having such O groups include, for example, PLA, PET, polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), and acrylics.

[0053] The substrate 104 need not be specially treated to improve surface energy, as it is found that the barrier coating 102 adheres satisfactorily to the substrate 104 without such treatment.

[0054] In-line surface treatment can help remove dust and particles to improve surface cleanliness and prevent pinhole formation. Example surface treatments (also referred to as pre-treatments) include corona treatment, plasma treatment (e.g., argon plasma), and flame treatment. Pre-treating the surface prior to applying the barrier coating 102 can help with coating deposition by, for example, smoothing the surface in a manner that improves adhesion of the coating 102. The barrier coating 102 can conformally coat the surface and encapsulate any dust particles, and thus surface treatment can be used, but is not expected to be necessary in many cases.

[0055] With respect to the thermal mechanical properties of the substrate 104, in many examples it is useful if the substrate does not significantly bulge when heated. The substrate should retain its shape without deforming, at least up to the desired coating temperature. The glass transition temperature of the substrate should desirably be higher than the coating temperature. A lower coefficient of thermal expansion (CTE) of the substrate tends to reduce the chance of thermal stress cracking of the barrier coating 102 due to CTE mismatch between the barrier coating 102 and the substrate 104. In various examples, the substrate 104 material is selected to have a CTE that is consistent with or lower than the CTE of PP, PE, PLA, PVOH, or PU.

[0056] The barrier coating 102 includes a stack of bilayers 106. Any suitable number of bilayers 106 can be used. In various examples, 2 to 12 bilayers can be stacked to form the barrier coating 102.

[0057] Each bilayer includes two layers 108, 110 of different materials. The term “two” and similar terms used herein are open-ended, unless otherwise specified. In this example, two layers means two or more layers, and a bilayer can be three layers, etc.

[0058] The particular bilayer 106 design can be repeated to form a stack of bilayers 106 that forms the barrier coating 102. The repetition of bilayers 106 provides robustness in that a particular material layer 108, 110 can crack or exhibit imperfections without compromising the integrity of the barrier coating 102 as a whole. Multiple material layers 108, 110 can experience localized failure, but still provide an effective coating overall.

[0059] In various examples, each bilayer 106 can have a thickness of about 3 nanometers to about 30 nanometers. More specifically, each bilayer 106 can have a thickness of about 4 nanometers to about 14 nanometers. In various examples, the total thickness of the barrier coating 102 can be about 20 nanometers to about 100 nanometers. More specifically, the total thickness of the barrier coating 102 can be about 30 nanometers to about 90 nanometers.

[0060] The bilayers 106 generally have the same material layers 108, 110, although the thickness of the materials 108, 110 in the bilayers 106 can vary. For example, the material layer in contact with the substrate 104 can be thicker than the other material layer not in contact with the substrate 104. Such a thicker material layer can help to even out the surface roughness of the substrate 104 to promote barrier coating effectiveness. A thicker first layer can also be used to begin forming the intended multi-layer coating after fewer layers, as the first layer can penetrate into the substrate rather than forming a neat layer. That is, the first layer can be provided at a greater nominal thickness than would otherwise be required for the bilayer arrangement intended, to account for substrate roughness or unpredictability in initial deposition on the substrate. If the first layer is too thin, it can compromise the intended build of the subsequent layer or layers. In this sense, the first layer can be considered a mechanical buffer between the substrate and the rest of the coating.

[0061] Each material layer 108, 110 can comprise an oxide, a metal oxide, an alkoxide, an MLD process metal inorganic-organic hybrid (e.g., an "MLD process alucone" or "MLD process zincone"), an oxynitride, or similar material. For example, each bilayer 106 can include an aluminum oxide layer 108 and a zinc oxide layer 110. The aluminum oxide can act as a primary gas barrier material. The zinc oxide can act as a structural layer and can provide other benefits, such as ultraviolet (UV) light blocking. In various examples, the bilayers 106 can be configured and arranged such that the aluminum oxide layer 108 contacts the substrate 104. In other examples, the bilayers 106 can be configured and arranged such that the zinc oxide layer 110 contacts the substrate 104, which can improve barrier performance to moisture. The substrate-contacting layer, which can be referred to as a nucleation layer, can be thicker than the other layers. In yet other examples, other materials can be used, such as tin oxide, silicon oxide, and titanium dioxide.

