Articles comprising nanostructured surfaces and surrounding voids, methods for manufacturing the same, and optical elements

Abstract

The present disclosure provides an article including a layer having a nanostructured first surface including nanofeatures and an opposing second surface; and an inorganic layer including a major surface bonded to a portion of the nanostructured first surface. The nanostructured first surface includes convex and / or concave features formed from a single composition. The article includes at least one enclosed void partially defined by the nanostructured first surface. The present disclosure also provides a method of manufacturing the article, the method including treating a major surface of the inorganic layer with a coupling agent, contacting the nanostructured surface of the layer with the treated inorganic layer, and securing the two layers together via the bonding coupling agent by bonding at least one of the nanostructured surface or the treated inorganic layer. Additionally, the present disclosure provides an optical element including the article. The nanostructured surface of the article is protected from damage and contamination by the inorganic layer.

Description

[Technical Field]

[0001] This disclosure generally relates to articles containing nanostructured surfaces and methods for manufacturing such articles. [Background technology]

[0002] Nanostructured surfaces can provide useful optical effects for various applications, such as improving the color and efficiency of devices. For nanostructured surfaces to provide the desired optical functionality, a refractive index difference or contrast is required at the nanostructured interface. While nanostructured surfaces can be exposed to the surrounding environment to provide refractive index contrast, exposed surfaces limit the adhesion of the nanostructured surface to other surfaces and are susceptible to environmental damage and / or contamination. Therefore, improvements in the protection of nanostructured surfaces remain necessary. [Overview of the project]

[0003] In a first embodiment, an article is provided. The article includes a first layer having a nanostructured first surface containing nanofeatures and a second surface on the opposite side, and b) a second layer having a first main surface and a second main surface on the opposite side, wherein the first main surface is bonded to a portion of the nanostructured first surface of the first layer, and the second layer comprises an inorganic material. The nanostructured first surface includes concave features, convex features formed of a single composition, or both concave and convex features. The article includes at least one enclosed void partially defined by the nanostructured first surface of the first layer.

[0004] In a second embodiment, an optical element is provided which includes an article according to the first embodiment.

[0005] A third embodiment provides a method for manufacturing an article. The method includes: a) obtaining a first layer comprising a nanostructured first surface containing nanofeatures and a second surface on the opposite side; b) treating a first main surface of the second layer with a coupling agent to bond the coupling agent to the second layer, wherein the first main surface of the second layer contains an inorganic material; c) bringing the treated first main surface of the second layer into contact with a portion of the nanostructured first surface of the first layer; and d) bonding the first layer and the second layer together via a coupling agent by bonding at least one of the first layer or the coupling agent bonded to the second layer. The coupling agent either directly bonds the first main surface of the second layer to the nanostructured first surface of the first layer, or exists as part of a coupling agent layer. The nanostructured first surface includes concave features, convex features formed from a single composition, or both concave and convex features. The nanofeatures of the first layer and the first main surface of the second layer cooperate to define at least one void.

[0006] Articles and methods according to at least specific embodiments of the present disclosure provide enclosed nanostructured surfaces that protect the nanostructured surface and maintain refractive index contrast at the air interface.

[0007] The above summary of this disclosure is not intended to describe each of the disclosed embodiments or all implementations of this disclosure. The following description provides more specific examples of exemplary embodiments. While guidance is provided in several places throughout this application by listing examples, these examples can be used in various combinations. In each example, the listed enumerations serve only as representative groups and should not be interpreted as exclusive enumerations. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view of an exemplary article according to this application. [Figure 2A]This is a scanning electron microscope (SEM) image of a cross-section of an exemplary article of Example 1 according to this application, at a magnification of 2,000x. [Figure 2B] Figure 2A is an SEM image of a cross-section of an exemplary article at a magnification of 20,000x. [Figure 2C] Figure 2A is an SEM image of a cross-section of an exemplary article at a magnification of 50,000x. [Figure 3A] This is an SEM image of a cross-section of the first nanostructured region of an exemplary article of Example 2 according to this application, at a magnification of 2,000x. [Figure 3B] Figure 3A is an SEM image of a cross-section of an exemplary article at a magnification of 10,000x. [Figure 3C] Figure 3A is an SEM image of a cross-section of an exemplary article at a magnification of 100,000x. [Figure 3D] This is an SEM image of a cross-section of the second nanostructured region of an exemplary article of Example 2 at a magnification of 100,000x. [Figure 4A] This is a schematic cross-sectional view of an exemplary article according to Example 2. [Figure 4B] This is a photograph of an exemplary item used in Example 2. [Figure 5] This is a flowchart illustrating an exemplary method for manufacturing an article according to this application.

[0009] The figures identified above illustrate some embodiments of this disclosure, but other embodiments are also intended as referred to herein. The figures are not necessarily drawn to scale. In all cases, this disclosure presents the invention by presenting representative examples rather than limitations. It should be understood that numerous other modifications and embodiments may be devised by those skilled in the art and that they fall within the scope and spirit of the principles of the invention. [Modes for carrying out the invention]

[0010] Glossary As used herein, the term "adjacent" refers to a material or layer that can be in contact (i.e., directly adjacent) with another material or layer, or can be separated from another material or layer by an intervening material, layer, or gap.

[0011] The phrases "in planar contact" or "contacting planar-wise" are used to indicate that one layer or layered structure is in contact with another layer or layered structure (and is disposed either above or below). Such contact is contact by a surface rather than by an edge.

[0012] As used herein, the term "organic layer" refers to a layer that predominantly (e.g., more than about 50 weight percent) comprises one or more materials that include hydrocarbon compounds or their halogenated analogs, a three-dimensionally continuous polymer matrix, or both.

[0013] As used herein, the term "inorganic layer" refers to a layer that predominantly (e.g., more than about 50 weight percent) comprises one or more materials that lack compounds having carbon-hydrogen bonds or their halogenated analogs.

[0014] As used herein, "nanostructured" refers to a surface that includes a topography in the form of nanofeatures having a designed pattern, where the nanofeatures include the material that defines the surface and where at least one of the height of the nanofeatures or the width of the nanofeatures is less than about 1 micron (i.e., 1 micrometer, or 1000 nanometers) and greater than 10 nanometers.

[0015] As used herein, "index of refraction" refers to the index of refraction of a material for perpendicularly incident 633 nm light in the plane of the material, unless otherwise specified.

[0016] As used herein, "gas" refers to any material that is in the gas phase at standard temperature and standard pressure (i.e., 0 degrees Celsius and 10 5 pascals).

[0017] As used herein, "birefringence" means refractive indices in orthogonal x, y, and z directions, which are not all the same. The refractive indices are denoted as n x , n y , and n z respectively. In the layers described herein, the axes are selected such that the x and y axes are in the plane of the layer and the z axis is perpendicular to the plane of the layer, typically corresponding to the thickness or height of the layer. When the refractive index in one in-plane direction is greater than the refractive index in another in-plane direction, the x axis is generally selected to be the in-plane direction having the maximum refractive index.

[0018] As used herein, "transparent to visible light" means that the level of transmittance of an unpatterned substrate or article is 60 percent or more, 70 percent or more, 80 percent or more, 90 percent or more, 95 percent or more, or 98 percent or more, for at least one polarization state of visible light, and the percent transmittance is optionally polarized and normalized with respect to the intensity of the incident light. The term "visible" associated with "transparent to visible light" modifies the term "light" to specify the wavelength range of light for which the article is transparent.

[0019] The terms "preferred" and "preferably" refer to embodiments of the present disclosure that can provide certain benefits under certain circumstances; however, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments is not intended to suggest that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the present disclosure.

[0020] In this application, terms such as “a,” “an,” and “the” are not intended to refer only to singular entities, but include general classifications, and specific examples thereof may be used for illustrative purposes. The terms “a,” “an,” and “the” are used interchangeably with the term “at least one.” The phrases “at least one of” and “including at least one of” following an enumeration refer to any one item in the enumeration, or any combination of two or more items in the enumeration.

[0021] As used herein, the term "or" is used in its ordinary sense, generally including "and / or," unless otherwise specified. The term "and / or" means one or all of the enumerated elements, or any combination of two or more of the enumerated elements.

[0022] Furthermore, in this specification, all numbers are assumed to be modified with the term “approximately,” and preferably with the term “exactly.” When used herein, in relation to a measured quantity, the term “approximately” refers to the variation in the measured quantity that can be predicted by a person skilled in the art who performs the measurement and exercises a level of care commensurate with the purpose of the measurement and the precision of the measuring instrument used. Moreover, in this specification, the description of a numerical range by endpoints includes all numbers and their endpoints that are contained within that range (for example, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0023] When used herein as a modifier for a characteristic or attribute, the term “generally” means, unless otherwise specified, that the characteristic or attribute is readily recognizable to a person skilled in the art, but does not require absolute precision or perfect agreement (e.g., within ±20% for quantifiable characteristics). The term “substantially” means, unless otherwise specified, a high degree of approximation (e.g., within ±10% for quantifiable characteristics), but again, does not require absolute precision or perfect agreement. Terms such as identical, equal, uniform, constant, and strictly are understood to mean that they do not require absolute precision or perfect agreement, but are within the normal tolerance or measurement error applicable to the particular situation.

[0024] Goods In the first aspect, an article is provided. The article is, a) A first layer comprising a nanostructured first surface containing nanofeatures and a second surface on the opposite side, wherein the nanostructured first surface contains concave features, convex features formed from a single composition, or both concave and convex features, b) A second layer comprising a first main surface and a second main surface on the opposite side, wherein the first main surface is bonded to a portion of the nanostructured first surface of the first layer, the article comprising at least one enclosed void partially defined by the nanostructured first surface of the first layer, and the second layer comprising an inorganic material.

[0025] It has been discovered that nanostructured surfaces can be used to form articles containing one or more voids and exhibiting refractive index differences, which are protected from damage or contamination.

