Surface coatings configured to enhance UV sterilization and methods of making surface coatings

Abstract

A surface coating for enhancing UV sterilization and a method for manufacturing the surface coating are disclosed. The surface coating is configured to locally enhance the UV light intensity of UV light incident on the surface coating. The surface coating includes a dielectric layer, a conductive layer located on the dielectric layer, a series of nano-openings located in the dielectric layer and the conductive layer, a series of nano-antennas located in the series of nano-openings, and a dielectric gap located between the series of nano-antennas and the conductive layer. The conductive layer and the nano-antennas both include a UV plasma material.

Description

Technical Field

[0001] The present application generally relates to surface coatings configured to enhance UV sterilization and methods of making the same. Background Art

[0002] Ultraviolet (UV) light (200-320nm) is commonly used to sterilize surfaces against viral and microbial pathogens. UV light sterilizes surfaces by destroying the genetic material inside viruses and other microorganisms. In addition, UVC light (200-280nm), which is a specific band of UV light, is widely used for sterilization. For example, UVC lamps and robots are commonly used to clean water and air purifiers, clean objects such as laboratory equipment, and spaces such as buses and airplanes. UVB light (280-320nm) can also be used for sterilization, but compared to UVC light, UVB light requires high doses or longer exposure times for effective sterilization. Typical doses for effective sterilization are greater than 60mJ / cm for UVC light. 2 , for UVB light greater than 1000mJ / cm 2 .

[0003] However, exposure to UVC light is more dangerous to humans than exposure to UVB light, and existing UVC disinfectants are not safe for human exposure. According to EU health agency guidelines, human exposure to UVC light is below 3mJ / cm 2 Exposure to UVC light at higher doses and / or longer durations can damage the eyes and skin and may cause cancer. Summary of the Invention

[0004] The present application relates to various embodiments of surface coatings configured to locally enhance the UV light intensity of UV light incident on the surface coating. In one embodiment, the surface coating comprises: a dielectric layer; a conductive layer disposed on the dielectric layer; a series of nano-openings disposed in the dielectric layer and the conductive layer; a series of nano-antennas disposed in the series of nano-openings; and a series of dielectric gaps disposed between the series of nano-antennas and the conductive layer. Both the conductive layer and the series of nano-antennas comprise UV plasmonic material.

[0005] The dielectric gaps in the series of dielectric gaps have a distance of about 10 nm or less.

[0006] The UV plasma material may be aluminum (Al), gallium (Ga), indium (In), tin (Sn), thallium (Tl), lead (Pb), bismuth (Bi), magnesium (Mg), germanium (Ge), gallium nitride (GaN), or a combination thereof.

[0007] The dielectric layer may include polymethyl methacrylate (PMMA), silicon dioxide (SiO2), or a low-index dielectric material.

[0008] Each nanoantenna in the series of nanoantennas may have a circular, spherical, elliptical, prismatic (eg, square or rectangular), or conical shape.

[0009] The average diameter of the array of nanoantennas may be in a range from about 20 nm to about 500 nm.

[0010] At least one nanoantenna of the series of nanoantennas may have a shape or size that is different from a shape or size of another nanoantenna in the series of nanoantennas.

[0011] The periodicity of the series of nanoantennas may be in the range from about 50 nm to about 1,000 nm.

[0012] The plurality of nano-openings and the plurality of nano-antennas may be arranged to cover at least 60% of the surface coating.

[0013] A surface coating according to another embodiment of the present disclosure includes a layer of ultraviolet plasma material including a series of nanoantennas, and a dielectric pattern disposed in the layer of ultraviolet plasma material, wherein the dielectric pattern separates adjacent nanoantennas in the series of nanoantennas from each other by a dielectric gap.

[0014] The dielectric gap may have a distance of about 10 nm or less.

[0015] The UV plasma material can be Al, Ga, In, Sn, Tl, Pb, Bi, Mg, Ge, GaN, or a combination thereof.

[0016] The dielectric pattern may include an array of shapes such as grid lines, stripes, V-shaped lines, a sawtooth pattern, a cross pattern, and combinations thereof.

[0017] An average width of the array of nanoantennas may be in a range from about 20 nm to about 500 nm.

[0018] The present disclosure also relates to various methods for making surface coatings. In one embodiment, the method includes depositing a mixture of a first polymer and a second polymer on a substrate, wherein the second polymer self-arranges into a series of spots. The method also includes selectively removing the series of spots to form a series of nano-openings in a dielectric layer formed from the first polymer, and depositing a UV plasma material on the dielectric layer and in the series of nano-openings. The UV plasma material forms a series of nano-antennas in the series of nano-openings and forms a conductive layer on the dielectric layer.

[0019] The step of depositing the mixture may include brushing, spraying, dipping, vapor deposition or printing.

[0020] The step of depositing the UV plasma material may include electron beam evaporation, radio frequency (RF) sputtering, thermal sputtering, or molecular beam deposition of the UV plasma material.

[0021] The first polymer may include polymethyl methacrylate (PMMA), and the second polymer may include polystyrene (PS).

[0022] According to another embodiment of the present disclosure, the method includes depositing a UV plasma material on a substrate to form a series of first protrusions on the substrate, wherein the series of first protrusions are separated from each other by spaces. The method also includes depositing a dielectric material on the series of first protrusions and in the spaces between the series of first protrusions; depositing the UV plasma material to form a series of second protrusions in the spaces between the series of first protrusions and to form a series of excess protrusions on the series of first protrusions; removing the series of excess protrusions; and selectively removing portions of the dielectric material located on the series of first protrusions. The series of first protrusions and the series of second protrusions define nanoantennas of the conductive layer, and the remaining portion of the dielectric material defines a dielectric pattern.

[0023] The step of removing the series of excess protrusions may include applying an adhesive on the series of excess protrusions and peeling the adhesive and the series of excess protrusions adhered to the adhesive.

[0024] The present disclosure also relates to various embodiments of a method for sterilizing a surface comprising an array of nanoantennas and a array of dielectric gaps. In one embodiment, the method comprises irradiating the surface with ultraviolet light from an ultraviolet light source having a first dose that is safe for human exposure. During the irradiation of the surface with the ultraviolet light, the array of dielectric gaps locally increases the first dose of ultraviolet light to a second dose that is higher than the first dose, wherein the second dose is unsafe for human exposure.