[0062] Figure 2 An example film 200, such as a packaging film, is shown using the barrier coating 102 discussed above.

[0063] The barrier coating 102 is applied to a first substrate, which includes a substrate 202, such as paper, PLA, etc. (see above for more examples). The barrier coating 102 can be deposited directly onto the substrate 202.

[0064] The film 200 includes a second substrate, which includes a substrate 204 and an ink layer 206 disposed on the substrate 204. The substrate 204 can be paper, PLA, etc. (see above for more examples). The ink layer 206 can be printed onto the substrate 204. The ink layer 206 can not completely cover the substrate 204. That is, the ink can be selectively deposited to form images and text, leaving portions of the substrate 204 exposed.

[0065] The film 200 also includes an adhesive layer 208 that adheres the second substrate formed by the substrate 204 and the ink layer 206 to the barrier coating 102. The adhesive layer 208 joins the first substrate (i.e., the substrate 202) and the barrier coating 102 to the second substrate (i.e., the substrate 204 and the ink layer 206). The adhesive layer 208 can be applied after the two portions of the film 200 are separately completed.

[0066] Figure 3 An example film 300, such as a packaging film, is shown using the barrier coating 102 discussed above.

[0067] The film 300 includes a first substrate, which includes a substrate 302 and an ink layer 304. The substrate 302 can be paper, PLA, etc. (see above for more examples). The ink can be printed onto the substrate 302 to form the ink layer 304. Depending on the amount printed, the ink layer 304 can not completely cover the substrate 302.

[0068] The barrier coating 102 is deposited on the first substrate. More specifically, the barrier coating 102 is deposited onto the ink layer 304 and onto any portions of the substrate 302 that are not covered by the ink layer 304.

[0069] The film 300 includes a second substrate, which includes a substrate 306, such as paper, PLA, etc. (see above for more examples).

[0070] An adhesive layer 308 adheres the first substrate (i.e., the substrate 302 and the ink layer 304) and the barrier coating 102 to the second substrate (i.e., the substrate 306). The adhesive layer 308 can be applied after the two portions of the film 300 are separately completed.

[0071] Figure 4An example film 400, such as a packaging film, is shown using the barrier coating 102 discussed above.

[0072] The film 400 includes a first substrate including a substrate 402, such as paper, PLA, or the like (see above for more examples). The barrier coating 102 can be deposited directly onto the substrate 402.

[0073] The film 400 includes an ink layer 404 disposed on the barrier coating 102. The ink can be printed onto the barrier coating 102 to form the ink layer 404. Depending on the amount printed, the ink layer 404 can not completely cover the barrier coating 102.

[0074] The film 400 also includes a second, additional substrate including a substrate 406, such as paper, PLA, or the like (see above for more examples).

[0075] The adhesive layer 408 adheres the second substrate to the first substrate. That is, the adhesive layer 408 adheres the substrate 406 to the ink layer 404 and any portion of the barrier coating 102 not covered by the ink layer 404. The adhesive layer 408 can be applied after the two portions of the film 400 are separately completed.

[0076] The example films 200, 300, 400 can also include a heat seal layer, such as a PE layer, applied to the exposed face of the substrate to facilitate heat sealing closure of the packaging. Good sealing is important to avoid leaks, intrusion, contamination, which would defeat the purpose of the barrier coating.