[0026] Figure 1 is a schematic cross-sectional view of an exemplary article 1000 according to this application. Article 1000 includes a first layer 110 including a nanostructured first surface 112 containing a nanofeature 114 and a second surface 116 on the opposite side, and a second layer 120 including a first main surface 122 bonded to a portion of the nanostructured first surface 112 (in this case, bonded to a portion of the nanofeature 114), wherein the second layer 120 is an inorganic layer. The nanostructured first surface includes concave features, convex features formed from a single composition, or both concave and convex features. "Single composition" means that the convex feature is manufactured from the same material throughout the convex feature, rather than including a portion of the feature having a different composition from another part of the same feature. In some embodiments, the convex feature has the same composition as the first layer 110 (e.g., its bulk). In some embodiments, the concave feature is defined by a structure formed from a single composition (e.g., the first layer). In some embodiments, the composition may be, for example, a polymer, a polymer blend, and / or a polymer matrix containing nanoparticles dispersed in the polymer matrix. An advantage of a convex feature consisting of a single composition is that the convex feature can often be formed by a relatively simple nanoreplication method, as described in the following examples with respect to film A, for example.

[0027] In this embodiment, the nanofeatures 114 of the first layer 110 and the first main surface 122 of the second layer 120 cooperate to define at least one void 130 (for example, in the form of a negative space between the first layer 110 and the second layer 120). The enclosed void 130 is not filled with a solid or liquid, but rather contains a vacuum or gas. Suitable gases include, for example, ambient air (e.g., natural atmosphere), gas, or a gas blend (e.g., 90% nitrogen and 10% oxygen). In some embodiments, the suitable gas may include at least one inert gas (e.g., nitrogen, argon, helium, xenon, etc.). In the embodiment shown in Figure 1, the nanostructured first surface 112 includes both concave features 117 and convex features 119. Alternatively, the article may include only one of the concave features 117 or the convex features 119. The advantage of using only concave features is that the second layer can contact the main surface of the first layer rather than the tops of numerous convex features, and the resulting article may be more fragile than an article with convex features. The embodiment shown in Figure 1 includes both individual voids 130 provided within the concave features 117 and a larger connecting void 130 extending around a plurality of convex features 119.

[0028] Figures 2A to 2C show three magnification SEM images of article 1000 manufactured according to the following Example 1. Referring to Figure 2A (i.e., 2,000x magnification), article 1000 includes a first layer 110 containing a plurality of nanofeatures 114, and a second layer 120 attached to a portion of the nanostructured surface of the first layer 110 (i.e., attached to a portion of the nanofeatures 114). The first layer 110 has a thickness of about 8 micrometers. Article 1000 further includes a third layer 140 attached to a second surface 116 opposite to the first layer 110. The third layer 140 contains glycol-modified polyethylene terephthalate (PETg) and has a thickness of about 15 micrometers. Referring to Figure 2B (i.e., at 20,000x magnification), we see the first layer 110, the nanostructured first surface 112 containing the nanofeatures 114, the second layer 120, and the coupling agent layer 111 attached to a portion of the nanofeatures 114. In the embodiment of Figure 2B, there is a single connected void 130 surrounding many, almost all, or all of the (e.g., convex) nanofeatures 114. Referring to Figure 2C (i.e., at 50,000x magnification), some of the shapes of the nanofeatures 114 are more clearly visible.

[0029] Optionally, the second layer 120 may be substantially planar. As used herein, “substantially planar” with respect to a layer means that the surface of the layer does not essentially contain recesses and / or protrusions extending above and / or below the plane of the layer, the recesses and / or protrusions having a depth or height of 100 micrometers, 90 micrometers, 80 micrometers, 70 micrometers, 60 micrometers, 50 micrometers, 40 micrometers, 30 micrometers, 25 micrometers, 20 micrometers, 15 micrometers, 10 micrometers, 9 micrometers, 8 micrometers, 7 micrometers, 6 micrometers, 5 micrometers, 4 micrometers, 3 micrometers, more than 2 micrometers, or more than 1 micrometer. Typically, the recesses and / or protrusions have a depth or height of less than 1 millimeter, for example, 900 micrometers or less, 800 micrometers, 700 micrometers, 600 micrometers, 500 micrometers, 400 micrometers, or 300 micrometers or less. The depth or height of recesses or protrusions on the layer surface can be measured using a confocal microscope.

[0030] In some embodiments, the first layer is an organic layer, such as a polymer layer. The first layer 110 may include a crosslinking material or a crosslinkable material. The first layer 110 may have a refractive index in the range of, for example, 1.2 to 2.2, or 1.4 to 1.75. Unless otherwise specified or the context clearly indicates otherwise, the refractive index refers to the refractive index measured at 632 nm. In some embodiments, the first layer 110 has refractive indices of 1.3 or greater, 1.5 or greater, 1.6 or greater, 1.7 or greater, or 1.75 or greater, and 2.2 or less, 2.1 or less, or 2.0 or less. Article 1000 provides a refractive index contrast (the absolute difference between the refractive index of the first layer 110 and the refractive index of the void 130). In some embodiments, the refractive index contrast is in the range of 0.1 to 1.0, 0.3 to 1.0, or 0.5 to 1.0.

[0031] A nanostructure is a structure having at least one dimension, such as a width or height of less than 1 micrometer and 10 nanometers or more, and in addition, having a designed shape and pattern (for example, having an intentional design instead of being a result of naturally occurring nanoscale roughness of the material). Nanostructured surfaces can be manufactured using tools having nanostructured surfaces. In some embodiments, the tool includes a plurality of particles partially embedded in a substrate. Useful techniques for manufacturing tools are described in U.S. Patent Application Publication 2014 / 0193612 (Yu et al.) and U.S. Patent No. 8,460,568 (David et al.). The nanostructured surface of the tool can be identified by atomic force microscopy (AFM). Further details on useful nanostructured surfaces and methods for manufacturing nanostructured surfaces can be found as described in International Publication 2009 / 002637(A2) (Zhang et al.) and International Publication 2017 / 205174 (Freier et al.). Referring to Figure 2C, an SEM of the first layer 110 is shown. The first layer 110 includes a nanostructured first surface 112 containing nanofeatures 114.

[0032] Examples of nanofeature properties include pitch, height, depth, aspect ratio, diameter, sidewall angle, and shape. Pitch refers to the distance between adjacent nanofeatures, typically measured from the center of their uppermost parts for convex nanofeatures, or from the center of their lowermost parts for concave nanofeatures. Height refers to the height of convex nanofeatures, measured from their base (where they contact the underlying layer) to their uppermost part. Depth refers to the depth of concave nanofeatures, measured from their uppermost part (the opening in the main surface of the layer) to their deepest part. Aspect ratio refers to the ratio of the cross-sectional width (widest part) to the height or depth of a nanofeature. Diameter refers to the longest line that can be drawn across a nanofeature, from one surface, through the center point, to the opposite surface, at a point along the height or depth of the nanofeature. Sidewall angle refers to the minimum angle formed between the sidewall of a nanofeature and the main surface of the layer in which the nanofeature protrudes or concaves. Sidewall angles can vary at various points along the height or depth of a nanofeature. The shape refers to the cross-sectional shape of the nanofeature. Optionally, the cross-sectional shape (and diameter) may differ at various points along the height or depth of the nanofeature.

[0033] As shown in Figure 1, in certain embodiments, the nanostructured first surface 112 of the first layer 110 includes nanofeatures 114 having regular heights H, while in other embodiments, the nanostructured first surface 112 of the first layer 110 includes nanofeatures 114 having varying heights. This may depend on the method of forming the nanostructured surface. Referring again to Figure 1, at least one dimension of the nanofeature 114, either height H or width W, is less than 1 micrometer, providing the small-sized features required. In some embodiments, the (e.g., average) height H of the nanofeature 114 is less than 1 micrometer, 950 nanometers (nm) or less, 900 nm or less, 850 nm or less, 800 nm or less, 750 nm or less, 700 nm or less, 650 nm or less, or 600 nm or less, and the height H of the nanofeature 114 is 10 nm or more, 15 nm or more, 20 nm or more, 30 nm or more, 50 nm or more, 75 nm or more, 100 nm or more, 150 nm or more, 200 nm or more, 250 nm or more, 300 nm or more, 350 nm or more, 400 nm or more, 450 nm or more, or 500 nm or more. In some embodiments, the (e.g., average) width W of the nanofeature 114 is less than 1 micrometer, 950 nanometers (nm) or less, 900 nm or less, 850 nm or less, 800 nm or less, 750 nm or less, 700 nm or less, 650 nm or less, or 600 nm or less, and the width W of the nanofeature 114 is 10 nm or more, 15 nm or more, 20 nm or more, 30 nm or more, 50 nm or more, 75 nm or more, 100 nm or more, 150 nm or more, 200 nm or more, 250 nm or more, 300 nm or more, 350 nm or more, 400 nm or more, 450 nm or more, or 500 nm or more.

[0034] Each nanostructured surface may comprise nanofeatures such as, for example, nanocolumns or continuous nanowalls containing nanocolumns. Referring to Figures 1 and 2C, respectively, in certain embodiments, a nanofeature 114 includes at least one nonlinear surface 115 in at least one direction. For example, some of the nanofeatures 114 shown in Figure 1 have a curved surface 115 (e.g., on the underside of a concave feature 114), and at least some of the nanofeatures 114 shown in Figure 2C have a curved surface 115 (e.g., on the sidewall of a convex feature 114). Any shape conveniently formed by the nanoreplication process may be employed for the nanofeatures 114 (e.g., prisms, ridges, linear and / or curved polygons). As used herein, “nanoreplication” refers to the process of forming one nanostructured surface from another nanostructured surface, for example, using a curable or thermoplastic material. Nano-replication is further described, for example, in "Micro / Nano Replication," Shinill Kang, John Wiley & Sons, Inc., 2012, Chapters 1 and 5-6. Nano-features optionally have steeply sloping sidewalls that are substantially perpendicular to the second surface opposite the first or second layer. Certain individual nano-features may be equally spaced in one direction along the nanostructured first surface, but not in an orthogonal direction. In some embodiments, certain individual nano-features are equally spaced along the nanostructured first surface in at least two directions. Certain individual nano-features may not be equally spaced in either direction along the nanostructured first surface or in an orthogonal direction.