[0025] The second dose can be at least about 1,000 times greater than the first dose.

[0026] This summary is provided to introduce a selection of features and concepts of the embodiments of the present disclosure that are further described in the detailed description below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. One or more of the described features can be combined with one or more other described features to provide a viable device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] These and other features and advantages of the embodiments of the present disclosure will become more apparent by reference to the following detailed description when considered in conjunction with the following drawings. In the drawings, like reference numerals are used throughout the drawings to refer to like features and components. The drawings are not necessarily drawn to scale.

[0028] Figure 1A to Figure 1B are a perspective view and a detailed cross-sectional view, respectively, of a surface coating including an array of nanoantennas according to one embodiment of the present disclosure;

[0029] Figure 2 is a color-coded diagram depicting the local electromagnetic field intensity at a nanoantenna according to one embodiment of the present disclosure;

[0030] Figure 3 depicts a scanning electron microscope (SEM) photograph showing viruses and / or other microbial pathogens attracted to a dielectric gap due to dielectrophoresis (DEP);

[0031] Figure 4 is a graph depicting how the local intensity enhancement factor of the surface coating varies with the diameter of the nanoantenna for incident UV light having a frequency ranging from 200 nm to 400 nm;

[0032] Figure 5 The present invention is a manufacturing method according to an embodiment of the present invention. Figure 1A to Figure 1B A flow chart of the steps of an embodiment of a method for surface coating is shown in FIG;

[0033] Figures 6A to 6C It shows that according to Figure 5 A perspective view of the steps of the method for making a surface coating shown in ;

[0034] 7A to 7B are a plan view and a cross-sectional view, respectively, of a surface coating including a series of nanoantennas according to another embodiment of the present disclosure;

[0035] Figure 8 The present invention is a manufacturing method according to an embodiment of the present invention. 7A to 7B A flow chart of the steps of an embodiment of a method for surface coating is shown in FIG;

[0036] Figures 9A to 9E It shows that according to Figure 8 A side view of the steps of manufacturing a surface coating according to the method shown in ; and

[0037] Figure 10 A sterilization system including a surface coating and a UV light source according to one embodiment of the present disclosure is disclosed. DETAILED DESCRIPTION

[0038] The present application relates to various embodiments of surface coatings and methods for preparing surface coatings, wherein the surface coating is configured to locally enhance the density of ultraviolet (UV) light when the surface coating is irradiated with a UV light source. In one or more embodiments, the surface coating includes an array of nanoantennas having a single resonance or a broadband resonance at the wavelength of the target UV light source. Thus, the surface coating can be irradiated with ultra-low power doses of UV light within safe human limits, and the surface coating can locally increase the density of the UV light and the local electromagnetic field, thereby effectively killing microbial and viral pathogens on the surface coating and accelerating the sterilization rate to achieve high-throughput performance. That is, the nanoantennas are configured to spatially confine the incident UV light to increase the effective dose of the incident UV light. In addition, in one or more embodiments, the surface coating is configured to scatter the UV light incident on the surface coating over a wide range of angles (e.g., the surface coating exhibits omnidirectional light enhancement properties), which enhances light-matter interaction to effectively kill pathogens on the surface coating.

[0039] Hereinafter, example embodiments will be described in more detail with reference to the accompanying drawings, in which like reference numerals refer to like elements throughout. However, the present invention may be implemented in various different forms and should not be construed as being limited to the embodiments shown only herein. On the contrary, these embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey the aspects and features of the present invention to those skilled in the art. Therefore, unnecessary processes, elements, and techniques for fully understanding the aspects and features of the present invention for those of ordinary skill in the art may not be described. Unless otherwise stated, like reference numerals represent like elements in all drawings and written descriptions, and therefore, descriptions thereof may not be repeated.

[0040] In the accompanying drawings, for the sake of clarity, the relative sizes of elements, layers and regions may be exaggerated and / or simplified. For ease of explanation, spatial relative terms such as "under...", "below...", "below...", "below...", "above...", "on...", etc. may be used to describe the relationship between an element or feature and another (multiple) element or feature as shown in the drawings. It will be understood that the spatial relative terms are intended to include different orientations of the device in use or operation except for the orientation depicted in the drawings. For example, if the device in the drawings is flipped, the element described as "under" or "under" or "under" other elements or features will then be positioned as "above" the other elements or features. Therefore, the example terms "under..." and "under..." can include both above and below orientations. The device can be positioned otherwise (e.g., rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein should be interpreted accordingly.

[0041] It will be understood that although the terms "first," "second," "third," etc. may be used herein to describe various elements, components, regions, layers, and / or parts, these components, assemblies, regions, layers, and / or parts should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Therefore, the first element, first component, first region, first layer, or first part described below may be named as the second element, second component, second region, second layer, or second part without departing from the spirit and scope of the present invention.

[0042] It will be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it can be directly on, directly connected to, or directly coupled to the other element or layer, or one or more intervening elements or layers may be present. Additionally, it will be understood that when an element or layer is referred to as being “between” two elements or layers, it can be the only element or layer between the two elements or layers, or one or more intervening elements or layers may also be present.

[0043] The terms used herein are for the purpose of describing specific embodiments and are not intended to limit the present invention. As used herein, unless the context clearly indicates otherwise, the singular "one" and "one (kind / person)" are also intended to include plural forms. It will also be understood that the terms "comprise", "include" and / or their variations are used in this specification to illustrate the presence of stated features, integral bodies, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integral bodies, steps, operations, elements, components and / or their groups. As used herein, the term "and / or" includes any combination and all combinations of one or more of the relevant listed items. Expressions such as "at least one (kind / person) in ... " modify the entire row of elements when following a row of elements, rather than modifying the individual elements listed.

