Fluorine-free hydrophobic coating

Abstract

An optical article comprising a coating system that imparts anti-reflective properties and hydrophobic properties to the optical article. The coating system includes a hard coating layer on a lens substrate, and alternating layers of a low refractive index metal oxide and a high refractive index metal oxide deposited on the hard coating layer as an anti-reflective coating, or alternating layers of a medium refractive index metal oxide and a high refractive index metal oxide deposited on the hard coating layer as an anti-reflective coating. A fluorine-free hydrophobic coating composition is deposited on the anti-reflective coating to reduce the surface free energy of the anti-reflective surface of the optical article and to improve the overall cleaning performance of the lens surface by rendering the lens surface hydrophobic.

Description

Cross-references to related applications

[0001] This application claims priority to U.S. Provisional Application Serial No. 63 / 585,160 entitled “Fluorine-Free Hydrophobic Coating”, filed on September 25, 2023, the entire contents of which are incorporated herein by reference. Background Technology

[0002] Applying a functional coating (or multiple functional coatings) to the surface of an object can impart one or more properties or characteristics to that surface. One such property or characteristic includes imparting hydrophobicity to the surface. In other words, imparting hydrophobicity includes imparting waterproof or anti-fog properties to the surface. The development of hydrophobic surfaces has broad application prospects in many industries, including optical and non-optical fields.

[0003] The formation of hydrophobic surfaces on optical lenses has attracted widespread attention because water droplets on hydrophobic surfaces have a much higher wetting angle or contact angle, making the lenses less susceptible to wetting. Therefore, hydrophobic surfaces prevent the accumulation of tiny water droplets on the surface, avoiding a hazy appearance caused by light scattering.

[0004] In the optics industry, antireflective lens designs may include a lens substrate, a hard coating applied to the lens substrate, and alternating layers of high, medium, and low refractive index metal oxides applied to the hard coating to form an antireflective stack on the lens. However, due to the stickiness of the metal oxide surfaces and the high surface energy of the top surface of antireflective lenses, they can be difficult to clean. For example, simply wiping the lens surface with a cloth is insufficient for cleaning.

[0005] To address this issue, a hydrophobic coating is typically added on top of the anti-reflective coating stack to reduce the lens's high surface energy and adhesion, and to improve the lens's cleanability.

[0006] Currently, the hydrophobic coatings of optical lenses containing antireflective stacked structures are mainly fluoropolymer coatings. Fluoropolymers containing hydrophobic coatings can be coated on the top layer of the antireflective coating to enhance the hydrophobicity of the top layer, because such coatings can reduce the surface energy of the top layer, making it hydrophobic.

[0007] From a chemical mechanism perspective, these fluoropolymer hydrophobic coatings can utilize silane functional groups to bond with the metal / oxygen of the metal oxide layers in the antireflective coating stack structure. Besides silane functional groups, phosphonic acid groups (P=O and P-OH) in the fluoropolymer hydrophobic coatings can also achieve the same effect. Silane groups or P=O and P-OH functional groups form covalent or non-covalent bonds with the metals and oxygen in the various metal oxides of the antireflective stack structure in optical lenses.

[0008] However, the application of fluoropolymers as hydrophobic coatings poses serious health and environmental risks because these chemicals accumulate in the human body and environment and are difficult to degrade naturally, hence they are called "permanent chemicals".

[0009] Therefore, there is an urgent need to develop a fluorine-free hydrophobic coating that can impart hydrophobicity to the upper surface of the anti-reflective stacked structure of optical lenses. Summary of the Invention

[0010] This invention relates to systems, apparatuses, compositions, and methods for using fluorine-free compounds / compositions as hydrophobic coatings, which can be applied to antireflective coating stacks to reduce surface energy and improve the cleanability of lens surfaces.

[0011] In one embodiment, the antireflective lens may include a fluorine-free hydrophobic coating on its top surface. The antireflective lens includes a lens substrate. The lens substrate may be coated with a hard coating to improve its resistance to physical and environmental damage. The hard coating may be further coated with multiple layers of alternating high-refractive-index and low-refractive-index metal oxides of varying thicknesses to provide an antireflective stack structure. This antireflective stack structure may be coated with a fluorine-free hydrophobic coating to reduce the surface energy of the antireflective lens surface and improve cleanability.

[0012] In one embodiment, when the upper surface of the antireflective stack structure of the lens is coated with a fluorine-free hydrophobic coating, the contact angle between the upper surface of the antireflective lens and water / oil droplets can reach about 80°-90° or greater than about 100°, or about 105°-115°, or even more than about 150°.

[0013] In some embodiments, the fluorine-free hydrophobic coating composition may comprise any of the following compounds or any combination thereof: PDMS-grafted phosphonic acid, octadecylphosphonic acid, PDSM-grafted silane, and n-octadecylsilane, wherein the silane functional group may include trichlorosilane, trimethoxysilane, triethoxysilane, triisopropylsilane, or any other silane derivative capable of forming covalent or non-covalent bonds with the metal oxide layer in the antireflective stack structure; the polydimethylsiloxane (PDMS) portion in the PDMS-grafted phosphonic acid / PDSM-grafted silane may be a linear or branched siloxane.

[0014] In other embodiments, the fluorine-free hydrophobic coating composition may include another silicone component that contains both siloxane bonds (Si-O) and silicon-based bonds (Si-C), such as hexamethyldisiloxane (HMDSO).