[0035] As described above, the second layer 120 includes an inorganic material. Suitable inorganic materials are not limited to silicon oxide, but may include metallic or nonmetallic oxides, nitrides, carbides, or borides, or combinations thereof. In some embodiments, the inorganic material includes oxides of titanium, indium, tin, tantalum, zirconium, niobium, aluminum, silicon, or combinations thereof. For example, suitable oxides include silica, aluminum oxide such as alumina, titanium oxide such as titania, indium oxide, tin oxide, indium tin oxide (ITO), hafnium oxide, tantalum oxide, zirconium oxide, niobium oxide, and combinations thereof. In some embodiments, the inorganic material includes glass.

[0036] In some embodiments, the inorganic material exists in the form of a self-supporting layer. In some embodiments, the inorganic material is in the form of a non-self-supporting coating or layer, and the second layer includes the inorganic material supported on a polymer material. For example, the inorganic material may be deposited on a polymer material using sputter deposition, reactive sputtering, chemical vapor deposition (CVD), physical vapor deposition, atomic layer deposition (ALD), vapor deposition, plasma deposition, or plasma-enhanced vapor deposition, plasma-enhanced CVD, plasma-enhanced ALD, or any combination thereof. In some embodiments, the inorganic material may be coated on a polymer material using liquid coating techniques. This includes a liquid containing inorganic particles or reactive precursors that can form an inorganic material such as a sol-gel precursor, or a hybrid inorganic / organic material. In any embodiment, the second layer has an average thickness greater than 1 nm, for example, 2 nm or more, 3 nm or more, 5 nm or more, 7 nm or more, 10 nm or more, 15 nm or more, 20 nm or more, 25 nm or more, 30 nm or more, 35 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, 75 nm or more, 100 nm or more, 200 nm or more, 300 nm or more, 400 nm or more, 500 nm or more, 700 nm or more, 900 nm or more, 1 micrometer or more, 1.25 micrometers or more, 1.5 micrometers or more, 1.75 micrometers or more, 2 micrometers or more, 2.25 micrometers or more, 2.5 micrometers or more, 2.75 micrometers or more, or 3 micrometers or more, and an average thickness of 1 mm or less, 0.75 mm or less, 0.5 mm or less, 0.25 mm or less, 0.1 mm or less, 0.05 mm or less, or 0.01 mm or less. In the selected embodiment, the second layer is non-porous.

[0037] Typically, a coupling agent comprises at least one group that bonds (covalently or non-covalently) to an organic layer and at least one group that bonds (covalently or non-covalently) to an inorganic layer. Covalent bonding requires the group to react with the surface it is in contact with. For example, the following structure... [ka] Regarding the coupling agent 2-(3-trimethoxysilylpropylcarbamoyloxy)ethylpropano-2-enoic acid (K90), the acrylate group can react with other acrylates in the adjacent organic layer to form an acrylate copolymer. Other functional groups that can bond (covalently or non-covalently) to the (meth)acrylate coating include (meth)acrylate, vinyl, amine, urethane, urea, and thiol functional groups. Similarly, the trimethoxysilyl group can react with one or more metal M (e.g., silicon, aluminum) hydroxide groups in the adjacent inorganic layer, for example, once, twice, or three times, to form a -Si-OM- bond. Other groups, such as acidic groups like carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, or phosphate groups, may be non-covalently bonded via hydrogen bonds to a portion in either the organic or inorganic layer adjacent to the coupling agent. The coupling agent before bonding to at least one surface is a separate compound, and after bonding to at least one surface, it may be referred to as the "bonded coupling agent." Therefore, any inorganic atom such as silicon, phosphorus, titanium, or zirconium can still be part of the coupling agent. If such an inorganic atom is not the same as the metal M, in some embodiments its presence may be detectable by analytical methods.

[0038] Suitable coupling agents include, but are not limited to, functional silanes having hydrolyzable alkoxy or chlorinating groups bonded to silicon atoms, with (meth)acrylicsilane coupling agents being particularly useful. Such coupling agents are commercially available from Momentive, Gelest, Evonik, Shin-Etsu Chemical Co., Ltd., and others. Suitable silane materials may include functional groups that bond (covalently or non-covalently) to the (meth)acrylate coating, including (meth)acrylate, vinyl, amine, urethane, urea, and thiol functional groups. Suitable materials may include functional groups that bond (covalently or non-covalently) to the inorganic layer, such as hydrolyzable silane groups, acids (including phosphate groups, phosphonic acid groups, sulfonic acid groups, and carboxylic acid groups), and other groups such as phenols, polyphenols, amines, alcohols, and thiols. Examples include the acrylicsilane coupling agent 2-(3-trimethoxysilylpropylcarbamoyloxy)ethylpropane-2-enoic acid, and others as shown in U.S. Patent Nos. 7,799,888 (Arkles et al.); 9,029,586 (Arkles et al.); 9,254,506 (Roehrig et al.); 9,790,396 (Klun et al.); 9,982,160 (Klun et al.); 10,011,735 (Klun et al.), and others as shown in U.S. Patent Publication Nos. 2015 / 0203707 (Klun et al.) and 2015 / 0218294 (Klun et al.). Furthermore, suitable coupling agents having a phosphonic acid group include those described in U.S. Patent Publication No. 2020 / 0017623 (Ye et al.) and International Publication No. 2020 / 046654 (Lin et al.).

[0039] The coupling agent often first bonds covalently or noncovalently to the second layer, and then bonds to at least one of the coupling agents bonded to the first or second layer, thereby bonding the first and second layers together via the coupling agent. Alternatively, the coupling agent may be formed when the coupling agent bonds to one of the first or second layers and also to another coupling agent compound or other photoreactive components present (e.g., monomers, oligomers, or polymers). This is more likely to occur if the coupling agent exists as part of a coupling agent layer that is at least as thick as (or thicker than) the length of the coupling agent compound.

[0040] Optionally, the coupling agent comprises at least one of silicon, phosphorus, titanium, or zirconium. In some embodiments, the coupling agent comprises at least one functional group selected from acrylates, urethanes, ureas, alkylenes, ureids, isocyanates, epoxys, alcohols, amines, thiols, phenols, aminos, and acids, a heteroatom, and at least one of silicon, phosphorus, titanium, or zirconium.

[0041] If the nanostructured first surface of the first layer contains convex nanofeatures, the binding coupling agent is bound to a portion of the convex nanofeatures. If all the nanofeatures on the nanostructured first surface of the first layer are concave nanofeatures, the binding coupling agent is bound to a portion of the main surface of the first layer. In some embodiments, the first main surface of the second layer is covalently bonded to a portion of the nanostructured first surface of the first layer via the binding coupling agent. As used herein, the term “residue” is used to define the portion of the coupling agent remaining after the removal of groups capable of forming bonds (covalent or non-covalent) to the first and second layers. Typically, covalent bonds are stronger than non-covalent bonds.

[0042] As mentioned above, coupling agents become residues only when both terminal groups are removed during the reaction. For example: [ka] The "residue" of the coupling agent 2-(3-trimethoxysilylpropylcarbamoyloxy)ethylpropanoic acid (K90) shown is -CH2CH2OC(O)NHCH2CH2-CH2-.

[0043] Another example of a coupling agent is: [ka] That is the case.

[0044] The residue of this coupling agent is -CH2CH2OC(O)CH2CH2-.

[0045] In some cases, for example, [ka] Regarding this, the coupling agent residues are covalently bonded.

[0046] The coupling agent residues are the "core" of the coupling agent that remains after the reaction between the terminal functional groups and the first and second layers.

[0047] In some embodiments, the coupling agent exists as a coupling agent layer having a thickness of less than 100 nanometers (nm), 90 nm, 80 nm, 70 nm, 60 nm, 50 nm, 40 nm, 30 nm, or less than 25 nm, and a thickness of 5 nm or more. In such embodiments, at least one enclosed void is defined by the nanostructured first surface of the first layer and the first main surface of the coupling agent layer. For example, referring to Figures 2B-2C, the coupling agent exists as a coupling agent layer 111, and the enclosed void 130 is defined by the nanostructured first surface 112 of the first layer 110 and the first main surface 113 of the coupling agent layer 111. In such embodiments, molecules of the coupling agent located on or near the first main surface of the coupling agent layer often bind to the nanostructured first surface of the first layer, while other molecules of the coupling agent located on or near the opposite main surface of the coupling agent layer bind to the first main surface of the second layer. In coupling agent layers of greater thickness, more coupling agent molecules are located between the two main surfaces of the coupling agent layer than in coupling agent layers of less thickness. Optionally, coupling agent molecules located within the bulk of the coupling agent layer bond to each other and / or other photoreactive components when the first and second layers are bonded together.

[0048] In some embodiments, the coupling agent directly bonds the first main surface of the second layer to the nanostructured first surface of the first layer. In such embodiments, at least one enclosed void is defined by the nanostructured first surface of the first layer and the first main surface of the second layer.

[0049] Referring again to Figure 1, in the embodiment shown, article 1000 further includes a third layer 140 attached to a second surface 116 opposite to the first layer 110. In some embodiments, article 1000 further includes a fourth layer 150 attached to a second main surface 124 of the second layer 120. The preferred third and / or fourth layers include inorganic and organic materials, and in some embodiments, the third layer 140, the fourth layer 150, or both include polymer layers. Either or both of the third or fourth layers may be referred to as a substrate. Suitable materials for polymer substrates include copolyester polymers such as polyethylene terephthalate (PET) and glycol-modified polyethylene terephthalate (PETg), cycloolefin polymers (COP), cycloolefin copolymers (COC), poly(ethylene naphthalate) (PEN), polycarbonate (PC), acrylate polymers such as alicyclic acrylates, or poly(methyl methacrylate) (PMMA), polyimide (PI), polysulfone, and cast cellulose diacetate, as well as mixtures or copolymers containing these materials. The thickness of the substrate is not particularly limited and may range from 1 micrometer to 1 centimeter, 5 micrometers to 1 centimeter, 10 micrometers to 500 millimeters, or 50 micrometers to 250 millimeters. In other words, the polymer substrate may have a thickness of 1 micrometer or more, 2 micrometers or more, 3 micrometers or more, 5 micrometers or more, 7 micrometers or more, 10 micrometers or more, 20 micrometers or more, 35 micrometers or more, 50 micrometers or more, 75 micrometers or more, 100 micrometers or more, 250 micrometers or more, 500 micrometers or more, 750 micrometers or more, or 1 millimeter or more; and a thickness of 1 centimeter or less, 9 millimeters or less, 8 millimeters or less, 7 millimeters or less, 6 millimeters or less, 5 millimeters or less, 3.5 millimeters or less, 2.5 millimeters or less, 1 millimeter or less, 0.50 millimeters or less, 0.25 millimeters or less, or 0.10 millimeters or less.Furthermore, additional suitable substrates may include painted or patterned substrates, including metals, plastics, and glass.