[0044] As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation rather than terms of degree, and are intended to account for the inherent variation in measured or calculated values that would be recognized by one of ordinary skill in the art. Furthermore, the use of "may" when describing embodiments of the present invention refers to "one or more embodiments of the present invention." As used herein, the term "use" and variations thereof may be considered synonymous with the term "utilizing" and variations thereof, respectively. Furthermore, the term "exemplary" is intended to indicate an example or illustration.

[0045] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. It will also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and / or this specification, and should not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0046] Figure 1A to Figure 1BA surface coating 100 according to one embodiment of the present disclosure is depicted. The surface coating 100 can be applied to a substrate S of any suitable article or fixture that is desired to be sterilized against microbial and viral pathogens (e.g., an air conditioning filtration system, a high-touch surface such as an elevator button, door handle, and door pull handle, and / or any other surface that may facilitate the spread of pathogens). In the illustrated embodiment, the surface coating 100 includes a dielectric layer 101, a conductive layer 102 positioned on the dielectric layer 101, a series (i.e., a plurality) of nano-openings 103 (e.g., nanopores or nanocavities) extending through the conductive layer 102 and the dielectric layer 101, and a series (i.e., a plurality) of nano-antennas 104 positioned in the nano-openings 103. In the illustrated embodiment, the nano-antennas 104 are recessed in the nano-openings 103. Additionally, in the illustrated embodiment, each nano-antenna 104 is recessed in the nano-opening 103 below the interface between the upper surface 105 of the dielectric layer 101 and the lower surface 106 of the conductive layer 102. Thus, in the illustrated embodiment, the nanoantennas 104 are separated from the conductive layer 102 by a portion of the dielectric layer 101 (i.e., the nanoantennas 104 are separated from the conductive layer 102 by a dielectric gap G). In one or more embodiments, the dielectric gap G between the nanoantennas 104 and the conductive layer 102 can be approximately 10 nm or less (i.e., in the illustrated embodiment, the nanoantennas 104 are recessed in the nano-openings 103 such that the distance between the upper surface of each nanoantenna 104 and the lower surface 106 of the conductive layer 102 along the dielectric layer 101 is approximately 10 nm or less). In one or more embodiments, the dielectric gap G between the nanoantennas 104 and the conductive layer 102 can be approximately 5 nm or less.

[0047] The conductive layer 102 and the nano-antenna 104 can be formed of any UV plasma material or combination of UV plasma materials, such as metals (e.g., aluminum (Al), gallium (Ga), indium (In), tin (Sn), thallium (Tl), lead (Pb), bismuth (Bi), and / or magnesium (Mg)) or metalloids (e.g., germanium (Ge)). In one or more embodiments, the conductive layer 102 and the nano-antenna 104 can be formed of gallium nitride (GaN) or aluminum nitride (AlN).

[0048] In addition, in the illustrated embodiment, the nano-opening 103 and the nano-antenna 104 in the nano-opening 103 are circular, and the diameters of the nano-opening 103 and the nano-antenna 104 are in a range from about 20 nm to about 500 nm. In one or more embodiments, the nano-opening 103 and the nano-antenna 104 may have any other suitable shape, such as a cone, an oval, an ellipse, a sphere, or a prism (e.g., a square or a rectangle).

[0049] In the illustrated embodiment, the nanoantennas 104 can be spaced apart from adjacent nanoantennas 104 by a distance D ranging from about 50 nm to about 1,000 nm (e.g., the array of nanoantennas 104 can have a periodicity ranging from about 50 nm to about 1,000 nm). In one or more embodiments, the nano-openings 103 and corresponding nanoantennas 104 can be disposed along any suitable portion of the surface coating 100 (such as, for example, about 60% or more of the surface coating 100).

[0050] In use, when UV light (e.g., UVC and / or UVB light) is incident on the surface coating 100, coupling between photons in the incident UV light and free electrons on the surface of the conductive layer 102 and the surface of the nanoantenna 104 (i.e., free electrons in the UV plasma material) causes the free electrons to flow toward the dielectric gap G (i.e., the free electrons flow toward the dielectric interface between the conductive layer 102 and the nanoantenna 104). The dielectric gap G between the conductive layer 102 and the nanoantenna 104 restricts the flow of free electrons between the conductive layer 102 and the nanoantenna 104, which results in an accumulation of electrons at the dielectric gap G. This accumulation of electrons traps an electric field in the dielectric gap G, thereby locally increasing the electromagnetic field strength at the dielectric gap G. That is, when UV light is incident on surface coating 100, free electrons in the UV plasma material of nanoantenna 104 flow radially outward toward dielectric gap G, while free electrons in the UV plasma material of conductive layer 102 flow toward the edges of nano-opening 103. This traps the electric field in dielectric gap G and locally increases the electromagnetic field intensity at dielectric gap G due to a capacitive effect. Generally, reducing the size of dielectric gap G between nanoantenna 104 and conductive layer 102 increases the local enhancement of the electromagnetic field intensity at dielectric gap G. For example, in one or more embodiments, dielectric gap G between nanoantenna 104 and conductive layer 102 is configured to locally increase the effective dose of UV light incident on surface coating 100 by greater than approximately 1,000 times. In one or more embodiments, dielectric gap G between nanoantenna 104 and conductive layer 102 is configured to locally increase the effective dose of UV light incident on surface coating 100 by a factor ranging from approximately 500 to approximately 1,500 or more.

[0051] Figure 2 is a color-coded graph depicting the local electromagnetic field intensity (E) at the nano-antennas 104 of the surface coating 100 according to one embodiment of the present disclosure. Figure 2 In FIG, the portion of the nano-antenna 104 shown in light gray exhibits a relatively high local electromagnetic field intensity, and the portion of the nano-antenna 104 shown in dark gray exhibits a relatively low local electromagnetic field intensity. Figure 2As shown in FIG, when the UV light source used to irradiate the surface coating is a UV light source with a frequency of about 250 nm and a dose of about 1 mJ / cm 2 When the UVC light is applied, the maximum local effective dose of UV light at the dielectric gap G between the nano-antenna 104 of the surface coating 100 and the conductive layer 102 increases to about 1,334 mJ / cm 2 (That is, the dielectric gap G between the nano-antennas 104 of the surface coating 100 and the conductive layer 102 is configured to locally increase the effective dose (electromagnetic density) of UV light incident on the surface coating 100 by more than 1,000 times.) Thus, in one or more embodiments, a dose of UV light that is safe for human exposure but insufficient to destroy viruses or other microbial pathogens (e.g., a dose of about 3 mJ / cm 2 or less UVC light) can be directed toward the surface coating 100, and the intensity of the UV light can be locally enhanced at the dielectric gap G to a dose sufficient to destroy the genetic material inside the viruses and / or other microorganisms on the surface coating 100.