[0015] In some instances, the fluorine-free hydrophobic coating of the above composition can be applied to the upper surface of the metal oxide layer of the antireflective stacked structure of the lens by various methods known in the art, such as using chip vacuum deposition, dip coating, spraying, or wiping the metal oxide surface with a chemical solution. Attached Figure Description

[0016] The following figures are used to illustrate certain exemplary aspects of this disclosure and should not be considered exclusive or limiting. The technical solutions protected by this disclosure can be modified, altered, combined, and transformed in various ways in form and function, which are readily achievable by those skilled in the art upon in conjunction with the teachings of this disclosure. References to the figures in this disclosure are as follows: Figure 1 This is a three-dimensional structural diagram of an anti-reflective lens in some embodiments of the present invention. The lens includes a lens substrate, a hard coating on the lens substrate, an anti-reflective stacked structure comprising a low refractive index layer and a high refractive index layer on the hard coating, and a hydrophobic coating deposited on top of the anti-reflective stacked structure.

[0017] Figure 2 This is a three-dimensional structural diagram of an anti-reflective lens in some embodiments of the present invention. The lens includes a lens substrate, a hard coating on the lens substrate, an anti-reflective stacked structure comprising a medium refractive index layer and a high refractive index layer on the hard coating, and a hydrophobic coating deposited on top of the anti-reflective stacked structure.

[0018] Figure 3 The contact angle and hydrophobicity persistence of surfaces coated with perfluorinated and polyfluoroalkyl substances (PFAS) and surfaces coated with the fluorine-free hydrophobic coating described in this application after friction are disclosed in some embodiments of the present invention.

[0019] Figure 4 This paper summarizes the experimental design of wetting contact angles (WCA) of the surface when coated with the fluorine-free hydrophobic hexamethyldisiloxane (HMDSO) of this application in some embodiments of the present invention.

[0020] Figures 5A-5C The variations of WCA of HMDSO with different process parameters in some embodiments of the present invention are disclosed. Figure 5A The variation of WCA of HMDSO with oxygen flow rate (sccm) in some embodiments of the present invention is disclosed. Figure 5B The variation of WCA of HMDSO with ion beam current (A) in some embodiments of the present invention is disclosed. Figure 5C The variation of WCA of HMDSO with HMDSO flow rate (sccm) in some embodiments of the present invention is disclosed.

[0021] Figure 6 The WCA measurement results of HMDSO after friction test and acetone cleaning test in some embodiments of the present invention are summarized. Detailed Implementation

[0022] Those skilled in the art will understand that this invention is not limited to the specific examples shown and described herein. Various modifications and variations can be made to this invention in conjunction with its teachings without departing from its scope, spirit, and purpose.

[0023] While different embodiments may be described in this specification, it is specifically envisioned that any features of different embodiments can be combined together in any combination. In other words, features of different embodiments can be mixed and matched with each other. Therefore, even if not all combinations of features are explicitly described in the specification, this disclosure is intended to cover any such combinations, especially those that can be understood and implemented by those skilled in the art.

[0024] The terminology used in this invention should be interpreted broadly and not restrictively. In the accompanying drawings, the same numbers refer to the same elements. Unless otherwise stated, all drawings are not to scale; the term "about" is defined as ±10% of the stated values.

[0025] Optical lenses may include a lens substrate. Non-limiting examples of lens substrates include glass, polymers, or other materials suitable for fabricating lens substrates. The lens substrate may be coated with a hard coating to improve its resistance to physical and environmental damage and enhance its strength and durability. The surface of the hard coating may be further coated with multiple layers of transparent material of alternating low-refractive-index and high-refractive-index metal oxides of varying thicknesses. Alternatively, the surface of the hard coating may be further coated with multiple layers of transparent material of alternating medium-refractive-index and high-refractive-index metal oxides. These alternating low-refractive-index and high-refractive-index or medium-refractive-index and high-refractive-index metal oxides reduce excessive reflected light from the lens surface, thereby forming an antireflective lens with an antireflective stack structure of metal oxides on the hard coating.

[0026] The surface of the anti-reflective stacked structure of the optical lens can be coated with a hydrophobic coating to reduce the overall surface energy of the lens; in some embodiments, the ideal hydrophobic coating is preferably a fluorine-free hydrophobic coating.

[0027] In some embodiments, the antireflective lens is an ophthalmic lens.

[0028] Figure 1One embodiment is shown in which a lens substrate 10 (e.g., an optical lens) may be coated with a hard coating 20 to provide the lens substrate with resistance to physical and environmental damage and to enhance its strength and durability. The surface of the hard coating 20 may be coated with a durable anti-reflective coating 30 to reduce reflections from the lens surface.

[0029] like Figure 1 As shown, the antireflective coating 30 comprises a multilayered stacked structure (e.g., 7 layers, more than 7 layers, or less than 7 layers) consisting of alternating L / H / L / H / L / H / L layers, wherein L may contain low-refractive-index layers (30a, 30c, 30e, 30g), and H may contain high-refractive-index layers (30b, 30d, 30f). A fluorine-free hydrophobic coating 40 is further coated on the outermost (final layer) 30g of the antireflective coating. However, in different embodiments, other layered structures may also be used, including reverse arrangements of the above structures.

[0030] In other embodiments, such as Figure 1 As shown, the antireflective stack structure 30 can employ, for example, fewer or more than seven alternating low-refractive-index layers and high-refractive-index layers. The number of alternating low-refractive-index and high-refractive-index layers is unlimited; any number of low-refractive-index and high-refractive-index layers can form the antireflective stack structure. In this respect, the stack structure can have 30n layers, where n equals the number of layers present.