[0077] The example films 200, 300, 400 can be considered 2-ply films, as each substrate and its attendant layers form one ply. In other examples, similar films can be provided with any suitable number of additional layers, such as plastic, aluminum foil, or layers of functionalized films, to form 3-ply or 4-ply films that provide similar utility and benefits.

[0078] Figure 5 An example film 500, such as a packaging film, is shown using the barrier coating 102 discussed above.

[0079] The film 500 includes a substrate including a substrate 502 and a pre-coat layer 504.

[0080] Barrier coating 102 is deposited on a pre-coat 504 (which can be referred to as a primer). Pre-coat 504 can be used to fill holes in the paper substrate, to create a smooth and uniform layer for barrier coating 102, to provide a compatible surface chemistry for the barrier coating (e.g., a primer with oxygen groups when the barrier coating 102 includes a metal oxide). Example materials for pre-coat 504 include PVOH, EVOH, acrylic, polyurethane (PU), nanocellulose / microfibrillated cellulose, PLA coating, PE coating, or the like.

[0081] Film 500 also includes a top coat 506 disposed on the barrier coating 102. Top coat 506 can be used to protect barrier coating 102 from downstream processes, such as transport. For example, if barrier coating 102 contacts a roller, it can be damaged (e.g., scratched). A suitable top coat 506 can prevent such damage. A suitable top coat 506 can improve the resistance of barrier coating 102 to flexural damage.

[0082] Top coat 506 can also provide separation from particulate matter present in the ink that can damage barrier coating 102. Thus, in this example and other examples where barrier coating 102 contacts ink (see Figures 2 to 4 ), a top coat 506 can be disposed on barrier coating 102 to prevent such damage.

[0083] Example top coats 506 include PE layers for heat sealing and other materials discussed above that can be used for pre-coat 504.

[0084] In various examples, top coat 506 can be made of the same material as substrate 502, which improves recyclability.

[0085] Example film 500 can be considered a 1 -layer film. In other examples, similar films can be provided with any suitable number of additional layers, such as layers of plastic, aluminum foil, or functionalized films, to form 2-layer, 3 -layer, or 4-layer films that provide similar utility and benefits.

[0086] Figure 6 An example film 600, such as a packaging film, is shown using barrier coating 102 discussed above. For details not repeated here, reference can be made to the description of film 500 above.

[0087] Film 600 includes a base including substrate 502 and pre-coat or primer 504. Barrier coating 102 is deposited on substrate 502, i.e., onto pre-coat or primer 504.

[0088] Figure 7 An example film 700, such as a packaging film, is shown using barrier coating 102 discussed above. For details not repeated here, reference can be made to the description of film 500 above.

[0089] The film 700 includes a substrate 502 without a pre-coating or primer 504. A barrier coating 102 is deposited on the substrate 502. A topcoat 506 is deposited on the base barrier coating 102.

[0090] about Figures 2 to 7 The examples provided herein should be considered in light of other examples from which they can be derived. Furthermore, various known pre-coating and topcoat materials provide a degree of barrier properties. The barrier coating 102 described herein can be used in combination with such materials to further enhance barrier performance.

[0091] Still about Figures 2 to 7 The examples provided can be further enhanced with laminated structures, topcoat sealants, or the like. For instance, using an industrial lamination process to laminate a PE layer into this example can help protect the barrier coating, especially where the barrier coating is exposed, such as in... Figure 6 In some examples. Alternatively, a varnish layer, such as an acrylic layer, can be applied using flexographic or screen printing. A topcoat or laminate is made from the same material as the substrate (see, for example, see...). Figure 5 and Figure 7 Layer 506 in the middle can provide advantages for recycling purposes.

[0092] Figures 8 to 10 Further details of the example double layer are shown, illustrating the example thickness. These examples demonstrate that variable material thickness is possible and may be desirable in certain applications.