[0050] In certain embodiments, one or both of the third layer 140 or the fourth layer 150 comprises a polymer film. The polymer “film” is a polymer material in the form of a substantially flat sheet that is flexible and strong enough to be processed in a roll-to-roll manner. The polymer film used in the articles described herein may be referred to as the base film. Roll-to-roll means a process in which a material is wound onto or unwound from a support and then further processed in some way. Examples of further processes include coating, laminating, slitting, die-cutting, and exposure to radiation. The polymer film can be manufactured in various thicknesses, generally ranging from about 5 micrometers to 1000 micrometers. Similarly, the first layer may comprise a film that is substantially flat except for the nanostructured surface.

[0051] Optionally, one or both of the third layer 140 or the fourth layer 150 include a low birefringence layer. "Low birefringence" means a layer having an optical phase delay of 25 nm or less at one or more wavelengths of interest (e.g., visible or infrared wavelengths). The optical phase delay of the layer can be measured using a polarimeter such as the AXOSCAN Mueller Matrix Polarimeter (available from Axometrics Inc. (Huntsville, AL)). Suitable materials for the low birefringence layer include, for example, polysulfones, acrylate polymers such as polymethyl methacrylate and alicyclic acrylate, polycarbonate polymers, cycloolefin polymers and copolymers, copolyester polymers (e.g., PETg), and cast cellulose diacetate.

[0052] Preferably, the article is transparent to visible light. The advantage of having an article that is transparent to visible light is its suitability for many applications. For example, the article may be useful as an optical element such as a diffraction grating, or in augmented reality waveguide applications.

[0053] Examples of suitable materials for the first layer 110 include high refractive index organic materials, polymer materials filled with nanoparticles, polymers filled with high refractive index inorganic materials, and high refractive index conjugated polymers. Examples of high refractive index polymers and monomers are described in Chem. Mater. 7, 1276 (1995) by C. Yang et al., Polymer 31, 627 (1990) by R. Burzynski et al., and U.S. Patent No. 6,005,137, all of which are incorporated herein by reference to the extent not inconsistent with this specification. Examples of polymers filled with high refractive index inorganic materials are described in U.S. Patent No. 6,329,058. Examples of nanoparticles in polymer materials filled with nanoparticles include high refractive index materials such as TiO2, ZrO2, HfO2, or other inorganic materials. In some embodiments, suitable materials for the first layer 110 include low refractive index materials such as those described in U.S. Patent No. 8,012,567 (Gaides et al.), or ultra-low refractive index materials such as those described in U.S. Patent Application Publication No. 2012 / 0038990 (Hao et al.). In selected embodiments, the first layer 110 comprises an acrylic polymer or copolymer, e.g., at least one polymerizable component selected from (meth)acrylate monomers, (meth)acrylate oligomers, and mixtures thereof. As used herein, “monomer” or “oligomer” refers to any substance that can be converted into a polymer. The term “(meth)acrylate” refers to both acrylate compounds and methacrylate compounds.

[0054] In some embodiments, the polymerizable composition used to form the first layer comprises a crosslinking agent (e.g., alone) as a (meth)acrylate monomer containing at least three (meth)acrylate functional groups. In some embodiments, the crosslinkable monomer contains at least four, five, or six (meth)acrylate functional groups. Acrylate functional groups tend to be preferred over (meth)acrylate functional groups. Preferred commercially available crosslinking agents include, for example, trimethylolpropane triacrylate (commercially available from Sartomer Company (Exton, PA) under the trade name "SR351"), ethoxylated trimethylolpropane triacrylate (commercially available from Sartomer Company under the trade name "SR454"), pentaerythritol tetraacrylate, pentaerythritol triacrylate (commercially available from Sartomer Company under the trade name "SR444"), dipentaerythritol pentaacrylate (commercially available from Sartomer Company under the trade name "SR399"), ethoxylated pentaerythritol tetraacrylate, ethoxylated pentaerythritol triacrylate (commercially available from Sartomer under the trade name "SR494"), dipentaerythritol hexaacrylate, and tris(2-hydroxyethyl) isocyanurate triacrylate (commercially available from Sartomer under the trade name "SR368").

[0055] Useful multi(meth)acrylate monomers and oligomers include the following: (a) Di(meth)acrylic-containing monomers, e.g., 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol monoacrylate monomethacrylate, ethylene glycol diacrylate, alkoxylated aliphatic diacrylate, alkoxylated cyclohexanedimethanol diacrylate, alkoxylated hexanediol diacrylate, alkoxylated neopentyl glycol diacrylate, caprolactone-modified neopentyl glycol hydroxypivalate diacrylate, caprolactone-modified neopentyl glycol Dihydroxypivalate diacrylate, cyclohexanedimethanol diacrylate, diethylene glycol diacrylate, dipropylene glycol diacrylate, ethoxylated bisphenol A diacrylate, hydroxypivalaldehyde-modified trimethylolpropane diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, propoxylated neopentyl glycol diacrylate, tetraethylene glycol diacrylate, tricyclodecanedimethanol diacrylate, triethylene glycol diacrylate, and tripropylene glycol diacrylate. (b) Tri(meth)acrylic-containing monomers, e.g., glycerol triacrylate, trimethylolpropane triacrylate, ethoxylated triacrylate (e.g., ethoxylated trimethylolpropane triacrylate), propoxylated triacrylate (e.g., propoxylated glyceryl triacrylate, propoxylated trimethylolpropane triacrylate), trimethylolpropane triacrylate, and tris(2-hydroxyethyl) isocyanurate triacrylate, and (c) More polyfunctional (meth)acrylic-containing monomers, such as ditrimethylolpropanetetraacrylate, dipentaerythritol pentaacrylate, pentaerythritol triacrylate, ethoxylated pentaerythritol tetraacrylate, and caprolactone-modified dipentaerythritol hexaacrylate.

[0056] In one embodiment, a suitable polymerizable composition comprises at least one monomer or oligomer (meth)acrylate, preferably a urethane (meth)acrylate. Typically, the monomer or oligomer (meth)acrylate is a multi(meth)acrylate. The term "(meth)acrylate" is used to represent esters of acrylic acid and methacrylic acid, and "multi(meth)acrylate" refers to a molecule containing two or more (meth)acrylate groups, in contrast to "poly(meth)acrylate," which generally refers to (meth)acrylate polymers. In most cases, the multi(meth)acrylate is a di(meth)acrylate, but the use of tri(meth)acrylate, tetra(meth)acrylate, etc., is also conceivable. Suitable monomer or oligomer (meth)acrylates include alkyl(meth)acrylates such as methyl acrylate, ethyl acrylate, 1-propyl acrylate, methyl methacrylate, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, and t-butyl acrylate. The acrylate may contain a (fluoro)alkyl ester monomer of (meth)acrylic acid, the monomer being partially and / or completely fluorinated, for example, trifluoroethyl (meth)acrylate.

[0057] Examples of commercially available multi(meth)acrylate resins include the DIABEAM series from Mitsubishi Rayon; the DINACOL series from Nagase & Co., Ltd.; the NK ESTER series from Shin Nakamura Chemical Industries; the UNIDIC series from Dainippon Ink and Chemicals, Ltd.; the ARONIX series from Toagosei Co., Ltd.; the BLENMER series from NOF Corp.; the KAYARAD series from Nippon Kayaku Co., Ltd.; and the LIGHT ESTER series and LIGHT ACRYLATE series from Kyoeisha Chemical Co., Ltd.

[0058] Oligomer urethane multi(meth)acrylates are commercially available, for example, from IGM Resins under the trade names "PHOTOMER 6000 Series," such as "PHOTOMER 6010" and "PHOTOMER 6210," and from Sartomer Company under the trade names "CN 900 Series," such as "CN966B85," "CN964," and "CN972." Oligomer urethane(meth)acrylates are also available from Surface Specialties under the trade names "EBECRYL 8402," "EBECRYL 8807," and "EBECRYL 4827." Oligomer urethane(meth)acrylates can also be prepared by the initial reaction of alkylene or aromatic diisocyanate of formula OCN-R3-NCO with a polyol. In most cases, the polyol is a diol of the formula HO-R4-OH, where R3 is a C2-100 alkylene or arylene group, and R4 is a C2-100 alkylene group. The alkylene and arylene groups may also contain ether or ester groups. In this case, the intermediate product is a urethane diol diisocyanate, which can then react with a hydroxyalkyl (meth)acrylate. Preferred diisocyanates include 2,2,4-trimethylhexylene diisocyanate and toluene diisocyanate. Generally, alkylene diisocyanates are preferred. Particularly preferred compounds of this type can be prepared from hexane diisocyanate, poly(caprolactone)diol, and 2-hydroxyethyl methacrylate. In at least some cases, the urethane (meth)acrylate is preferably aliphatic.

[0059] A polymerizable composition may be a mixture of various monomers and / or oligomers having the same or different reactive functional groups. A polymerizable composition containing two or more different functional groups, including (meth)acrylates, epoxy, and urethanes, may be used. Different functionalities may be contained in different monomer and / or oligomer moieties, or in the same monomer and / or oligomer moiety. For example, a resin composition may contain acrylic or urethane resins having epoxy and / or hydroxyl groups in their side chains, compounds having amino groups, and optionally, silane compounds having epoxy or amino groups in their molecules.