[0031] The stacking order of the low-refractive-index layer (L) and the high-refractive-index layer (H) is not limited to... Figure 1 The diagram shows L / H / L / H / L / H / L. In some embodiments, the stacking order of the low refractive index layer (L) and the high refractive index layer (H) can be H / L / H / L / H / L / H. According to this stacking order, the surface of the hard coating layer 20 is coated with a high refractive index layer (H), and the outermost layer of the anti-reflective stack structure 30 can also be a high refractive index layer (H). Figure 2 One embodiment is shown in which a lens substrate 10 (e.g., an optical lens) may be coated with a hard coating 20 to provide the lens substrate with resistance to physical and environmental damage and to improve its strength and durability. The surface of the hard coating 20 may be coated with a durable anti-reflective coating 50 to reduce reflections on the lens surface.

[0032] like Figure 2 As shown, the antireflective coating 50 may comprise a multilayer stacked structure (e.g., 7 layers, more than 7 layers, or less than 7 layers) consisting of alternating M / H / M / H / M / H / M layers, wherein M may comprise medium refractive index layers (50a, 50c, 50e), and H may comprise high refractive index layers (50b, 50d, 50f). A fluorine-free hydrophobic coating 40 is further coated on the outermost layer 50g of the antireflective coating.

[0033] In other embodiments, the antireflective stack structure 50 may employ, for example, fewer or more than seven alternating intermediate and high refractive index layers. The number of alternating intermediate and high refractive index layers is not limited; any number of alternating intermediate and high refractive index layers can form the antireflective stack structure. In this respect, the stack structure may have 50n layers, where n equals the number of layers present.

[0034] The stacking order of the intermediate refractive index layer (M) and the high refractive index layer (H) is not limited to the following: Figure 2 The diagram shows M / H / M / H / M / H / M. In some embodiments, the stacking order of the intermediate refractive index layer (M) and the high refractive index layer (H) can be H / M / H / M / H / M / H. According to this stacking order, the surface of the hard coating layer 20 is coated with a high refractive index layer (H), and the outermost layer of the anti-reflective stack structure 50 can also be a high refractive index layer (H).

[0035] For clarity, the terms "high refractive index" or "high index" as used herein may include a refractive index greater than about 1.9 at a reference wavelength, for example, about 550 nm. "Low refractive index" or "low index" may include a refractive index less than about 1.55 at a reference wavelength, for example, about 550 nm. "Medium refractive index" or "medium index" may include a refractive index between about 1.55 and 1.9 at a reference wavelength, for example, about 550 nm.

[0036] In some embodiments, low-refractive-index materials may include, for example, silicon dioxide (SiO2) or any other metal oxide with a refractive index less than about 1.55 at a reference wavelength of about 550 nm. In some embodiments, medium-refractive-index materials may include aluminum oxide (Al2O3) or any other metal oxide with a refractive index of about 1.55 to 1.9 at a reference wavelength of about 550 nm. Materials suitable for high-refractive-index metal oxides may include various metal oxides such as titanium dioxide (TiO2), zirconium dioxide (ZrO2), niobium pentoxide (Nb2O5), tantalum pentoxide (Ta2O5), zinc oxide (ZnO2), indium oxide (In2O3), and hafnium oxide (HfO2), as well as any transition metal or non-transition metal oxide with a refractive index greater than 1.9 at a reference wavelength of about 550 nm.

[0037] The surface of metal oxides with anti-reflective stacked structures is usually hydrophilic. Due to the presence of metal cations and oxygen anions, they can interact with the protons, hydroxyl groups or polar groups of water / oil molecules, making the surface sticky. As a result, water / oil droplets spread on the surface, making it difficult to clean by wiping with a cloth.

[0038] Therefore, it is desirable to coat the surface of the top metal oxide layer of the antireflective stack structure with a hydrophobic coating so that the contact angle between the upper surface of the antireflective stack structure and water / oil droplets is greater than approximately 90°. Surfaces with a contact angle greater than approximately 90° are hydrophobic. On such surfaces, water / oil droplets tend to form beads rather than spread across the surface of the antireflective lens.

[0039] In some embodiments, when the upper surface of the antireflective stack structure is coated with a fluorine-free hydrophobic coating, the contact angle between the upper surface of the antireflective lens and water / oil droplets can be between about 80°-90°, or greater than about 100°, or about 105°-115°, or even greater than about 150°. The hydrophobic coating on the antireflective stack structure should have little or no effect on the reflective performance of the antireflective lens to minimize or eliminate cleaning problems caused by the hydrophilic surface of the antireflective stack.

[0040] The present invention provides one or more hydrophobic coatings containing fluorine-free components, thereby avoiding the use of fluorine-containing chemicals that may accumulate in the body or environment and are difficult to degrade.

[0041] In some embodiments, the hydrophobic coating may include a fluorine-free active component having functional groups that can form covalent or non-covalent bonds with the metal oxide layer of the antireflective stack structure. In some non-limiting examples, the functional groups of the fluorine-free active component may include non-limiting functional derivatives of organophosphonic acids and / or silanes.

[0042] In some embodiments, when the top layer of the antireflective coating 30 comprises a high refractive index layer (H) instead of a low refractive index layer (L), the metal oxide (such as...) in the top layer of the antireflective coating 30... Figure 1 The covalent or non-covalent bond strength (i.e. adhesion) between the active component (as shown) and the non-fluorinated active component containing organophosphonic acid and / or silane functional derivatives will be enhanced.