[0052] Additionally, in one or more embodiments, viral pathogens and / or microbial pathogens on the surface coating 100 may be electrically attracted to the dielectric gap G between the nanoantenna 104 and the conductive layer 102 due to the phenomenon of dielectrophoresis (DEP) (e.g., the viral pathogens and / or microbial pathogens may be attracted toward the dielectric gap G and electrically trapped in the dielectric gap G). Figure 3 Depicted are scanning electron microscope (SEM) photographs showing viruses and / or other microbial pathogens attracted to a dielectric gap due to DEP. DEP is a phenomenon in which forces are exerted on dielectric particles (such as viruses and microbial pathogens) when they are subjected to a non-uniform electric field. This force does not require the particles to be charged. All particles exhibit DEP activity in the presence of an electric field. Figure 1A to Figure 1B In the embodiment shown in FIG, an alternating current (AC) source is applied to the nano-antennas 104 and the conductive layer 102 across the dielectric gap G formed by the dielectric layer 101. Thus, when the AC source is applied to the nano-antennas 104 and the conductive layer 102, viruses and / or microbial pathogens are electrically attracted and confined to the dielectric gap G due to the DEP. The method of electrically attracting the viruses and / or microbial pathogens to the dielectric gap G is configured to increase the exposure of the viruses and / or microbial pathogens to UV light that is trapped and enhanced at the dielectric gap G. In this manner, the method of applying the AC source to the nano-antennas 104 and the conductive layer 102 across the dielectric gap G is configured to enable the incident UV light to destroy viruses and / or other microbial pathogens located on portions of the surface coating 100 that would otherwise not be destroyed without the enhanced dose of incident light.

[0053] The configuration (e.g., shape and size) of the nanoantennas 104 can be selected so that each nanoantenna 104 has a single resonance or two or more resonances (e.g., broadband resonances) at the wavelength of the UV light source to be used to sterilize the surface coating 100. At the resonant wavelength, each nanoantenna 104 of the surface coating 100 is configured to spatially confine the incident UV light so that the effective dose of the UV light is increased (i.e., the nanoantennas 104 of the surface coating 100 are configured to effectively increase the local electromagnetic density of the UV light incident on the surface coating 100). Typically, different viruses or other microbial pathogens are susceptible to genetic damage by light of different wavelengths. Therefore, if the wavelength of the incident UV light is selected to destroy the genetic material of a specific virus or other microbial pathogen, the diameter of the nanoantenna 104 (or the average diameter of the Gaussian distribution of diameters) can be selected in such a way that the nanoantenna 104 exhibits resonance at the selected frequency of the incident UV light.

[0054] Figure 4 is a graph depicting the local intensity enhancement factor of the optical surface coating 100 as a function of the diameter of the nano-antenna 104 for incident UV with a frequency ranging from 200 nm to 400 nm. Figure 4 As shown in , a nanoantenna 104 having a diameter of approximately 140 nm exhibits resonance at a wavelength of approximately 295 nm, a nanoantenna 104 having a diameter of approximately 120 nm exhibits resonance at a wavelength of approximately 280 nm, a nanoantenna 104 having a diameter of approximately 100 nm exhibits resonance at a wavelength of approximately 260 nm, a nanoantenna 104 having a diameter of approximately 90 nm exhibits resonance at a wavelength of approximately 250 nm, a nanoantenna 104 having a diameter of approximately 80 nm exhibits resonance at a wavelength of approximately 240 nm, a nanoantenna 104 having a diameter of approximately 70 nm exhibits resonance at a wavelength of approximately 230 nm, and a nanoantenna 104 having a diameter of approximately 60 nm exhibits resonance at a wavelength of approximately 220 nm. As described above, in one or more embodiments, the diameter of the nanoantenna 104 (or the average diameter of a Gaussian distribution diameter) can be selected so that the nanoantenna 104 exhibits resonance at the frequency of the incident UV light. Even though the intensity enhancement factor of a nanoantenna 104 exhibiting resonance for a particular wavelength may be smaller than the intensity enhancement factor of a nanoantenna 104 that is non-resonant at that particular wavelength (e.g., at a wavelength of approximately 250 nm, a nanoantenna 104 with a diameter of approximately 90 nm exhibits a resonant intensity enhancement factor of approximately 130, and a nanoantenna 104 with a diameter of 140 nm exhibits a non-resonant intensity enhancement factor of approximately 225), it may be beneficial to select the diameter of the nanoantenna 104 in such a way that the nanoantenna 104 exhibits resonance because this will result in the highest confinement of UV light at the dielectric gap G.

[0055] In one or more embodiments, the surface coating 100 may include nanoantennas 104 having two or more different configurations (e.g., two or more different shapes and / or two or more different sizes) depending on, for example, the wavelength of the UV light source to be used to sterilize the surface coating 100 and increase the bandwidth of the resonance of the nanoantennas 104. Furthermore, as described above, in one or more embodiments, the diameters of the nanoantennas 104 have a Gaussian distribution. Thus, in one or more embodiments, the nanoantennas 104 exhibit resonance at a variety of different wavelengths. Thus, broadband UV light (e.g., sunlight) may be utilized, rather than UV light having a wavelength that targets a specific virus or other microbial pathogen, because different nanoantennas 104 are configured to exhibit resonance at different wavelengths of incident light.

[0056] Figure 5 The present invention is a manufacturing method according to an embodiment of the present invention. Figure 1A to Figure 1B An embodiment of a surface coating 100 is shown in FIG. 1 and a flow chart of the steps of a method 200 of applying the surface coating 100 to an article or fixture. Figures 6A to 6C is a perspective view of steps in a method 200 of making a surface coating 100 .