[0093] Figure 8 An arrangement 800 of a uniform bilayer 802 having repeating first material 108 and second material 110 is shown. Except for an initial layer 804 of first material 108 which is thicker to promote adhesion to substrate 104, each material layer of the bilayer 802 is deposited with the same nominal thickness (e.g., 5 nm).

[0094] Figure 9 An arrangement 900 of variable bilayers 902, 904 having a first material 108 and a second material 110 is shown. Each bilayer 902, 904 has material layers 108, 110 with the same nominal thickness (e.g., 4 nm or 5 nm), and this thickness can vary between the bilayers 902, 904.

[0095] Figure 10 An arrangement 1000 of a double layer 1002 having a first material 108 and a second material 110 having different nominal thicknesses (e.g., 3 nm and 5 nm) is shown.

[0096] Figures 8 to 10The principles illustrated in the middle can be combined to meet the needs of various applications. Generally, the bilayers can have uniform or different thicknesses, and the material layers forming the bilayers can have consistent or variable thicknesses in different bilayers.

[0097] Referring Figure 11 The barrier coating 102 discussed herein can be deposited onto a substrate using SALD. An example SALD process generally includes sparging a working gas (e.g., a precursor gas, a reactant gas, an inert gas, etc.) via one or more slits 1100 and exhausting exhaust gas via one or more slits 1102, where the slits 1100, 1102 are in communication with a network of channels within a structure that can be referred to as a SALD coater or head. This reduces or eliminates the need for the evacuation and purge steps that make traditional ALD slow, making SALD one to two orders of magnitude faster than conventional ALD. SALD can produce ultrathin coatings of dense, conformal, and pinhole-free materials (e.g., metal oxides) and can deposit coatings under open air conditions and pressures and at room or cryogenic temperatures without the need for a vacuum chamber. SALD is scalable and compatible with roll-to-roll manufacturing and has been proven to work on a variety of surfaces, including but not limited to plastics and paper. More information on ALD and SALD can be found in PCT Publication WO2021119829, entitled “Apparatus and Method for Thin Film Deposition,” filed December 18, 2020, which is incorporated by reference herein.

[0098] Figure 12 An example spatial atomic layer deposition apparatus 1200 operable to deposit the barrier coating 102 is shown. The apparatus 1200 includes a SALD head 1202, a conveyance system 1204, and a gas delivery system 1206. A heater 1208 can be provided at the SALD head 1202. Any suitable combination of gases delivered through the gas delivery system 1206 can be used with any suitable number of SALD heads 1202 to deposit the barrier coating 102 on a flexible substrate conveyed by the conveyance system 1204 past the SALD head 1202. The flexible substrate can be conveyed in one or both directions past one or more SALD heads 1202 to build the barrier coating 102.

[0099] The transport system 1204 can include rollers 1210, web guides 1212, pinch rollers 1213, idlers 1214, conditioning rollers 1216, load cells 1218, and similar components positioned between an unspooler 1220 and a spooler 1222 to transport a flexible substrate material 1224, such as a sheet or film of material (sometimes referred to as a "film," particularly in the packaging industry, but not to be confused with a film or coating being deposited). With the transport system 1204, the flexible substrate material 1224 can be unwound from a roll at the unspooler 1220, coated by the SALD head 1202, and wound onto another roll at the spooler 1222. The positioning of the rolls can be used to position the flexible material relative to the one or more SALD heads 1202, and can be used to control the distance between the surface of the flexible material 1224 and the surface of the SALD head 1202.

[0100] The gas delivery system 1206 includes containers 1230, 1232, 1234 of inert gas (e.g., nitrogen), precursor (e.g., trimethylaluminum Al(CH3)3, for aluminum oxide), and reactant (e.g., oxidizer such as H2O); mass flow controllers 1236; on-off valves 1238; and gas lines 1240 fluidically connecting these components. Each gas line 1240 can deliver pure inert gas, precursor, and reactant or a mixture of inert gas, precursor, and reactant to the SALD head 1202 at a flow rate controlled by the respective mass flow controller 1236 and on-off valve 1238. Figure 12 The configuration and arrangement of the components in FIG. 12 represent one example. In other examples, the components can have different configurations and arrangements.