[0043] In other embodiments, when the top layer of the antireflective coating 50 comprises a high refractive index layer (H) instead of a medium refractive index layer (M), the covalent or non-covalent bond strength (i.e. adhesion) between the metal oxide in the top layer of the antireflective coating 50 and the fluorine-free active component containing a functional derivative of an organophosphonic acid and / or silane is enhanced.

[0044] In some embodiments, a thin high-refractive-index layer (H) may be used to enhance the covalent or non-covalent bonding between the metal oxide on the top layer of the antireflective coating 30 or 50 and the fluorine-free active component containing organophosphonic acid and / or silane functional derivatives. In some embodiments, the thickness of such a thin high-refractive-index layer (H) ranges from 0.1 nm to 150 nm. In other embodiments, the thickness of the thin high-refractive-index layer (H) ranges from 1 nm to 80 nm.

[0045] In some embodiments, the functional groups of the fluorine-free hydrophobic compound may include silicone polymers, such as silanes grafted with polydimethylsiloxane (PDMS), such as PDMS-grafted triethoxysilane and n-octadecylsilane.

[0046]

[0047] In PDMS-grafted silanes and n-octadecylsilanes, the silane functional groups can form covalent or non-covalent bonds with the metal oxide layer of the antireflective stack structure. Some non-limiting examples of silane functional groups include trichlorosilane, trimethoxysilane, triethoxysilane, triisopropylsilane, or any other silane derivative capable of forming covalent or non-covalent bonds with the metal oxide layer of the antireflective stack structure. In some embodiments, the polydimethylsiloxane (PDMS) portion of the PDMS-grafted silane may include a linear or branched siloxane.

[0048] In some embodiments, the fluorine-free hydrophobic coating may comprise a single compound, such as PDMS-grafted silane, or PDMS-grafted triethoxysilane. In other embodiments, the fluorine-free hydrophobic coating may comprise a composition of multiple compounds, such as a combination of PDMS-grafted silane and n-octadecylsilane. In some embodiments, the silane functional groups of the PDMS-grafted silane and n-octadecylsilane may include triethoxysilane. In such embodiments, the hydrophobic coating composition may comprise a combination of PDMS-grafted triethoxysilane and n-octadecyltriethoxysilane.

[0049] However, it should be understood that the combination of reagents is not limited to PDMS grafted with triethoxysilane and n-octadecyltriethoxysilane. Any other combination of silane functional groups in polydimethylsiloxane grafted with silane and / or n-octadecylsilane may also be used, including trichlorosilane, trimethoxysilane, triisopropoxysilane, or any other silane derivative capable of forming covalent or non-covalent bonds with the metal oxide layer in the antireflective stack structure. In some embodiments, polydimethylsiloxane grafted with silane and silane derivatives of n-octadecylsilane may be mixed in one or more combinations and coated onto the upper surface of the lens antireflective stack structure to improve the contact angle of water / oil droplets and enhance the durability, cleanability, and overall performance of the antireflective lens.

[0050] In some embodiments, the functional groups containing the fluorine-free hydrophobic compound may include phosphonic acid derivatives, such as polydimethylsiloxane (PDMS) grafted phosphonic acid and n-octadecylphosphonic acid.

[0051]

[0052] In PDMS-grafted phosphonic acid and n-octadecylphosphonic acid, the phosphonic acid functional groups can form covalent or non-covalent bonds with the metal oxide layer of the antireflective stack structure. In some embodiments, the polydimethylsiloxane (PDMS) portion in the PDMS-grafted phosphonic acid may include linear or branched siloxanes.

[0053] In some embodiments, the fluorine-free hydrophobic coating containing phosphonic acid derivatives may comprise a single compound, such as PDMS-grafted phosphonic acid, for example, linear or branched PDMS-grafted phosphonic acid. In other embodiments, the hydrophobic coating may be composed of a combination of multiple reagents, such as a combination of PDMS-grafted phosphonic acid and n-octadecylphosphonic acid.

[0054] In some embodiments, linear PDMS-grafted phosphonic acid and n-octadecylphosphonic acid can be combined to form a hydrophobic coating. In other embodiments, branched PDMS-grafted phosphonic acid and n-octadecylphosphonic acid can be combined to form a hydrophobic coating. In some embodiments, linear PDMS-grafted phosphonic acid, branched PDMS-grafted phosphonic acid, and n-octadecylphosphonic acid can be combined to form a hydrophobic coating. In some embodiments, polydimethylsiloxane-grafted phosphonic acid and n-octadecylphosphonic acid can be mixed and deposited on the upper surface of the lens antireflective stack structure to improve the contact angle of water / oil droplets and improve the durability, cleanability, and overall performance of the antireflective lens.

[0055] In some embodiments, the fluorine-free hydrophobic coating composition may comprise a combination of PDMS-grafted phosphonic acid and PDMS-grafted silane, wherein the silane functional groups of the PDMS-grafted silane may include trichlorosilane, trimethoxysilane, triethoxysilane, triisopropylsilane, or any other silane derivative capable of forming covalent or non-covalent bonds with the metal oxide layer of the antireflective stack structure, and the polydimethylsiloxane (PDMS) portion of the PDMS-grafted silane may include linear or branched siloxanes. In such embodiments, the phosphonic acid functional groups of the PDMS-grafted phosphonic acid may also form covalent or non-covalent bonds with the metal oxide layer of the antireflective stack structure, and its PDMS portion may include linear or branched siloxanes.