[0057] exist Figure 5 and Figure 6A In the embodiment shown in FIG, method 200 includes a step 210 of forming a dielectric layer on a substrate of an article or fixture. In one embodiment, step 210 of forming the dielectric layer includes mixing two polymers 301 and 302 (e.g., polymethyl methacrylate (PMMA) 301 and polystyrene (PS) 302) together in a solution (e.g., a solvent such as cyclohexanone) and applying the mixture to a substrate S of the article or fixture. Step 210 of applying the mixture of polymers 301 and 302 to the substrate S can be performed in any suitable manner, such as by brushing, spraying, dipping, vapor deposition, or printing. Furthermore, during step 210, as described above, the mixture of polymers 301 and 302 can be deposited on the substrate S at any suitable thickness, depending on the desired thickness of the dielectric layer and the desired dielectric gap G between the nanoantenna and the conductive layer. In one or more embodiments, the mixture of polymers 301 and 302 can be deposited on the substrate S at a thickness ranging from about 5 nm to about 15 nm. After the step 210 of depositing the mixture of the two polymers 301 , 302 on the substrate S, the first polymer 301 (for example PMMA) defines a dielectric layer.

[0058] In the illustrated embodiment, PS 302 in the mixture is configured to self-assemble into a series of spots (e.g., disks). In subsequent steps of method 200, PS spots 302 are used to form nano-openings 303 in the dielectric layer. Thus, the configuration (e.g., shape and size) of PS spots 302 defines the configuration (e.g., shape and size) of nano-openings 303 in the dielectric layer and the configuration (e.g., shape and size) of the nano-antennas formed within the nano-openings 303. In one or more embodiments, PS spots 302 have various diameters, with these diameters having a Gaussian distribution around a median diameter. In one or more embodiments, the median diameter of PS spots 302 can be a function of various parameters, including, for example, the deposition rate (e.g., spin coating rate), the relative humidity of the chamber in which the mixture of PMMA 301 and PS 302 is deposited, and the ratio of PS 302 to PMMA 301 in the mixture. Therefore, in one or more embodiments, step 210 of forming the dielectric layer can include controlling these parameters to achieve a desired diameter (or average diameter) for the nano-openings and the nano-antennas formed within the nano-openings. As described above, in one or more embodiments, the diameter (or average diameter) of the nanoantennas can be selected based on the wavelength of the incident UV light that will be used to destroy viruses and / or other microbial pathogens on the surface coating (e.g., step 210 can include controlling the deposition rate, the relative humidity of the deposition chamber, and the ratio of PS to PMMA in the mixture such that the subsequently formed nanoantennas exhibit one or more resonance peaks at the wavelength of the incident UV light).

[0059] exist Figure 5 and Figure 6B In the embodiment shown in , method 200 further includes a step 220 of forming nano-openings 303 (e.g., holes) in the dielectric layer to expose portions of the underlying substrate S. In one embodiment, step 220 of forming nano-openings 303 in the dielectric layer includes selectively developing the PS spots 302 to remove portions of the dielectric layer in contact with the PS spots 302. The step of selectively removing the PS spots 302 can utilize any solvent that has suitable selectivity for the second polymer 302 (e.g., PS) relative to the first polymer 301 (e.g., PMMA). In one or more embodiments, step 220 can include rinsing the deposited PS and PMMA mixture 301, 302 in cyclohexane twice for 60 seconds and then drying the deposited PS and PMMA mixture 301, 302 in a stream of nitrogen (N2) to remove the PS spots 302.

[0060] exist Figure 5 and Figure 6CIn the embodiment shown in FIG, method 200 further includes step 230 of forming a conductive layer 304 on a dielectric layer 301 (e.g., a PMMA layer) and forming a plurality of nanoantennas 305 in the nano-openings 303 formed in step 220. In the embodiment shown, step 230 of forming the conductive layer 304 and the nanoantennas 305 includes conformally depositing a UV plasma material or a combination of UV plasma materials on the dielectric layer 301 and in the nano-openings 303 in the dielectric layer 301. In one or more embodiments, the UV plasma material deposited in step 230 may be a metal (e.g., aluminum (Al), gallium (Ga), indium (In), tin (Sn), thallium (Tl), lead (Pb), bismuth (Bi), and / or magnesium (Mg)) or a metalloid (e.g., germanium (Ge)). In one or more embodiments, the UV plasma material deposited in step 230 may be gallium nitride (GaN) or aluminum nitride (AlN). The step 230 of depositing the UV plasma material can be performed in any suitable manner, such as by electron beam evaporation, radio frequency (RF) sputtering, thermal sputtering, or molecular beam deposition. In one or more embodiments, the process used to deposit the UV plasma material in step 230 can vary depending on the UV plasma material selected (e.g., if aluminum is selected as the UV plasma material, the process utilized in step 230 can be electron beam evaporation, and if gallium nitride is selected as the UV plasma material, the process utilized in step 230 can be molecular beam deposition). After the step 230 of depositing the UV plasma material, UV plasma nanoantennas 305 are formed in the nano-openings 303 of the dielectric layer 301 (e.g., PMMA layer), a UV plasma conductive layer 304 is formed on the dielectric layer 301 (e.g., PMMA layer), and the UV plasma nanoantennas 305 are separated from the UV plasma conductive layer 304 by a dielectric gap G formed by the dielectric layer 301 (e.g., PMMA layer).

[0061] 7A to 7BA surface coating 500 according to one embodiment of the present disclosure is depicted. The surface coating 500 can be applied to a substrate S of any suitable article or fixture that is desired to be sterilized against microbial and viral pathogens (e.g., an air conditioning filtration system, high-touch surfaces such as elevator buttons, door handles, and door pulls, and / or any other surface that may contribute to the spread of pathogens). In the illustrated embodiment, the surface coating 500 includes a conductive layer 501 segmented into an array of nanoantennas 502 and a dielectric pattern 503 in the conductive layer 501. The dielectric pattern 503 separates adjacent nanoantennas 502 from each other (i.e., adjacent nanoantennas 502 of the conductive layer 501 are separated by a dielectric gap G formed by the dielectric pattern 503). In one or more embodiments, the dielectric gap G between adjacent nanoantennas 502 of the conductive layer 501 can be about 10 nm or less (e.g., about 5 nm or less).