[0101] Various reactants (also referred to as co-reactants) or oxidizers can be provided to react with a metal or a compound containing a metal (e.g., aluminum or zinc) to form a layer of a barrier coating. Examples of co-reactants and oxidizers include water, oxygen, ethylene glycol, and oxygen plasma, among others. The co-reactants / oxidizers can be alternating layers. For example, different co-reactants / oxidizers can be used for alternating materials of a bilayer. The co-reactants / oxidizers can help increase the density of certain layers.

[0102] Gas lines 1240 can be tubes made of chemically stable or inert materials (e.g., stainless steel or Teflon) that connect between components upstream of SALD head 1202. Such components can include inert gas containers 1230; containers (e.g., bubblers) holding chemicals 1232, 1234; mass flow controllers 1236; and on-off valves 1238. The gas delivery system 1206 is used to deliver one or more precursor gases, one or more reactant gases, and one or more inert gases to the SALD head 1202 in pure form or in suitable mixtures. Inert gas containers 1230 supply inert, non-reactive gases to the SALD head 1202 and can also be used to carry precursor gases from precursor gas containers 1234 and / or reactant gases from reactant gas containers 1232 to the SALD head 1202. The pressure of the inert gas can be regulated by one or more pressure regulators. The precursor and reactant gases can be generated by techniques such as, but not limited to, bubbling a liquid chemical with an inert gas; atomizing a liquid chemical by heating the liquid or solid chemical; direct liquid injection, in which a liquid chemical precursor is introduced into a vaporizer that vaporizes the liquid and ejects the gas from a nozzle; or combinations thereof. The chemical vapor can also be supplied in a gaseous state from a tank or generated by another device that can be used to generate the reactant gas, such as an ozone generator. The flow of inert gas, one or more precursor gases, and one or more reactant gases is controlled by mass flow controllers 1236 and on-off valves 1238 (e.g., manual diaphragm valves or pneumatic valves). The flow controllers 1236 and valves 1238 can be controlled manually or electronically by a control system.

[0103] In Figure 12 one or more SALD heads 1202 deliver precursors, reactants, and inert gases onto a flexible substrate material 1224. Head 1202 includes a plurality of internal gas channels that redirect and distribute the gases in appropriate arrangements onto the flexible material 1224 to induce SALD, as shown in Figure 11 Head 1202 includes any suitable number and configuration of slits 1250 to output the gases to the flexible substrate material 1224. Other components can be integrated into the one or more SALD heads 1202, including but not limited to cooling and heating elements and plasma sources. For example, one or more plasma sources can be embedded into the head to reduce the temperature required for coating deposition. According to Figure 12 One or more exhaust pumps 1242 are connected to the head 1202. The exhaust pump 1242 removes gases, such as unreacted precursors and / or reactants and inert gases, from the space between the operational surface 1244 of the head 1202 and the surface of the flexible material 1224.

[0104] exist Figure 12 As shown, heater 1208 can be used to heat flexible material 1224 to promote chemical reactions on the surface of flexible material 1224. In the example shown, heater 1208 spans the length of head 1202. Various heaters with different heating powers and different shapes and sizes (e.g., drum heaters on which flexible material is wound) can be provided. Furthermore, one or more heaters can be embedded in head 1202. Based on the mechanical positioning of the heaters, one or more heaters can also be used to control the position of the surface of the flexible material relative to one or more of the SALD heads 1202. One or more of the rollers of conveying system 1204 can be heated to control the temperature of flexible material 1224.

[0105] In other instances, one or more sheets of flexible material may be mounted on a translation stage that moves through the head in one or both directions relative to the coating process. The translation stage may be heated and may be used to control the distance between the surface of the flexible material and the surface of the SALD head 1202.