[0056] In other embodiments, the fluorine-free hydrophobic coating composition may include different combinations of PDMS-grafted phosphonic acid and n-octadecylsilane, wherein the silane functional group of the n-octadecylsilane may include trichlorosilane, trimethoxysilane, triethoxysilane, triisopropylsilane, or any other silane derivative capable of forming covalent or non-covalent bonds with the metal oxide layer of the antireflective stack structure, and the polydimethylsiloxane (PDMS) portion of the PDMS-grafted phosphonic acid may include linear or branched siloxanes.

[0057] In a further embodiment, the fluorine-free hydrophobic coating composition may include a combination of octadecylphosphonic acid and PDMS-grafted silane, wherein the silane functional groups of the PDMS-grafted silane may include trichlorosilane, trimethoxysilane, triethoxysilane, triisopropylsilane, or any other silane derivative capable of forming covalent or non-covalent bonds with the metal oxide layer of the antireflective stack structure, and the polydimethylsiloxane (PDMS) portion of the PDMS-grafted silane may include linear or branched siloxanes.

[0058] The fluorine-free hydrophobic coating composition may include different combinations of octadecylphosphonic acid and n-octadecylsilane, wherein the silane functional group of the n-octadecylsilane may include trichlorosilane, trimethoxysilane, triethoxysilane, triisopropylsilane, or any other silane derivative capable of forming covalent or non-covalent bonds with the metal oxide layer of the antireflective stack structure.

[0059] In other embodiments, the fluorine-free hydrophobic coating composition may include any compound or any possible combination of PDMS-grafted phosphonic acid, octadecylphosphonic acid, PDMS-grafted silane, and n-octadecylsilane, wherein the silane functional group may include trichlorosilane, trimethoxysilane, triethoxysilane, triisopropylsilane, or any other silane derivative capable of forming covalent or non-covalent bonds with the metal oxide layer of the antireflective stack structure, and the phosphonic acid functional group of the PDMS-grafted phosphonic acid may also form covalent or non-covalent bonds with the metal oxide layer of the antireflective stack structure. In such embodiments, the polydimethylsiloxane (PDMS) portion of the PDMS-grafted phosphonic acid or PDMS-grafted silane may include linear or branched siloxanes.

[0060] In other embodiments, such as Figure 2 As shown, when the antireflective stack structure comprises a medium-to-high refractive index metal oxide (M / H / M / H / M / H / M, etc.) covering a low refractive index metal oxide, the phosphonic acid functional groups of octadecylphosphonic acid and PDMS-grafted phosphonic acid can form stronger covalent or non-covalent bonds with the antireflective stack structure. In some embodiments, a suitable medium refractive index metal oxide may be aluminum oxide (Al2O3) or any other metal oxide with a refractive index of about 1.55 to 1.9 at a reference wavelength of about 550 nm. Examples of suitable high refractive index layers include titanium dioxide (TiO2), zirconium dioxide (ZrO2), niobium pentoxide (Nb2O5), tantalum pentoxide (Ta2O5), zinc oxide (ZnO2), indium oxide (In2O3), hafnium oxide (HfO2), and other transition or non-transition metal oxides with a refractive index greater than 1.9 at a reference wavelength of about 550 nm. In some embodiments, examples of low refractive index materials include, for example, silicon dioxide (SiO2) or other metal oxides with a refractive index of less than about 1.55 at a reference wavelength of about 550 nm. In other embodiments, such as Figure 2As shown, when the antireflective stack structure comprises a medium-to-high refractive index metal oxide (M / H / M / H / M / H / M, etc.) covering a low refractive index metal oxide, the PDMS-grafted silane and the silane functional groups of n-octadecylsilane can form stronger covalent or non-covalent bonds. In some embodiments, a suitable medium refractive index metal oxide may be aluminum oxide (Al2O3) or any other metal oxide with a refractive index of about 1.55 to 1.9 at a reference wavelength of about 550 nm. Examples of suitable high refractive index layers include titanium dioxide (TiO2), zirconium dioxide (ZrO2), niobium pentoxide (Nb2O5), tantalum pentoxide (Ta2O5), zinc oxide (ZnO2), indium oxide (In2O3), hafnium oxide (HfO2), and other transition or non-transition metal oxides with a refractive index greater than 1.9 at a reference wavelength of about 550 nm. In some embodiments, examples of low refractive index materials include, for example, silicon dioxide (SiO2) or other metal oxides with a refractive index of less than about 1.55 at a reference wavelength of about 550 nm.

[0061] In other embodiments, compared to using a low-refractive-index metal oxide (e.g., silicon dioxide, SiO2) as the top metal oxide layer of an antireflective stacking structure, the phosphonic acid functional groups of octadecylphosphonic acid and PDMS-grafted phosphonic acid can form stronger covalent and non-covalent bonds with medium-refractive-index metal oxides (e.g., aluminum oxide, Al2O3), such as... Figure 2 As shown.

[0062] It should be understood that the functional groups of the fluorine-free hydrophobic coating compounds are not limited to silicone polymers, such as PDMS-grafted silanes and n-octadecylsilanes and / or phosphonic acid derivatives, such as polydimethylsiloxane (PDMS)-grafted phosphonic acid and octadecylphosphonic acid. In some embodiments, the linking molecules and coupling agents may be selected based on the functional groups present in the silicone polymer or phosphonic acid derivative to improve the desired properties and processing conditions of the final hydrophobic coating material.