[0062] In the illustrated embodiment, the dielectric pattern 503 comprises an array of discrete rectangular window frame patterns 504. In one or more embodiments, the dielectric pattern 503 can comprise an array of other shapes, such as circular, square, triangular, etc. In one or more embodiments, the dielectric pattern 503 can be arranged in any other suitable arrangement or pattern (e.g., grid lines, stripes, V-shaped lines, a sawtooth pattern, or a cross pattern). In one or more embodiments, the dielectric pattern 503 can comprise a series of discrete patterns or a single continuous pattern.

[0063] Conductive layer 501 (and the nanoantennas 502 defined thereby) can be formed of any UV plasma material or combination of UV plasma materials, such as metals (e.g., aluminum (Al), gallium (Ga), indium (In), tin (Sn), thallium (Tl), lead (Pb), bismuth (Bi), and / or magnesium (Mg)) or metalloids (e.g., germanium (Ge)). In one or more embodiments, conductive layer 501 (and the nanoantennas 502 defined thereby) can be formed of gallium nitride (GaN) or aluminum nitride (AlN). Dielectric pattern 503 can be formed of any dielectric material, such as ceramic, glass, or plastic (e.g., polymethyl methacrylate (PMMA)).

[0064] In use, when UV light (e.g., UVC and / or UVB light) is incident on the surface coating 500, coupling between photons in the incident UV light and free electrons on the surface of the nanoantennas 502 (i.e., free electrons in the UV plasma material) flows toward the dielectric gap G defined by the dielectric pattern 503 (i.e., the free electrons flow toward the dielectric interface between adjacent nanoantennas 502). The dielectric gap G between adjacent nanoantennas 502 restricts the flow of free electrons between adjacent nanoantennas 502, which creates an accumulation of electrons at the dielectric gap G. This accumulation of electrons traps the electric field in the dielectric gap G, thereby locally increasing the electromagnetic field strength at the dielectric gap G. Generally, reducing the size of the dielectric gap G between adjacent nanoantennas 502 increases the local enhancement of the electromagnetic field strength at the dielectric gap G. For example, in one or more embodiments, the dielectric gap G between adjacent nanoantennas 502 is configured to locally increase the effective dose of UV light incident on the surface coating 500 by greater than approximately 1,000 times. In one or more embodiments, the dielectric gap G between adjacent nano-antennas 502 is configured to locally increase the effective dose of UV light incident on the surface coating 500 by a factor ranging from about 500 to about 1,500 or more.

[0065] Additionally, in one or more embodiments, due to the phenomenon of dielectrophoresis (DEP), viral pathogens and / or microbial pathogens on the surface coating 500 may be electrically attracted to the dielectric gap G between adjacent nanoantennas 502 of the conductive layer 501 (e.g., viral pathogens and / or microbial pathogens may be attracted toward the dielectric gap G and electrically trapped in the dielectric gap G). 7A to 7B In the embodiment shown in FIG, an alternating current (AC) source is applied to the nano-antenna 502 across the dielectric gap G formed by the dielectric pattern 503. Thus, when the AC source is applied to the nano-antenna 502 across the dielectric gap G, viruses and / or microbial pathogens are electrically attracted and confined to the dielectric gap G due to the DEP. The method of electrically attracting the viruses and / or microbial pathogens to the dielectric gap G is configured to increase the exposure of the viruses and / or microbial pathogens to UV light that is trapped and enhanced at the dielectric gap G. In this manner, the method of applying the AC source to the nano-antenna 502 across the dielectric gap G is configured to enable the incident UV light to destroy viruses and / or other microbial pathogens located on portions of the surface coating 500 that would otherwise not be destroyed without the enhanced dose of incident light.

[0066] The configuration (e.g., shape and size) of the nanoantennas 502 can be selected so that each nanoantenna 502 has a single resonance or two or more resonances (e.g., broadband resonances) at the wavelength of the UV light source to be used to sterilize the surface coating 500. In one or more embodiments, the width of the nanoantennas 502 can be in the range of from about 20 nm to about 500 nm. At the resonant wavelength, each nanoantenna 502 of the surface coating 500 is configured to spatially confine the incident UV light so as to increase the effective dose of the UV light (i.e., the nanoantennas 502 of the surface coating 500 are configured so that the local electromagnetic density of the UV light incident on the surface coating 500 is effectively increased). Typically, different viruses or other microbial pathogens are susceptible to genetic damage by light of different wavelengths. Therefore, if the wavelength of the incident UV light is selected to destroy the genetic material of a specific virus or other microbial pathogen, the width of the nanoantenna 502 can be selected in a manner that causes the nanoantenna 502 to exhibit resonance at the selected frequency of the incident UV light.

[0067] Figure 8 The present invention is a manufacturing method according to an embodiment of the present invention. 7A to 7B Flowchart of the steps of a method 600 of an embodiment of a surface coating 500 is shown in FIG. Figures 9A to 9E It is shown in Figure 8 A side view of surface coating 500 during method 600 is shown in FIG.