[0106] More information on examples of gas delivery systems, SALD heads, exhaust pumps, heaters, and translation stages can be found in PCT Publication WO2021119829.

[0107] It should be recognized that the features and aspects of the various examples provided above can be incorporated into other examples that also fall within the scope of this disclosure. Furthermore, the accompanying drawings are not drawn to scale and may be enlarged in size and shape for illustrative purposes.

Claims

1. A film comprising: a substrate; and a coating deposited on the substrate; wherein the coating comprises a plurality of bilayers, each bilayer comprising two layers of different materials.

2. The film of claim 1, wherein each of the two layers of different materials comprises: an oxide; a metal oxide; an alkoxide; an MLD process metal inorganic-organic hybrid; or an oxynitride.

3. The film of claim 1, wherein each bilayer comprises an aluminum oxide layer and a zinc oxide layer.

4. The film of claim 3, wherein the aluminum oxide layer of a bilayer adjacent to the substrate is in contact with the substrate.

5. The film of claim 1, wherein at least two of the plurality of bilayers have a uniform thickness.

6. The film of claim 1, wherein at least two of the plurality of bilayers have different thicknesses.

7. The film of claim 1, wherein, In at least one of the plurality of bilayers, the two layers of different materials have a uniform thickness.

8. The film of claim 1, wherein, In at least one of the plurality of bilayers, the two layers of different materials have different thicknesses.

9. The film of claim 1, wherein the number of the plurality of bilayers is from 2 to 12.

10. The film of claim 1, wherein the thickness of each of the two layers of different materials is from about 3 nanometers to about 30 nanometers.

11. The film of claim 1, wherein the thickness of the coating is from about 20 nanometers to about 100 nanometers.

12. The film of claim 1, wherein a layer of the coating in contact with the substrate is thicker than other layers of the coating.

13. The film of claim 1, further comprising: a further substrate comprising a substrate and an ink layer disposed on the substrate; and an adhesive layer adhering the further substrate to the coating.

14. The film of claim 1, wherein: the substrate comprises a substrate and an ink layer; and the coating is deposited on the ink layer.

15. The film of claim 14, further comprising: a further substrate; and an adhesive layer adhering the further substrate to the coating.

16. The film of claim 1, wherein: the substrate comprises a substrate on which the coating is deposited; and the packaging film further comprises an ink layer disposed on the coating.

17. The film of claim 16, further comprising: a further substrate; and an adhesive layer adhering the further substrate to the ink layer.

18. The film of claim 1, wherein: the substrate comprises a substrate and a pre-coating layer; and the coating is deposited on the pre-coating layer.

19. The film of claim 18, further comprising a top coating disposed on the coating.

20. The film of claim 1, wherein the substrate comprises polylactic acid.

21. The film of claim 1, wherein the substrate comprises paper.

22. The film of claim 1, further comprising a laminated structure.

23. The film of claim 1, wherein the two layers of different materials are formed using a co-reactant or an oxidizing agent.

24. The film of claim 1, wherein the film is a food packaging film.

25. A film, comprising: a substrate; and a coating deposited on the substrate, the coating comprising a plurality of bilayers, each bilayer comprising two layers of different materials; wherein each of the two layers of different materials comprises an oxide, a metal oxide, an alkoxide, an MLD method metal inorganic-organic hybrid, or an oxynitride; wherein each of the two layers of different materials has a thickness of about 3 nanometers to about 30 nanometers; and wherein the coating has a thickness of about 20 nanometers to about 100 nanometers.

26. The film of claim 25, wherein a layer of the coating in contact with the substrate is thicker than other layers of the coating.

27. A method of making a film, the method comprising: alternately depositing two layers of different materials onto a substrate to form a bilayer, wherein the bilayer has a nanoscale thickness; and sequentially forming a plurality of the bilayers to form a coating on the substrate.

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