[0063] Non-limiting examples of linking molecules include isocyanates, such as, but not limited to, toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and hexamethylene diisocyanate (HDI); epoxy-containing molecules, such as, but not limited to, bisphenol A diglycidyl ether (BADGE); acid anhydrides and acid chlorides, such as, but not limited to, phthalic anhydride, succinic anhydride, and terephthaloyl chloride; azido or alkynyl-containing molecules, such as, but not limited to, azido-functionalized polymers and alkynyl-functionalized polymers; and aminosilanes, such as, but not limited to, γ-aminopropyltriethoxysilane (APTES).

[0064] In some embodiments, isocyanates may react with the hydroxyl, amino, or carboxyl groups of a fluorine-free hydrophobic coating compound to form urethane or urea bonds.

[0065] In some embodiments, epoxy-containing molecules can react with the amino, hydroxyl, and carboxyl groups of the fluorine-free hydrophobic coating compound to form strong covalent bonds.

[0066] In some embodiments, acid anhydrides and acid chlorides may react with the hydroxyl or amino groups of the fluorine-free hydrophobic coating to form ester or amide bonds.

[0067] In some embodiments, azido or alkynyl molecules can form triazole bonds with a fluorine-free hydrophobic coating via click chemistry.

[0068] In some embodiments, aminosilanes can be used as functional groups in fluorine-free hydrophobic coatings to modify surfaces and improve the adhesion between fluorine-free hydrophobic polymers and anti-reflective stacked inorganic fillers.

[0069] Non-limiting examples of coupling agents include silane coupling agents such as vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane (MPS), γ-glycidyl etheroxypropyltrimethoxysilane (GPS), and γ-aminopropyltriethoxysilane (APTES). Silane coupling agents can be used to bond inorganic materials (such as glass fibers) with organic polymers (such as fluorine-free hydrophobic polymers).

[0070] In vinyltrimethoxysilanes, the vinyl group (C=C) is attached to a silicon atom, which is then bonded to three methoxy groups (–OCH3). In vinyltrimethoxysilanes, the vinyl group can be used to bond with PDMS or alkyl functional groups in fluorine-free hydrophobic polymers via another reactive group.

[0071] In γ-aminopropyltriethoxysilane (APTES), a propyl group containing three carbon atoms is linked to an amino group (–NH2), one end of which is linked to a silicon atom, and the remaining arm of the silicon atom is linked to three ethoxy groups (–OCH2CH3).

[0072] In γ-aminopropyltriethoxysilane (APTES), the amino group can bind to PDMS or alkyl functional groups in a fluorine-free hydrophobic polymer via another reactive group.

[0073] In some embodiments, the above-mentioned fluorine-free hydrophobic coating can be applied to the surface of the top metal oxide layer of the lens antireflective stack structure by various methods in the prior art, such as using chip vacuum deposition, dip coating, spraying, or wiping the metal oxide surface with a chemical solution.

[0074] In some embodiments, in order to bond or interact with the antireflective stack structure, a fluorine-free hydrophobic compound / composition containing organophosphonic acid and / or silane functional groups can be vacuum deposited onto the upper surface of the metal oxide layer of the lens antireflective stack structure using a vacuum coater.

[0075] In some embodiments, PDMS grafted with triethoxysilane can be vacuum deposited on the upper surface of the metal oxide layer of the lens antireflective stack structure, such that the contact angle is in the range of 102.3 to 107.4.

[0076] In other embodiments, in order to bond or interact with the antireflective stack structure, a solution of a hydrophobic compound / composition containing organophosphonic acid and / or silane functional groups may be sprayed onto the upper surface of the metal oxide layer of the lens antireflective stack structure.

[0077] In some embodiments, in order to bond or interact with the antireflective stack structure, a hydrophobic compound / composition containing functional groups of organophosphonic acid and / or silane can be chemically wiped deposited on the upper surface of the metal oxide layer of the lens antireflective stack structure.

[0078] In some embodiments, the chemical wiping deposition of the fluorine-free hydrophobic compound / composition on the antireflective stack structure can be performed immediately after the antireflective stack structure is deposited on the hard coating of the lens substrate. In other embodiments, if chemical wiping deposition is not performed immediately after the antireflective stack structure deposition, it may be necessary to repeat the chemical wiping deposition of the fluorine-free hydrophobic coating. In some embodiments, the hydrophobic lens surface can be refreshed by wiping with a chemical solution containing PDMS-grafted silane (e.g., PDMS-grafted triethoxysilane). In other embodiments, an organosilicon component containing silicon-oxygen bonds (Si-O) and silicon-based bonds (Si-C) can be deposited as a fluorine-free hydrophobic coating on the metal oxide top surface of the lens antireflective stack structure.

[0079] In some embodiments, such silicon components containing both silicon-oxygen bonds and silicon-based bonds may include hexamethyldisiloxane (HMDSO). HMDSO can be deposited as a fluorine-free hydrophobic coating on the surface of the top metal oxide layer of an antireflective stack structure, giving it hydrophobic properties. HMDSO is an organosilicon dimer composed of silicon-oxygen bonds (Si-O) and methylsilyl groups (Si-CH3). x Group composition.

[0080] HMDSO possesses excellent properties that make it a potential hydrophobic coating, such as scratch resistance, corrosion resistance, water permeability barrier, and a low refractive index of approximately 1.4, which can contribute to improved efficiency. Furthermore, HMDSO has been reported to have contact angles of 100°–140°, which is an ideal characteristic for highly efficient hydrophobic coatings. The decomposition and deposition conditions of HMDSO can result in films with varying properties.

[0081] HMDSO can be deposited onto anti-reflective stacked structures using plasma technology, such as APCVD and PECVD. Plasma polymerization is a key process for forming a quartz-hard and highly hydrophobic coating.