[0060] The composition can be polymerized using conventional techniques such as thermosetting, photocuring (chemical beam curing), and / or electron beam curing. In one embodiment, the composition is photopolymerized by exposure to ultraviolet (UV) and / or visible light. More generally, photopolymerizable compositions are typically cured using chemical beams such as ultraviolet, electron beam radiation, visible radiation, or any combination thereof. Those skilled in the art can select a suitable radiation source and wavelength range for a particular application without excessive experimentation.

[0061] Conventional curing agents and / or catalysts may be used in the polymerizable composition and may be selected based on the functional groups in the composition. When multiple curing functional groups are used, multiple curing agents and / or catalysts may be required. Combining one or more curing techniques such as thermosetting, photocuring, and electron beam curing is within the scope of this disclosure.

[0062] Furthermore, the polymerizable composition may contain at least one other monomer and / or oligomer (i.e., other than those mentioned above, i.e., (meth)acrylates of monomers or oligomers, and urethane (meth)acrylates of oligomers). These other monomers may reduce viscosity and / or improve thermomechanical properties and / or increase refractive index. Examples of monomers having these properties include acrylic monomers (i.e., acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides), styrene monomers, and ethylenically unsaturated nitrogen heterocycles.

[0063] Other functional (meth)acrylate esters are also included. These types of compounds are represented by 2-(N-butylcarbamyl)ethyl (meth)acrylate, 2,4-dichlorophenyl acrylate, 2,4,6-tribromophenyl acrylate, tribromophenoxyethyl acrylate, t-butylphenyl acrylate, phenyl acrylate, phenylthioacrylate, phenylthioethyl acrylate, alkoxylated phenyl acrylate, isobornyl acrylate, and phenoxyethyl acrylate. Reaction products of tetrabromobisphenol A diepoxide and (meth)acrylic acid are also preferred. Other monomers may also be monomer N-substituted or N,N-disubstituted (meth)acrylamides, particularly acrylamides. These include N-alkylacrylamides and N,N-dialkylacrylamides, especially those containing C1-4 alkyl groups. Examples include N-isopropylacrylamide, Nt-butylacrylamide, N,N-dimethylacrylamide, and N,N-diethylacrylamide. The term "(meth)acrylamide" refers to both acrylamide and methacrylamide.

[0064] Suitable styrene compounds for use as other monomers include styrene, dichlorostyrene, 2,4,6-trichlorostyrene, 2,4,6-tribromostyrene, 4-methylstyrene, and 4-phenoxystyrene. Examples of ethylenically unsaturated nitrogen heterocycles include N-vinylpyrrolidone and vinylpyridine.

[0065] The photopolymerizable compositions according to this disclosure typically comprise at least one photoinitiator. Suitable exemplary photoinitiators are available from IGM Resins (Waalwijk, The Netherlands) under the trade name OMNIRAD, including 1-hydroxycyclohexylphenyl ketone (OMNIRAD 184), 2,2-dimethoxy-1,2-diphenylethane-1-one (OMNIRAD 651), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (OMNIRAD 819), 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one (OMNIRAD 2959), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (OMNIRAD 369), and 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one (OMNIRAD Examples of photoinitiators include 379), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (OMNIRAD 907), oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone]esacure one (Lamberti SpA, Gallarate, Italy), 2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR 1173), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (OMNIRAD TPO), and 2,4,6-trimethylbenzoylphenylphosphine (OMNIRAD TPO-L). Additional suitable photoinitiators include, but are not limited to, benzyldimethyl ketal, 2-methyl-2-hydroxypropiophenone, benzoin methyl ether, benzoin isopropyl ether, anisoin methyl ether, aromatic sulfonyl chloride, photoactive oximes, and combinations thereof.

[0066] In some embodiments, a cationic photoinitiator is present in a composition containing, for example, an epoxy component. Further, a thermal initiator may also optionally be present in the photopolymerizable composition described herein. For example, a free radical photoinitiator, a cationic photoinitiator, a thermal photoinitiator, or any combination thereof may be present in the photopolymerizable composition.

[0067] Suitable cationic photoinitiators include, for example, bis[4-diphenylsulfoniumphenyl]sulfide bishexafluoroantimonate, thiophenoxyphenylsulfonium hexafluoroantimonate (available as CHIVACURE 1176 from Chitec (Houston, TX)), tris(4-(4-acetylphenyl)thiophenyl)sulfonium tetrakis(pentafluorophenyl)borate, tris(4-(a 6-m (C n F 2n+1 ) m ) - (where m is an integer from 1 to 5 and n is an integer from 1 to 4) having an anion of an aromatic sulfonium salt (available as CPI-200K or CPI-200S, a monovalent sulfonium salt manufactured by San-Apro Ltd. (Kyoto, JP), TK-1 available from San-Apro Ltd., or HS-1 available from San-Apro Ltd.), but are not limited thereto.

[0068] In some embodiments, the photoinitiator is present in the photopolymerizable composition in an amount of up to about 5% by weight, based on the total weight of polymerizable components in the photopolymerizable composition (excluding components such as particles, for example). In some cases, the photoinitiator may be present in an amount of about 0.1–5% by weight, 0.2–5% by weight, or 0.5–5% by weight, based on the total weight of the photopolymerizable composition.

[0069] In some embodiments, the thermal initiator is present in the polymerizable composition in an amount of up to about 5% by weight, for example, about 0.1 to 5% by weight, based on the total weight of the polymerizable components in the polymerizable composition. Suitable thermal initiators include, but are not limited to, peroxides such as benzoyl peroxide, dibenzoyl peroxide, dilauryl peroxide, cyclohexane peroxide, methyl ethyl ketone peroxide, hydroperoxides such as tert-butyl hydroperoxide and cumene hydroperoxide, dicyclohexyl peroxydicarbonate, 2,2-azobis(isobutyronitrile), and t-butyl perbenzoate. Examples of commercially available thermal initiators include initiators available under the trade name VAZO from DuPont Specialty Chemical (Wilmington, DE), which include VAZO67 (2,2'-azobis(2-methylbutyronitrile)), VAZO64 (2,2'-azobis(isobutyronitrile)), and VAZO52 (2,2'-azobis(2,2-dimethylvaleronitrile)), as well as initiators available under the trade name LUCIDOL70 from Elf Atochem North America, Philadelphia, Pa.

[0070] When two or more initiators (e.g., a photoinitiator and / or a thermal initiator) are used in a polymerizable composition to form a layer, the resulting layer typically contains some residue of both the first initiator or initiator fragment and the second initiator or initiator fragment present in the layer.

[0071] Unexpectedly, in some embodiments, the adhesion between the first and second layers of the article is strong enough to exhibit a peel force of 5 grams / cm² or more, 7 g / cm² or more, 10 g / cm² or more, 12 g / cm² or more, 15 g / cm² or more, 17 g / cm² or more, 20 g / cm² or more, 22 g / cm² or more, 25 g / cm² or more, 27 g / cm² or more, 30 g / cm² or more, 32 g / cm² or more, 35 g / cm² or more, 37 g / cm² or more, 40 g / cm² or more, 42 g / cm² or more, 45 g / cm² or more, 47 g / cm² or more, or even 50 g / cm² or more; and 100 g / cm² or less, 90 g / cm² or less, 80 g / cm² or less, 70 g / cm² or less, or 60 g / cm² or less. In embodiments, instead of the two layers separating from each other, at least one of the first or second layers itself breaks. Layer failure means that the layer splits, breaks, or fragments, as opposed to maintaining its structural integrity. Peeling force (or layer failure) can be determined using the peeling force test method described in the following examples.

[0072] In a second embodiment, an optical element is provided. The optical element includes an article according to the first embodiment, which is described in detail above. Referring to Figures 3A to 3D, for example, SEM images of a section of an exemplary article of Example 2 (described in detail below) are shown. Figure 3A shows an article 300 having a magnification of 2,000x and including a first nanostructured surface comprising a plurality of nanofeatures 314, and a second layer 320 comprising glass and attached to a portion of the nanofeatures 114 of the first nanostructured surface. The article 300 further comprises a third layer 340 attached to a second surface 316 opposite to the first layer 310. The third layer 340 comprises a copolyester layer having a thickness of about 10 micrometers. Referring to Figure 3B (i.e., 10,000x magnification), the first layer 310, the nanostructured first surface 312 containing the nanofeatures 314, the second layer 320, and the coupling agent layer 311 attached to a portion of the nanofeatures 314 (Figures 3B-3D) are all shown. In the embodiment of Figure 3B, there is one connected void 330 surrounding many, almost all, or all of the (e.g., convex) nanofeatures 314. Referring to Figures 3C and 3D (i.e., 100,000x magnification), some of the shapes of the nanofeatures 314 in two separated nanostructured regions of the article (e.g., see Figure 4A) are more clearly visible.

[0073] Referring to Figure 4A, for example, a schematic cross-section of an exemplary article 400 of Example 2 is shown, where layer 410 is a first layer containing a nanostructured surface bonded to a second layer 420 containing glass, and includes a plurality of enclosed voids 430. Optical input LI directed to the first layer 410 enters article 400 at the position of input grating 440. A portion of the light exits article 400 through the second layer 420 as unbonded light NC. A portion of the light propagates in the direction of arrow GL as waveguide light through the glass of the second layer 420. After passing through the planar region of the first layer 410 lacking enclosed voids 430, a portion of the propagated light exits article 400 at output grating 450, for example, at four output spots (indicated, for example, by arrows pointing away from article 400). The propagated light can exit the article at various angles (not necessarily perpendicular to the article, for example, as indicated by the four arrows in Figure 4A). Factors that may affect the exit angle include, for example, the input coupling angle, the pitch of the nanofeatures in the input grating, and the refractive index difference between the glass and the input grating. The remainder of the propagated light exits the article 400 as scattered light 460 through the matte region 425 of the second layer 420. This article 400 may be useful in augmented reality waveguide applications. In one embodiment, the optical element includes a diffraction grating.

[0074] Figure 4B is a photograph of the article of Embodiment 2 in use. More specifically, Figure 4B shows a laser pointer 470 directing laser light onto article 400 of Figure 4A at the position of the optical input LI (e.g., at the input grating). Following propagation through article 400, as guided light, a portion of the propagated light 455 exits article 400 (e.g., at the output grating) to provide, for example, multiple overlapping light spots. Furthermore, some of the propagated light exits article 400 as scattered light 460 (e.g., through the matte region of the second layer).