[0068] exist Figure 8 and Figure 9AIn the embodiment shown in FIG, method 600 includes a step 610 of depositing a UV plasma material or a combination of UV plasma materials on a substrate S. During step 610, the UV plasma material forms a series of first protrusions 701 on the substrate S that are laterally spaced apart by a distance D. In one or more embodiments, the UV plasma material deposited in step 610 can be a metal (e.g., aluminum (Al), gallium (Ga), indium (In), tin (Sn), thallium (Tl), lead (Pb), bismuth (Bi), and / or magnesium (Mg)) or a metalloid (e.g., germanium (Ge)). In one or more embodiments, the UV plasma material deposited in step 610 can be gallium nitride (GaN) or aluminum nitride (AlN). Step 610 of depositing the UV plasma material can be performed in any suitable manner, such as by electron beam evaporation, radio frequency (RF) sputtering, thermal sputtering, or molecular beam deposition. In one or more embodiments, the process used to deposit the UV plasma material in step 610 can vary depending on the UV plasma material selected (e.g., if aluminum is selected as the UV plasma material, the process utilized in step 610 can be electron beam evaporation, and if gallium nitride is selected as the UV plasma material, the process utilized in step 610 can be molecular beam deposition). In step 610, the UV plasma material can be deposited by any suitable process or processes, such as electron beam evaporation, dipping, spraying, spin coating, and / or printing. In step 610, nanoantennas (such as a series of pillars, rods, and / or ribs) can be formed in any suitable configuration (e.g., shape, size, and arrangement). Additionally, in step 610, the spaces between adjacent protrusions 701 can be formed using a mask and a photoresist (e.g., a positive or negative photoresist). In one or more embodiments, the distance D between adjacent protrusions 701, in addition to being equal to or substantially equal to twice the width of each dielectric gap between the nanoantennas, can also be equal to or substantially equal to the desired width of each nanoantenna.

[0069] In the illustrated embodiment, method 600 further includes step 620 of conformally depositing a dielectric material 702 on the series of first protrusions 701 formed in step 610 and on the substrate S in the spaces between adjacent protrusions 701. The dielectric material 702 deposited in step 620 can be any suitable dielectric material, such as ceramic, glass, or plastic (e.g., polymethyl methacrylate (PMMA)). In step 620, dielectric material 702 can be deposited using any suitable process or processes, such as atomic layer deposition (ALD), electron beam evaporation, dipping, spraying, coating, brushing, or printing. In step 620, dielectric material 702 can be deposited to any suitable thickness, such as approximately 10 nm or less (or 5 nm or less), depending on the desired dielectric gap G between adjacent nanoantennas.

[0070] Now refer to Figure 8 and Figure 9B In the embodiment shown in FIG6 , the method 600 further includes a step 630 of conformally depositing a UV plasma material on the dielectric material 702 deposited in step 620. The UV plasma material deposited in step 630 forms a series of second protrusions 703 on portions of the dielectric material 702 located in spaces between the series of first protrusions 701 and forms a series of redundant protrusions 704 on portions of the dielectric material 702 located on the series of first protrusions 701. The UV plasma material deposited in step 630 may be the same as the UV plasma material deposited in step 610 (e.g., aluminum (Al), gallium (Ga), indium (In), tin (Sn), thallium (Tl), lead (Pb), bismuth (Bi) and / or magnesium (Mg), germanium (Ge), gallium nitride (GaN), and / or aluminum nitride (AlN)), and the UV plasma material deposited in step 630 may be deposited in the same manner as the UV plasma material deposited in step 610 (e.g., electron beam evaporation or molecular beam deposition).

[0071] Now refer to Figure 8 and Figure 9C , method 600 further includes step 640 of applying adhesive 705 to excess protrusion 704. Adhesive 705 may be any suitable type or kind of adhesive configured to bond to the UV plasma material deposited in step 630.

[0072] Now refer to Figure 8 and Figure 9D , method 600 further includes step 650 of stripping adhesive 705 and excess protrusion 704 adhered to adhesive 705. After step 650, excess protrusion 704 is removed or substantially removed to expose the portion of dielectric material 702 located on first protrusion 701. In one or more embodiments, excess protrusion 704 can be removed in any other suitable manner, such as by etching.

[0073] Now refer to Figure 8 and Figure 9E In the embodiment shown in FIG, method 600 further includes a step 660 of selectively removing portions of dielectric material 702 located on the upper surfaces of the series of first protrusions 701. Step 660 of selectively removing portions of dielectric material 702 located on the first protrusions 701 can utilize any suitable solvent, such as a solvent having high selectivity for dielectric material 702 relative to the UV plasma material of the first protrusions 701 and the second protrusions 703.

[0074] The first protrusions 701 formed by depositing the UV plasma material in step 610 and the second protrusions 703 formed by depositing the UV plasma material in step 630 together define the nano-antennas 502 of the conductive layer 501, and the portion of the dielectric material 702 remaining after step 660 defines the dielectric pattern 503 and the dielectric gap G between adjacent nano-antennas 502, as shown in FIG. 7A to 7B The embodiment of the surface coating 500 is shown in FIG.

[0075] Figure 10 A sterilization system 800 according to one embodiment of the present disclosure is depicted, comprising a surface coating 900 applied to an article or fixture and at least one UV light source 1000. The surface coating 900 may be applied to an article or fixture. Figure 1A to Figure 1B The embodiment of the surface coating 100 shown in and / or 7A to 7B . The surface coating 900 can be applied to any suitable article or fixture that is desired to be sterilized against microbial and viral pathogens (e.g., air conditioning filtration systems, high-contact surfaces such as elevator buttons, door handles, and door pulls, and / or any other surface that may contribute to the spread of pathogens). In one or more embodiments, the UV light source 1000 is constructed (e.g., positioned and oriented) to irradiate the surface coating 900 with UV light (e.g., UVB and / or UVC light). In the embodiment shown, the UV light emitted from the UV light source 1000 can have a dose that is safe for human exposure (e.g., having a dose of about 3 mJ / cm 2 or less UVC light). As described above, the surface-coated nanoantennas (e.g., Figure 1A to Figure 1B The nanoantenna 104 of the surface coating 100 shown in FIG. 7A to 7BThe nanoantennas 502 of the surface coating 500 shown in FIG. 5 are configured to locally increase the electromagnetic field intensity at the dielectric gap G from a dose safe for human exposure to a level sufficient to kill genetic material in viruses and / or other microbial pathogens on the surface coating 900 (e.g., locally increasing the electromagnetic field density at the dielectric gap G by a factor of approximately 1,000 or greater). Furthermore, in one or more embodiments, the sterilization system 800 may include a power supply 1100 configured to supply alternating current (AC) across the dielectric gap G in the surface coating 900. The method of applying AC across the dielectric gap G is configured to attract and confine viruses and / or other microbial pathogens to the surface coating 900 in the dielectric gap G due to a phenomenon called dielectrophoresis (DEP). The method of attracting and confining viruses and / or other microbial pathogens in the dielectric gap G is configured to enable UV light emitted from one or more UV light sources 1000 to destroy viruses and / or other microbial pathogens located on portions of the surface coating 900 that would otherwise not be destroyed without the increased dose of incident light (or without sufficient increased dose of incident light).