[0082] In some embodiments, when the antireflective stack structure comprises low-refractive-index and high-refractive-index metal oxides (L / H / L / H / L / H / L, etc.), such as Figure 1 As shown, the siloxane and silyl groups in HMDSO can form covalent or non-covalent bonds with the metal oxide layers of the antireflective stacked structure.

[0083] In other embodiments, when the antireflective stack structure comprises medium and high refractive index metal oxides (M / H / M / H / M / H / M, etc.) covering low refractive index metal oxides, such as Figure 2 As shown, the covalent or non-covalent bonding ability of siloxanes and silyl groups in HMDSO with antireflective stacked structures is enhanced.

[0084] As shown in Table 1 and Figure 3 As shown, fluorine-free hydrophobic components containing organophosphonic acids and / or silane derivatives can be deposited on the upper surface of an antireflective stacked metal oxide layer, resulting in a water droplet contact angle of approximately 102° to 107°. This contact angle range is comparable to that of commercially available fluorinated hydrophobic coatings, such as perfluorinated and polyfluoroalkyl substances (PFAS).

[0085] In some embodiments, such as Figure 3 As shown in Table 1, the durability of fluorine-free hydrophobic coatings, such as those containing alkyl chains, is comparable to that of fluorine-containing hydrophobic PFAS coatings. Durability testing of such hydrophobic surfaces is performed by rubbing the coated surface. In some embodiments, the surface coated with the fluorine-free hydrophobic compound exhibits a contact angle of approximately 103° after approximately 2000 rubs. In other embodiments, the surface coated with the fluorine-free hydrophobic compound exhibits a contact angle of approximately 107° after approximately 500 rubs. It should be understood that a contact angle greater than 90° is characteristic of hydrophobic surfaces.

[0086] In some embodiments, such as Figure 3 As shown in Table 1, the abrasion resistance of fluorine-free hydrophobic coatings, such as those containing alkyl chains, is comparable to that of fluorine-containing hydrophobic coatings (PFAS).

[0087] In one embodiment, such as Figure 3 As shown in Table 1, the durability (2000 cycles) and abrasion resistance (A) of fluorine-free hydrophobic coatings, such as fluorine-free hydrophobic coatings containing alkyl chains, are comparable to those of fluorine-containing hydrophobic coatings or PFAS, such as PFAS material 1 [hydrophobic durability: 5000 cycles, abrasion resistance: UA] and PFAS material 2 [hydrophobic durability: 450 cycles, abrasion resistance: B].

[0088] Figure 3Table 1 further discloses that, in some other embodiments, the fluorine-free hydrophobic coating composition containing silicone components still has a contact angle of 102-107° after 10-40 rubs on the surface, which is a typical characteristic of hydrophobic surfaces.

[0089] In some embodiments, WCA experiments were performed, for example, on fluorine-free hydrophobic coatings containing hexamethyldisiloxane (HMDSO), where the wetted contact angle (WCA) can vary over a wide range depending on different process variables.

[0090] Figure 4 Table 2 summarizes the WCA experiments for surface-coated HMDSO. In some embodiments, the average WCA is obtained by averaging the measurements taken three times at different locations.

[0091] Depend on Figure 4 As shown in Table 2, the WCA obtained varies from 62±4° to 108±5° depending on parameters such as HMDSO flow rate, oxygen flow rate, ion current, neutral current, and ion beam pretreatment time (minutes). In some embodiments, when both HMDSO flow rate and oxygen flow rate are approximately 10 sccm, the ion current is approximately 1 A at 80 V, the neutral current is approximately 0.1 A, and the ion beam pretreatment time is approximately 2 minutes under the conditions of 80 V, 1 A, and 0.1 A, a WCA of approximately 108±5° is obtained.

[0092] Figure 5A The variation of WCA of HMDSO with oxygen flow rate (sccm) is disclosed. In some embodiments, obtaining a higher WCA, such as approximately 110°, requires optimizing the ratio of HMDSO flow rate to oxygen flow rate. In some embodiments, such as Figure 4 Table 2 and Figure 5A As shown, when the ratio of HMDSO flow rate to oxygen flow rate is approximately 1, a higher WCA of approximately 110° is obtained.

[0093] Figure 5B The variation of WCA of HMDSO with ion beam current (A) was disclosed. Figure 5B The curves disclosed show that higher WCA, such as approximately 100° for HMDSO, is sensitive to plasma conditions. In some embodiments, a WCA of approximately 100° for HMDSO can be obtained at an ion beam current of approximately 1.0 A.

[0094] Figure 5C The variation of WCA of HMDSO with HMDSO flow rate (sccm) is disclosed. In some embodiments, a higher WCA, such as about 100° WCA for HMDSO, can be obtained when the oxygen flow rate is about 10 sccm.

[0095] In some embodiments, the surface of the fluorine-free hydrophobic coating can be wiped with a coarse cotton cloth or cleaned with acetone to test the durability of the hydrophobic coating.

[0096] Figure 6 Table 3 summarizes the WCA measurement results of the HMDSO coated surface after coarse cotton cloth friction test and acetone cleaning test.

[0097] In some embodiments, the WCA of the HMDSO coated surface may decrease after abrasion or acetone cleaning. In some non-limiting examples, the decrease in abrasion tests ranges from 2° to 14°, and the decrease in acetone cleaning tests ranges from 3° to 5°.