[0075] method Various methods according to this disclosure may be used to prepare an article according to the first aspect described above. More specifically, a third aspect provides a method for manufacturing an article. The method is: a) To obtain a first layer comprising a nanostructured first surface containing nanofeatures and a second surface on the opposite side, wherein the nanostructured first surface contains concave features, convex features formed from a single composition, or both concave and convex features. b) The first main surface of the second layer is treated with a coupling agent to bond the coupling agent to the second layer, wherein the first main surface of the second layer contains an inorganic material. c) Bringing the treated first main surface of the second layer into contact with a portion of the nanostructured first surface of the first layer, d) Bonding the first layer and the second layer together via a coupling agent, wherein the coupling agent directly bonds the first main surface of the second layer to the nanostructured first surface of the first layer, or exists as a coupling agent layer. The nanostructured first surface of the first layer and either the first main surface or the coupling agent layer of the second layer cooperate to define at least one void.

[0076] Figure 5 is a flowchart of an exemplary manufacturing method for producing an article according to the present application. Referring to Figure 5, the method for producing an article includes a first layer comprising a nanostructured first surface containing nanofeatures and a second surface on the opposite side, wherein the nanostructured first surface contains concave features, convex features formed of a single composition, or both concave and convex features. The method then includes a step 520 of treating a first main surface of a second layer with a coupling agent to bond the coupling agent to the second layer, wherein the first main surface of the second layer contains an inorganic material. In any embodiment, treating (e.g., functionalizing) may include applying a coating of the coupling agent composition onto the first main surface of the second layer and drying the composition. Such a coupling agent composition typically comprises a coupling agent and a solvent. In certain embodiments, the coupling agent composition further comprises at least one of a photoinitiator or a thermal initiator. In some embodiments, the method further includes cleaning the treated first main surface of the second layer to remove unbonded (e.g., unreacted) coupling agents.

[0077] The method then includes step 530 of bringing the treated first main surface of the second layer into contact with a portion of the nanostructured first surface of the first layer. In any embodiment, the first layer is brought into contact with the second layer by laminating the first and second layers together. Lamination of layers is well known and often involves processes such as subjecting at least one outer main surface of the stack of layers to a loading roller or passing the stacked layers through a nip roller line or benchtop laminator.

[0078] In embodiments including any additional layers (e.g., a third layer, a fourth layer, etc.) attached to the main surface of the first or second layer, the additional layers are preferably attached to one of the first or second layers before the first layer is brought into contact with the second layer. For example, the second surface opposite the first layer may be attached to a substrate (e.g., a layer), and / or the second layer may have a second main surface attached to a substrate (e.g., a layer).

[0079] The method further includes step 540, which involves bonding (covalently or non-covalently) the first layer and the second layer together via a bonding coupling agent, wherein the bonding coupling agent directly bonds the first main surface of the second layer to the nanostructured first surface of the first layer, or exists as a coupling agent layer, and the nanostructured first surface of the first layer and the first main surface of the second layer cooperate to define at least one void. In any embodiment, the bonding (e.g., reaction) of step 540 may include subjecting the coupling agent bonded to the first layer and / or the second layer to a chemical beam. Preferred forms of chemical beam include ultraviolet (UV) light, visible light, electron beam, gamma, or any combination thereof. Alternatively, the first layer and / or coupling agent and the second layer are bonded by subjecting the first layer and / or the second layer to heat. The advantage of bonding one or more of the first layers or coupling agents to the second layer is that, especially when the nanofeatures are convex nanofeatures, the main surface of the second layer typically contacts only a portion of the nanostructured first surface rather than the entire main surface of the first layer, so the bonding creates a stronger connection between the first and second layers than would normally be achieved by applying physical pressure to the outer main surfaces of the first and second layers (e.g., lamination) alone. For example, crosslinking can be created between the first and second layers via a bonding coupling agent by reacting a crosslinkable material. In some embodiments, at least one of the first layers or coupling agents bonded to the second layer includes a partially cured material that reacts to fix the first and second layers together, for example, covalently bond the two layers together. Optionally, the first layer includes a photoinitiator, a thermal initiator, or both.

[0080] Selected Embodiments of the Disclosure In a first embodiment, the disclosure provides an article comprising: a) a first layer comprising a nanostructured first surface containing nanofeatures and a second surface on the opposite side; and b) a second layer comprising a first main surface and a second main surface on the opposite side, wherein the first main surface is bonded to a portion of the nanostructured first surface of the first layer. The nanostructured first surface comprises concave features, convex features formed of a single composition, or both concave and convex features. The second layer comprises an inorganic material. The article comprises at least one enclosed void partially defined by the nanostructured first surface of the first layer.

[0081] In a second embodiment, the disclosure provides an article according to the first embodiment, wherein the first main surface of the second layer is bonded to a portion of the nanostructured surface of the first layer via a bonding coupling agent.

[0082] In a third embodiment, the disclosure provides an article according to the second embodiment, wherein the coupling agent is present as part of a coupling agent layer having a thickness of less than 100 nanometers (nm), less than 50 nm, or less than 25 nm.

[0083] In a fourth embodiment, the disclosure provides an article according to the third embodiment, wherein at least one enclosed void is defined by the nanostructured first surface of the first layer and the first main surface of the coupling agent layer.

[0084] In a fifth embodiment, the disclosure provides an article according to the second or third embodiment, wherein the coupling agent directly bonds the first main surface of the second layer to the nanostructured first surface of the first layer.

[0085] In the sixth embodiment, the disclosure provides an article according to any one of the first, second, or fifth embodiments, wherein at least one enclosed void is defined by a nanostructured first surface of the first layer and a first principal surface of the second layer.

[0086] In the seventh embodiment, the disclosure provides an article according to any one of the first to sixth embodiments, wherein the inorganic material comprises an oxide, nitride, carbide, or boride of a metal or nonmetal, or a combination thereof.

[0087] In the eighth embodiment, the disclosure provides an article according to any one of the first to seventh embodiments, wherein the inorganic material comprises an oxide of titanium, indium, tin, tantalum, zirconium, niobium, aluminum, silicon, or a combination thereof.

[0088] In the ninth embodiment, the disclosure provides an article according to any one of the first to eighth embodiments, wherein the inorganic material includes glass.

[0089] In the tenth embodiment, the disclosure provides an article according to any one of the first to ninth embodiments, wherein the inorganic material is in the form of a self-supporting layer.

[0090] In the eleventh embodiment, the disclosure provides an article according to any one of the first to ninth embodiments, wherein the inorganic material is in the form of a non-self-supporting coating or layer, and the second layer comprises an inorganic material supported on a polymer material.

[0091] In a twelfth embodiment, the disclosure provides an article according to any one of the first to eleventh embodiments, wherein the second layer is substantially planar.

[0092] In a thirteenth embodiment, the disclosure provides an article according to any one of the first to twelfth embodiments, wherein at least one enclosed void contains gas.

[0093] In the fourteenth embodiment, the disclosure provides an article according to any one of the first to thirteenth embodiments, wherein the first layer is an organic layer.

[0094] In the fifteenth embodiment, the disclosure provides an article according to any one of the first to fourteenth embodiments, wherein the first layer comprises a polymer material.

[0095] In the sixteenth embodiment, the disclosure provides an article according to any one of the first to fifteenth embodiments, wherein the first layer comprises a crosslinking material or a crosslinkable material.

[0096] In the 17th embodiment, the disclosure provides an article according to any one of the first to 16 embodiments, wherein the first layer comprises an acrylic polymer or copolymer.

[0097] In the eighteenth embodiment, the disclosure provides an article according to any one of the first to seventeenth embodiments, wherein the coupling agent comprises at least one of silicon, phosphorus, titanium, or zirconium.

[0098] In the 19th embodiment, the disclosure provides an article according to any one of the first to 17th embodiments, wherein the coupling agent comprises at least one functional group selected from acrylates, urethanes, ureas, alkylenes, ureids, isocyanates, epoxys, alcohols, amines, thiols, phenols, aminos, and acids, a heteroatom, and at least one of silicon, phosphorus, titanium, or zirconium.

[0099] In the 20th embodiment, the disclosure provides an article according to any one of the first to 19 embodiments, wherein the height of the nanofeature is less than 1 micrometer and at least 10 nanometers.

[0100] In the 21st embodiment, the disclosure provides an article according to any one of the first to 20th embodiments, wherein the width of the nanofeature is less than 1 micrometer and at least 10 nanometers.

[0101] In the 22nd embodiment, the disclosure provides an article according to any one of the first to 21st embodiments, wherein the nanofeature includes at least one nonlinear surface in at least one direction.

[0102] In the 23rd embodiment, the disclosure provides an article according to any one of the first to 22 embodiments, wherein the nanostructured first surface includes concave features.

[0103] In the 24th embodiment, the disclosure provides an article according to any one of the first to 23 embodiments, wherein the nanostructured first surface comprises only concave features.

[0104] In the 25th embodiment, the disclosure provides an article according to any one of the first to 23 embodiments, wherein the nanostructured first surface includes convex features.

[0105] In the 26th embodiment, the disclosure provides an article according to any one of the first to 22nd or 25th embodiments, wherein the nanostructured first surface comprises only convex features.

[0106] In the 27th embodiment, the Disclosure provides an article according to any one of the 1st to 26th embodiments, which exhibits a peel force of 5 grams / cm (g / cm) or more, 10 g / cm or more, 20 g / cm or more, 30 g / cm or more, or 50 g / cm or more, as determined by a peel force test, or exhibits fracture of the first or second layer.

[0107] In the 28th embodiment, the Disclosure provides an article according to any one of the 1st to 27th embodiments, wherein the second layer has an average thickness of 1 nanometer, 10 nanometers, 50 nanometers, 100 nanometers, 500 nanometers, 1 micrometer, 2 micrometers, or more than 3 micrometers.

[0108] In the 29th embodiment, the disclosure provides an article according to any one of the first to 28 embodiments, further comprising a third layer attached to a second surface opposite to the first layer.