[0076] Although the present invention has been described in detail with particular reference to exemplary embodiments thereof, the exemplary embodiments described herein are not intended to be exhaustive or to limit the scope of the invention to the precise forms disclosed. Those skilled in the art will appreciate that changes and variations in the described structures, as well as in the assembly and method of operation, may be practiced without significantly departing from the principles, spirit, and scope of the invention as set forth in the appended claims.

Claims

1. A surface coating configured to locally enhance the ultraviolet light density of ultraviolet light incident on the surface coating, the surface coating comprising: dielectric layer; a conductive layer disposed on the dielectric layer; a plurality of nano-openings in the dielectric layer and the conductive layer; a plurality of nano-antennas located in the plurality of nano-openings; as well as A plurality of dielectric gaps are located between the plurality of nano-antennas and the conductive layer, The conductive layer and the plurality of nano-antennas both comprise ultraviolet plasma materials, and the conductive layer and the plurality of nano-antennas are configured to be applied with an alternating current source across the plurality of dielectric gaps.

2. The surface coating according to claim 1, wherein Each of the plurality of dielectric gaps has a distance of 10 nm or less.

3. The surface coating according to claim 1, wherein The ultraviolet plasma material is selected from the group consisting of aluminum, gallium, indium, tin, thallium, lead, bismuth, magnesium, germanium, gallium nitride, aluminum nitride, and combinations thereof.

4. The surface coating according to claim 1, wherein The dielectric layer includes polymethyl methacrylate.

5. The surface coating according to claim 1, wherein Each of the plurality of nanoantennas has a shape selected from the group consisting of a circle, an ellipse, a square, a rectangle, and a cone.

6. The surface coating according to claim 5, wherein An average diameter of the plurality of nanoantennas is in a range from 20 nm to 500 nm.

7. The surface coating according to any one of claims 1 to 6, wherein At least one nano-antenna among the plurality of nano-antennas has a shape or size different from a shape or size of another nano-antenna among the plurality of nano-antennas.

8. The surface coating according to any one of claims 1 to 6, wherein The periodicity of the array of the plurality of nanoantennas is in the range from 50 nm to 1,000 nm.

9. The surface coating according to any one of claims 1 to 6, wherein The plurality of nano-openings and the plurality of nano-antennas are arranged to cover at least 60% of the surface coating.

10. A surface coating configured to locally enhance ultraviolet light density, the surface coating comprising: a layer of ultraviolet plasmonic material comprising a plurality of nanoantennas; as well as a dielectric pattern located in the layer of ultraviolet plasma material, wherein the dielectric pattern separates adjacent nanoantennas in the plurality of nanoantennas from each other by dielectric gaps; Therein, adjacent nanoantennas are configured to be applied with an AC source across a dielectric gap.

11. The surface coating according to claim 10, wherein The dielectric gap has a distance of 10 nm or less.

12. The surface coating according to claim 10, wherein The ultraviolet plasma material is selected from the group consisting of aluminum, gallium, indium, tin, thallium, lead, bismuth, magnesium, germanium, gallium nitride, aluminum nitride, and combinations thereof.

13. The surface coating according to claim 10, wherein The dielectric pattern has a pattern selected from the group consisting of an array of shapes including grid lines, stripes, V-shaped lines, a sawtooth pattern, a cross pattern, and combinations thereof.

14. The surface coating according to claim 10, wherein An average width of the plurality of nanoantennas is in a range from 20 nm to 500 nm.

15. A method for producing a surface coating according to claim 1, comprising the steps of: depositing a mixture of a first polymer and a second polymer on a substrate, the second polymer self-arranging into a plurality of spots; selectively removing the plurality of spots to form the plurality of nano-openings in the dielectric layer formed of the first polymer; as well as An ultraviolet plasma material is deposited on the dielectric layer and in the plurality of nano-openings, the ultraviolet plasma material forming the plurality of nano-antennas in the plurality of nano-openings and forming a conductive layer on the dielectric layer.

16. The method according to claim 15, wherein The step of depositing the mixture comprises a process selected from the group consisting of brushing, spraying, dipping, vapor deposition and printing.

17. The method according to claim 15, wherein: The step of depositing the ultraviolet plasma material includes electron beam evaporation or molecular beam deposition of the ultraviolet plasma material.

18. The method according to claim 15, wherein The first polymer includes polymethyl methacrylate, and the second polymer includes polystyrene.

19. A method for producing a surface coating according to claim 10, comprising the steps of: depositing an ultraviolet plasma material on a substrate to form a plurality of first protrusions on the substrate, the plurality of first protrusions being spaced apart from each other by spaces; depositing a dielectric material on the plurality of first protrusions and in spaces between the plurality of first protrusions; depositing the ultraviolet plasma material to form a plurality of second protrusions in spaces between the plurality of first protrusions and a plurality of redundant protrusions on the plurality of first protrusions; removing the plurality of redundant protrusions; as well as selectively removing portions of the dielectric material located on the plurality of first protrusions, wherein the plurality of first protrusions and the plurality of second protrusions define the plurality of nanoantennas of the layer of ultraviolet plasma material, and The remaining portion of the dielectric material defines a dielectric pattern.

20. The method according to claim 19, wherein The step of removing the plurality of excess protrusions includes applying an adhesive on the plurality of excess protrusions and peeling off the adhesive and the plurality of excess protrusions adhered to the adhesive.

21. A method for sterilizing a surface coating according to claim 1 or 10, the method comprising: irradiating the surface coating with ultraviolet light from an ultraviolet light source, the ultraviolet light having a first dose that is safe for human exposure, During irradiation of the surface coating with the ultraviolet light, the dielectric gap locally increases a first dose of the ultraviolet light to a second dose that is higher than the first dose, and the second dose is unsafe for human exposure.

22. The method according to claim 21, wherein The second dose is at least 1,000 times greater than the first dose.

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