[0098] Although the invention has been described with reference to specific embodiments and applications, those skilled in the art can make other embodiments or modifications based on these teachings without departing from the spirit or scope of the claimed invention. Therefore, it should be understood that these drawings and descriptions are provided as examples to facilitate understanding of the invention and should not be construed as limiting the scope of the invention.

Claims

1. A fluorine-free hydrophobic coating composition comprising one or more of the following compounds: PDMS grafted phosphonic acid, octadecylphosphonic acid, PDMS grafted silane, and / or n-octadecylsilane.

2. The fluorine-free hydrophobic coating composition according to claim 1, wherein one or more compounds selected from PDMS-grafted phosphonic acid, octadecylphosphonic acid, PDMS-grafted silane, and / or n-octadecylsilane are deposited on the antireflective stack structure of the optical article.

3. The fluorine-free hydrophobic coating composition according to claim 2, wherein the silane functional groups of PDMS grafted with silane or n-octadecylsilane and the phosphonic acid functional groups of PDMS grafted with phosphonic acid or octadecylphosphonic acid are configured to form bonds with the metal oxide layer of the antireflective stack structure.

4. The fluorine-free hydrophobic coating composition according to claim 2, wherein the anti-reflective stacking structure of the optical article comprises at least one high-refractive-index metal oxide layer and at least one low-refractive-index metal oxide layer.

5. The fluorine-free hydrophobic coating composition according to claim 2, wherein the anti-reflective stacking structure of the optical article comprises at least one high refractive index metal oxide layer and at least one medium refractive index metal oxide layer.

6. The fluorine-free hydrophobic coating composition according to claim 5, wherein the silane functional group of PDMS grafted with silane or n-octadecylsilane and the phosphonic acid functional group of PDMS grafted with phosphonic acid or octadecylphosphonic acid are configured to form an enhanced bond with an antireflective stack structure comprising a high-refractive-index metal oxide layer and a medium-refractive-index metal oxide layer.

7. The fluorine-free hydrophobic coating composition according to claim 3, wherein the silane functional group of the PDMS grafted silane or n-octadecylsilane includes trichlorosilane, trimethoxysilane, triethoxysilane or triisopropylsilane.

8. The fluorine-free hydrophobic coating composition according to claim 3, wherein the structure of PDMS grafted phosphonic acid or PDMS grafted silane includes linear PDMS or branched PDMS.

9. The fluorine-free hydrophobic coating composition according to claim 1, wherein the contact angle between the fluorine-free hydrophobic coating and the water droplet is greater than 90°.

10. The fluorine-free hydrophobic coating composition according to claim 1 further comprises a disilane.

11. The fluorine-free hydrophobic coating composition according to claim 10, wherein the disilane is hexamethyldisiloxane.

12. The fluorine-free hydrophobic coating composition according to claim 11, wherein the contact angle of the disilane comprising hexamethyldisiloxane is in the range of 100°-140°.

13. An anti-reflective optical article, comprising: Substrate; A hard coating deposited on the substrate; An anti-reflective layer deposited on the hard coating; as well as A fluorine-free hydrophobic coating composition deposited on the antireflective layer. The fluorine-free hydrophobic coating composition comprises at least one of PDMS-grafted silane, n-octadecylsilane, PDMS-grafted phosphonic acid, and / or octadecylphosphonic acid.

14. The fluorine-free hydrophobic coating composition according to claim 13, wherein the silane functional groups of PDMS grafted with silane and / or n-octadecylsilane, and the phosphonic functional groups of PDMS grafted with phosphonic acid or octadecylphosphonic acid, are configured to form bonds with the metal oxide layer of the antireflective stack structure.

15. The fluorine-free hydrophobic coating composition according to claim 13, wherein the silane functional groups of PDMS grafted with silane and / or n-octadecylsilane, and the phosphonic functional groups of PDMS grafted with phosphonic acid or octadecylphosphonic acid, are configured to form bonds with the linking molecule and the coupling agent to modulate the properties of the fluorine-free hydrophobic coating composition.

16. The fluorine-free hydrophobic coating composition according to claim 15, wherein the coupling agent for regulating the properties of the fluorine-free hydrophobic coating composition comprises a silane coupling agent, said silane coupling agent comprising vinyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane (MPS), γ-glycidyl etheroxypropyltrimethoxysilane (GPS), or γ-aminopropyltriethoxysilane (APTES).

17. The fluorine-free hydrophobic coating composition according to claim 15, wherein the linking molecules used to regulate the properties of the fluorine-free hydrophobic coating composition include isocyanates, epoxy-containing molecules, acid anhydrides, acid chlorides, azides, alkynyl groups, or aminosilanes.

18. A method for coating a fluorine-free hydrophobic layer on an anti-reflective stacked structure of optical lenses, comprising: Apply a hard coating to the lens substrate; Deposit an anti-reflective stacked structure on a hard coating; as well as A fluorine-free hydrophobic coating is applied to the upper surface of the anti-reflective stacked structure to form a fluorine-free hydrophobic layer on the upper surface of the optical lens.

19. The method of claim 18, wherein providing a fluorine-free hydrophobic layer on the upper surface of the anti-reflective stack structure further comprises performing the process by using chip vacuum deposition, dip coating, spray coating, or wiping the upper surface of the metal oxide with a solution containing a hydrophobic coating.

20. The method of claim 18, wherein forming a fluorine-free hydrophobic coating on the upper surface of the antireflective stack structure further comprises depositing at least one component selected from PDMS-grafted phosphonic acid, octadecylphosphonic acid, PDMS-grafted silane, or n-octadecylsilane.

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