[0109] In the 30th embodiment, the disclosure provides an article according to the 29th embodiment, wherein the third layer comprises a polymer layer.

[0110] In the 31st embodiment, the disclosure provides an article according to the 29th or 30th embodiment, wherein the third layer includes a low birefringence layer.

[0111] In the 32nd embodiment, the disclosure provides an article according to any one of the first to 31st embodiments, further comprising a fourth layer attached to a second main surface of the second layer.

[0112] In the 33rd embodiment, the disclosure provides an article according to the 32nd embodiment, wherein the fourth layer comprises a polymer layer.

[0113] In the 34th embodiment, the disclosure provides an article according to the 32nd or 33rd embodiment, wherein the fourth layer includes a low birefringence layer.

[0114] In the 35th embodiment, the disclosure provides an article according to any one of the first to 34 embodiments, wherein the second layer is nonporous.

[0115] In the 36th embodiment, the disclosure provides an article according to any one of the first to 35 embodiments, wherein the first layer further comprises a first initiator or initiator fragment and a second initiator or initiator fragment.

[0116] In the 37th embodiment, the disclosure provides an article according to any one of the first to 17th embodiments or the 20th to 36th embodiments, wherein the first main surface of the second layer is covalently bonded to a portion of the nanostructured first surface of the first layer via a bonding coupling agent.

[0117] In the 38th embodiment, the present disclosure provides an optical element comprising an article described in any one of the first to 37th embodiments.

[0118] In the 39th embodiment, the Disclosure provides a method for manufacturing an article. The method comprises: a) obtaining a first layer comprising a nanostructured first surface containing nanofeatures and a second surface on the opposite side; b) treating a first main surface of the second layer with a coupling agent to bond the coupling agent to the second layer, wherein the first main surface of the second layer contains an inorganic material; c) bringing the treated first main surface of the second layer into contact with a portion of the nanostructured first surface of the first layer; and d) bonding the first layer and the second layer together via a coupling agent, wherein the coupling agent either directly bonds the first main surface of the second layer to the nanostructured first surface of the first layer or exists as part of a coupling agent layer. The nanostructured first surface comprises concave features, convex features formed from a single composition, or both concave and convex features. The nanostructured first surface of the first layer and either the first main surface or the coupling agent layer of the second layer cooperate to define at least one void.

[0119] In the 40th embodiment, the disclosure provides a method according to the 39th embodiment, wherein bonding comprises subjecting the first layer, the coupling agent bonded to the second layer, or both to a chemical beam.

[0120] In the 41st embodiment, the disclosure provides a method according to the 40th embodiment, wherein the chemical beam includes ultraviolet (UV) light, visible light, an electron beam, gamma, or any combination thereof.

[0121] In the 42nd embodiment, the disclosure provides a method according to any one of the 39th to 41st embodiments, wherein bonding comprises subjecting the first layer, the coupling agent bonded to the second layer, or both to heat.

[0122] In the 43rd embodiment, the disclosure provides a method according to any one of the 39th to 42nd embodiments, wherein the first layer, the coupling agent bonded to the second layer, or both, comprises a partially cured material, and the partially cured material reacts to covalently bond the first layer and the second layer together.

[0123] In the 44th embodiment, the disclosure provides a method according to any one of the 39th to 43rd embodiments, wherein the first layer comprises a photoinitiator, a thermal initiator, or both.

[0124] In the 45th embodiment, the disclosure provides a method according to any one of the 39th to 44th embodiments, wherein the second surface opposite the first layer adheres to the substrate.

[0125] In the 46th embodiment, the disclosure provides a method according to any one of the 39th to 45th embodiments, wherein the second layer includes a second main surface attached to the substrate.

[0126] In the 47th embodiment, the disclosure provides a method according to any one of the 39th to 46th embodiments, wherein contacting the second layer and the first layer together is performed by laminating them.

[0127] In the 48th embodiment, the disclosure provides a method according to any one of the 39th to 47th embodiments, wherein the processing comprises applying a coating of the coupling agent composition onto a first main surface of a second layer and drying the composition.

[0128] In the 49th embodiment, the disclosure provides the method according to the 48th embodiment, wherein the coupling agent composition comprises a coupling agent, a solvent, and at least one of a photoinitiator or a thermal initiator.

[0129] In the 50th embodiment, the disclosure provides a method according to any one of the 39th to 49th embodiments, further comprising cleaning the treated first main surface of the second layer to remove any unbonded coupling agent. [Examples]

[0130] The advantages and embodiments of the present invention will be further described by the following examples, but the specific materials and their quantities, as well as other conditions and details, described in these examples should not be construed as unduly limiting the invention. Unless otherwise stated or unless readily apparent from the context, all parts, percentages, ratios, etc., in the examples and elsewhere in this specification are by weight.

[0131] [Table 1]

[0132] Test method Peeling force test Peeling force was evaluated by performing a 180° peel test using a Slip / Peel Tester (available from iMass, Inc. (Accord, MA) under the trade name "IMASS SP-2100"). The test specimen was mounted on the SP-2100 platen by attaching the glass slide side of the laminate to the platen using 1-inch (2.54 cm) wide 3M Removable Repositionable Tape 665. The laminate was separated at the film / glass interface, and the film was mounted on an iMass load cell. The platen was advanced at 0.508 centimeters per second (cm / second), and the force was recorded for 10 seconds. The average peeling force over that time was reported.

[0133] SEMICAL The outer three layers of the multilayer film of the film / glass laminate test specimen were removed. The resulting structure was cut in cross-section by holding the specimen with pliers and immediately after immersing it in liquid nitrogen, crushing the laminate with a small brass hammer. This procedure was performed so that the polymer layer region was crushed with minimal deformation. The cross-section was metal-plated (<2 nm thick AuPd alloy) and imaged with a Hitachi 4700 field emission scanning electron microscope under conditions observed to not affect the specimen.

[0134] Preparation example: First, a polyurethane acrylate mixture was prepared by adding 540 g of HMDI to 1000 g of TERETHANE 1000 and then adding 0.38 g of dibutyltin dilaurate as a catalyst. This isocyanate-terminated prepolymer was further reacted with 239.4 g of HEA in the presence of 1.4 g of BHT and 0.1 g of MEHQ. Fourier transform infrared spectroscopy was performed at 2275 cm⁻¹. -1 The reaction was considered complete when the isocyanate peak disappeared from the vicinity. The resulting polyurethane acrylate was then diluted with 1021 g of SR454.

[0135] Unless otherwise specified, after adding all ingredients, the resin composition was blended by heating it to approximately 50°C and mixing it in a roller mixer for 12 hours. The mixture was blended until it appeared homogeneous.

[0136] Resin A was produced by mixing polyurethane acrylate mixture, SR602, SR601, SR351, and ETERMER 210 in weight ratios of 60 / 20 / 4 / 8 / 8, respectively.

[0137] Resin B was prepared by adding IRGACURE TPO, DAROCUR 1173, and IRGANOX 1035 to 100 parts of resin A in a weight ratio of 0.35 / 0.1 / 0.2 parts, respectively, and mixing.

[0138] Resin C was prepared by mixing PHOTOMER 6210, SR238, SR351, and IRGACUR TPO in a weight ratio of 60 / 20 / 20 / 0.5.

[0139] Resin D was prepared as an example of the invention of U.S. Patent No. 9,360,591, using a carboxylic acid nanoparticle surface modifier such as that described in U.S. Patent No. 8,530,572. The resulting resin D had a refractive index of 1.67 at a wavelength of 633 nm.

[0140] Mixture A was prepared by mixing K90, DAROCURE 1173, and 2-propanol in a weight ratio of 0.1 / 0.002 / 100, respectively.

[0141] Film A was prepared by first preparing a multilayer film using the method described in International Publication No. 2019 / 032635(A1) (Johnson et al.). The resulting multilayer film had a 43-micrometer polyethylene terephthalate (PET) layer, a 6-7 micrometer linear triblock copolymer layer ("KRATON G1645"), a 6-7 micrometer layer containing a blend of 60 parts by weight of polypropylene ("PP9074MED") and 40 parts by weight of triblock copolymer ("KRATON G1645"), and a 15-micrometer copolyester layer ("EASTAR GN071"). Resin B was die-coated onto the copolyester surface of the multilayer film by passing it from a heated storage container through a heated hose and heated die, all set to 65.5°C. The coated side of the film was pressed onto a nanostructured nickel surface mounted on a steel roller controlled to 71°C, using a rubber-coated roller at a speed of 7.6 meters per minute (m / min). The coating thickness of resin B on the film was sufficient to completely wet the nickel surface and form rolling beads of resin when the coated film was pressed onto the nanostructured nickel surface. The resin-coated film was exposed to radiation from a Phoseon UV LED curing system (obtained from Phoseon Technologies (Hillsboro, OR) under the trade name "FIREJET FJ 300X20AC405-12W") operating at 100% power while in contact with the nanostructured nickel surface. Nanostructured film A was peeled off from the nanostructured nickel surface.

[0142] Film B was prepared by first die-coating resin C at room temperature onto a multilayer film used to manufacture film A. The coated film was pressed at a speed of 15.2 m / min using a rubber-coated roller onto a nanostructured nickel surface mounted on a steel roller controlled to 60°C. The nanostructured nickel surface had two regions of linear nanostructured features, the first nanostructured region having a nominal pitch between features of 400 nanometers, and the second nanostructured region having a nominal pitch between features of 600 nanometers. The coating thickness of resin C on the film was sufficient to completely wet the nickel surface and form rolling beads of resin when the coated film was pressed onto the nanostructured nickel surface having the two regions of linear nanostructure. The film was exposed to radiation from two Fusion UV lamp systems (obtained from Fusion UV Systems (Gaithersburg, MD) under the trade name "F600"), both fitted with D-valves operating at 142 W / cm, while in contact with the nanostructured nickel surface. After peeling the film from the nanostructured nickel surface, the nanostructured side of the film was again exposed to radiation from a Fusion UV lamp system operating at 142 W / cm.

[0143] A silicon-containing peel layer, developed using the methods described in U.S. Patent No. 6,696,157 (David et al.) and No. 8,664,323 (Iyer et al.), and U.S. Patent Application Publication No. 2013 / 0229378 (Iyer et al.), was applied to a nanostructured film in a parallel-plate capacitively coupled plasma reactor. The chamber was 1.7 m 2 (18.3ft 2The reactor has a central cylindrical powered electrode with a surface area of ​​). After placing the nanostructured film on the powered electrode, the reactor chamber was pumped down to a base pressure of less than 1.3 Pa (2 milliliters). O2 gas was introduced into the chamber at a flow rate of 1000 SCCM. The process was carried out using plasma-enhanced CVD by coupling RF power to the reactor at a frequency of 13.56 MHz and an applied power of 2000 watts. The processing time was controlled by moving the nanostructured film through the reaction area at a speed of 9.1 meters / min (30 feet / min), resulting in an approximate exposure time of 10 seconds. After the completion of deposition, the RF power was turned off and the gas was evacuated from the reactor. Following the first treatment, a second plasma treatment was performed in the same reactor without returning the chamber to atmospheric pressure. HMDSO gas was flowed into the chamber at approximately 1750 SCCM to achieve a pressure of 9 milliliters. Next, 13.56 MHz RF power was coupled to the reactor with an applied power of 1000 W. Then, the film was transported through the reaction area at a speed of 9.1 meters / minute (30 feet / minute), resulting in an approximate exposure time of 10 seconds. At the end of this processing time, the RF power and gas supply were stopped, the chamber was returned to atmospheric pressure, and the resulting film B was removed from the chamber.

[0144] Film C was prepared using the method described in International Publication No. 2019 / 032635(A1) (Johnson et al.). The resulting multilayer film had a 43 micrometer polyethylene terephthalate (PET) layer, a 6-7 micrometer linear triblock copolymer layer ("KRATON G1645"), a 6-7 micrometer layer containing a blend of 70 parts by weight of polypropylene ("PP9074MED") and 30 parts by weight of triblock copolymer ("KRATON G1645"), and a 10 micrometer copolyester layer ("EASTAR GN071").

[0145] Glass microscope slides (available from Fisher Scientific (Pittsburgh, PA) under product name Premium Microscope Slides, Cat number 12-544-2) were cleaned by immersing the slides in an ozone cleaner (available from Jelight Company (Irvine, CA) under product name UVO Cleaner Model 144AX) for 5 minutes. Mixture A was applied to the glass slides by placing a few drops of mixture A along the leading edge of each slide. Mixture A was spread onto the slides using a No. 7 wound coating rod (available from RD Specialties, Inc. (Webster, NY) under product name RDS07). Mixture A was then allowed to dry at ambient temperature for approximately 1 minute. The coated glass slides were placed in an oven set to 76°C for 60 minutes.

[0146] Example 1 Film A was laminated to the coated side of a coated glass slide using a hand ink roller. The laminated structure was then exposed to radiation from a UV lamp system (obtained from Fusion UV Systems (Gaithersburg, MD) under the trade name "F600") fitted with a D-valve operating at a speed of 25 feet per minute (7.62 meters per minute) and 236 watts / cm².

[0147] Three laminates were tested according to the peel strength test described above, and the average peel strength of the three laminates was 23 grams / centimeter (g / cm).

[0148] One laminate was analyzed using the SEM imaging described above, and the resulting images are shown in Figures 2A to 2C.

[0149] Example 2 Film B was bonded to a 1.6 mm thick aluminum plate with the nanostructured side facing up. Then, one piece of film C was placed on top of film B with the copolyester side facing down, and tape was used to bond it to film B along its leading edge. Beads of resin D were placed along the leading edge of the structure between the two films. The two films were pressed together using a hand roller, spreading resin D between them. The laminated structure was placed in an oven set to 60°C for 1 minute. The aluminum plate, film B, resin D, and the structure of film C were then exposed to radiation from a Phoseon UV LED curing system ("FIREJET FJ 300X20AC405-12W") operating at 10% power at a speed of 30.5 m / min. Film C and the cured resin D structure were removed from film B. The nanostructured resin D surface of film C and the resin D structure was pressed against the coated side of a glass slide. The structure, consisting of film C, resin D, and glass slide, was pressed with film C facing the UV lamp system at a speed of 25 feet per minute (ft / min) (7.62 meters / min) under UV light from a Fusion UV lamp system ("F600") equipped with a D bulb operating at 236 W / cm.

[0150] Example 2 was prepared by removing polyethylene terephthalate, a linear triblock copolymer layer, and a layer containing a blend of polypropylene and triblock copolymer from the film C side of the structure of film C, resin D, and glass slide. The first nanostructured region of Example 2 was irradiated with a red laser pointer as shown in Figures 4A to 4B. A portion of the light from the laser pointer coupled to Example 2 via the first nanostructured region propagated in Example 2, and a portion of the propagated light was extracted in the second nanostructured region. The first and second nanostructured regions of Example 2 were analyzed using the SEM imaging described above, and the obtained images are shown in Figures 3A to 3D.

[0151] All of the above-mentioned patents and patent applications are expressly incorporated herein by reference. In the event of any conflict between the disclosures of this application and the disclosures of any of the documents incorporated herein by reference, the disclosures of this application shall prevail. The embodiments described above are illustrative of the present invention, and other structures are also possible. Accordingly, the present invention should not be considered limited to the embodiments described in detail above and shown in the accompanying drawings, but rather limited only to the reasonable scope of the following claims, including their equivalents.

Claims

1. Articles, a) A first layer comprising a nanostructured first surface containing nanofeatures and a second surface on the opposite side, wherein the nanostructured first surface contains concave features, convex features formed from a single composition, or both concave and convex features, b) A second layer comprising a first main surface and a second main surface on the opposite side, wherein the first main surface is bonded to a portion of the nanostructured first surface of the first layer via a bonding coupling agent, Includes, The article comprises at least one enclosed void partially defined by the nanostructured first surface of the first layer, and the second layer comprises an inorganic material. An article wherein the coupling agent directly bonds the first main surface of the second layer to the nanostructured first surface of the first layer.

2. The article according to claim 1, wherein the coupling agent is present as part of a coupling agent layer having a thickness of less than 100 nanometers (nm), less than 50 nm, or less than 25 nm.

3. The article according to claim 1 or 2, wherein the inorganic material comprises a metallic or nonmetallic oxide, nitride, carbide, or boride, or a combination thereof, and optionally, the inorganic material comprises an oxide of titanium, indium, tin, tantalum, zirconium, niobium, aluminum, silicon, or a combination thereof.

4. The article according to any one of claims 1 to 3, wherein the inorganic material includes glass.

5. The article according to any one of claims 1 to 4, wherein the inorganic material is in the form of a self-supporting layer.

6. Articles, a) A first layer comprising a nanostructured first surface containing nanofeatures and a second surface on the opposite side, wherein the nanostructured first surface contains concave features, convex features formed from a single composition, or both concave and convex features, b) A second layer comprising a first main surface and a second main surface on the opposite side, wherein the first main surface is bonded to a portion of the nanostructured first surface of the first layer via a bonding coupling agent, Includes, The article comprises at least one enclosed void partially defined by the nanostructured first surface of the first layer, and the second layer comprises an inorganic material. An article wherein the inorganic material is in the form of a non-self-supporting coating or layer, and the second layer comprises the inorganic material supported on a polymer material.

7. The article according to any one of claims 1 to 6, wherein the first layer comprises a crosslinking material or a crosslinkable material.

8. The article according to any one of claims 1 to 7, wherein the coupling agent comprises at least one functional group selected from acrylate, urethane, urea, alkylene, ureid, isocyanate, epoxy, alcohol, amine, thiol, phenol, amino, and acid, a heteroatom, and at least one of silicon, phosphorus, titanium, or zirconium.

9. The article according to any one of claims 1 to 8, wherein the second layer is nonporous and optionally the at least one enclosed void contains gas.

10. An optical element comprising the article described in any one of claims 1 to 9.

11. A method for manufacturing articles, a) To obtain a first layer comprising a nanostructured first surface containing nanofeatures and a second surface on the opposite side, wherein the nanostructured first surface contains concave features, convex features formed from a single composition, or both concave and convex features, b) The first main surface of the second layer is treated with a coupling agent to bond the coupling agent to the second layer, wherein the first main surface of the second layer contains an inorganic material. c) Bringing the treated first main surface of the second layer into contact with a portion of the nanostructured first surface of the first layer, d) Bonding at least one of the first layer or the reaction products of the coupling agent to the second layer, thereby bonding the first layer and the second layer together via the coupling agent, wherein the coupling agent directly bonds the first main surface of the second layer to the nanostructured first surface of the first layer. Includes, A method wherein the nanostructured first surface of the first layer and the first main surface of the second layer cooperate to define at least one void.

12. The method according to claim 11, wherein the bonding includes subjecting the first layer, the coupling agent bonded to the second layer, or both, to chemical radiation, heat, or both.

13. A method for manufacturing articles, a) To obtain a first layer comprising a nanostructured first surface containing nanofeatures and a second surface on the opposite side, wherein the nanostructured first surface contains concave features, convex features formed from a single composition, or both concave and convex features, b) The first main surface of the second layer is treated with a coupling agent to bond the coupling agent to the second layer, wherein the first main surface of the second layer contains an inorganic material. c) Bringing the treated first main surface of the second layer into contact with a portion of the nanostructured first surface of the first layer, d) Bonding at least one of the first layer or the reaction products of the coupling agent to the second layer, thereby bonding the first layer and the second layer together via the coupling agent, wherein the coupling agent directly bonds the first main surface of the second layer to the nanostructured first surface of the first layer, or exists as a part of the coupling agent layer. Includes, The nanostructured first surface of the first layer and either the first main surface of the second layer or the coupling agent layer cooperate to define at least one void, A method comprising the first layer, the coupling agent bonded to the second layer, or both, comprising a partially cured material, wherein the partially cured material reacts to covalently bond the first layer and the second layer together.

14. The method according to any one of claims 11 to 13, wherein the processing comprises applying a coating of the coupling agent composition onto the first main surface of the second layer and drying the composition, and optionally the coupling agent composition comprises at least one of the coupling agent, a solvent, and a photoinitiator or a thermal initiator.

Images