WO2017029624A1 - Spectacle lens optic with superhydrophobic superoleophobic surface - Google Patents

Spectacle lens optic with superhydrophobic superoleophobic surface Download PDF

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Publication number
WO2017029624A1
WO2017029624A1 PCT/IB2016/054934 IB2016054934W WO2017029624A1 WO 2017029624 A1 WO2017029624 A1 WO 2017029624A1 IB 2016054934 W IB2016054934 W IB 2016054934W WO 2017029624 A1 WO2017029624 A1 WO 2017029624A1
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WO
WIPO (PCT)
Prior art keywords
microstructures
spectacle lens
lens optic
coating
optic
Prior art date
Application number
PCT/IB2016/054934
Other languages
French (fr)
Inventor
Amitava Gupta
Torn PRACHARKTAM
Venkatramani S. Iyer
Original Assignee
Thai Optical Group Public Company Limited
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Filing date
Publication date
Application filed by Thai Optical Group Public Company Limited filed Critical Thai Optical Group Public Company Limited
Publication of WO2017029624A1 publication Critical patent/WO2017029624A1/en

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Classifications

    • GPHYSICS
    • G02OPTICS
    • G02CSPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
    • G02C7/00Optical parts
    • G02C7/02Lenses; Lens systems ; Methods of designing lenses
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C17/00Surface treatment of glass, not in the form of fibres or filaments, by coating
    • C03C17/02Surface treatment of glass, not in the form of fibres or filaments, by coating with glass
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C15/00Surface treatment of glass, not in the form of fibres or filaments, by etching
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C17/00Surface treatment of glass, not in the form of fibres or filaments, by coating
    • C03C17/28Surface treatment of glass, not in the form of fibres or filaments, by coating with organic material
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/14Protective coatings, e.g. hard coatings
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/18Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2217/00Coatings on glass
    • C03C2217/20Materials for coating a single layer on glass
    • C03C2217/28Other inorganic materials
    • C03C2217/284Halides
    • C03C2217/285Fluorides
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2217/00Coatings on glass
    • C03C2217/70Properties of coatings
    • C03C2217/76Hydrophobic and oleophobic coatings

Definitions

  • the present disclosure relates generally to spectacle lens optics and, more particularly, to spectacle lens optics with superhydrophobic and superoleophobic surfaces.
  • Optical components suffer degraded performance when contaminated by water or other liquids.
  • spectacle lens optics are less effective when contaminated by liquids such as water, oil, lipids, or other lipohilic fluids.
  • Surfaces that do not readily retain liquids would have many benefits, such as greater visual comfort and user friendliness by remaining clean during normal indoor and outdoor use and having improved cleanability.
  • wettability i.e., the ability of the liquid to maintain contact with the surface.
  • a high degree of wetting typically results in the liquid being retained on the surface, while a low degree of wetting results in the liquid not being readily retained on the surface.
  • a fluid with large wetting is shown in Figure 6(a), while a fluid with less wetting is shown in Figure 6(b).
  • Adhesive forces between the liquid and the surface can cause a liquid drop to spread across the surface, as shown in Figure 6(a). Cohesive forces within the liquid cause the liquid drop to ball up and avoid contact with the surface, as shown in Figure 6(b).
  • the contact angle ( ⁇ ) is the angle at which the liquid-vapor interface meets the surface-liquid interface. The contact angle is determined by the result between adhesive and cohesive forces. The contact angle decreases as the liquid drop spreads over the surface. Thus, the contact angle provides an inverse measure of wettability.
  • a nonwettable surface is considered hydrophobic.
  • Superhydrophobic surfaces have contact angles greater than 150°, having very little contact between the liquid drop and the surface.
  • a nonwettable surface is considered oleophobic.
  • Superoleophobic surfaces can have contact angles greater than 120°, with glycerol or a hydrocarbon, such as n- Hexane.
  • the lotus leaf is an example of a naturally occurring superhydrophobic surface.
  • a lotus leaf exhibits a water contact angle of 140° to 150°.
  • the superhydrophobic nature of the lotus leaf causes water dropped on its surface to bead up and slide off easily, maintaining a dry surface even at low tilt angles.
  • the underside of the lotus leaf exhibits superoleophobicity and superhydrophobicity, even when immersed in water.
  • the water contact angle of a surface that is coated with pre-existing generally available hydrophobic materials is in the range of 100° to 120°.
  • preexisting generally available hydrophobic materials exhibit hydrophobic properties that are inferior to the lotus leaf, indicating an opportunity for improved hydrophobic materials.
  • the Wenzel model describes the homogeneous wetting regime, in which liquid fills in gaps or grooves in the surface, i.e., there is complete wetting of the rough surface by the liquid.
  • the contact angle can be increased through surface roughness, but it is limited so as to not achieve more desired hydrophobic and oleophobic properties.
  • the heterogeneous wetting regime allows for achieving more desired hydrophobic and oleophobic properties.
  • the surface is a composite surface of patches of air and the solid surface.
  • the Cassie-Baxter model describes the heterogeneous wetting regime having air-liquid interfaces formed by air pockets trapped in valleys between peaks of the rough surface. These air pockets can further increase the apparent contact angle between the liquid and the surface.
  • the heterogeneous wetting regime is subject to disturbances in equilibrium due to external factors, which can result in transition from the Cassie-Baxter state to the Wenzel state.
  • the Cassie-Baxter model does not account for surfaces that include a plurality of periodic microstructures disposed or formed on the surface with a ratio of the height of the microstructures to the periodicity of the microstructures greater than 1.18. At ratios in excess of this value, the Cassie-Baxter model predicts that the air-liquid interface that traps the air in the valleys will fail, producing a fully wetted surface (the Wenzel state) and losing the benefit to the contact angle produced by the trapped air in the valleys. In other words, the Cassie-Baxter model predicts a maximum in the reduction of the wetting of a rough surface at a height to periodicity ratio of 1.18 or less. [0012] Thus, the current efforts to achieve superhydrophobic and superoleophobic surfaces through use of surface roughness, are not sufficient.
  • Embodiments of this disclosure relate generally to articles with a
  • the embodiments relate to a spectacle lens optic that has a surface that includes a periodic microstructure producing superhydrophobic and superoleophobic behavior.
  • a spectacle lens optic is provided.
  • the spectacle lens optic includes a surface having a water contact angle of more than 150°, measured at room temperature and atmospheric pressure by the sessile drop method, and a glycerol contact angle of more than 120°, measured under the same conditions.
  • a water droplet slides off the surface of the optic when the surface is tilted by an angle of 10° or less from horizontal.
  • the surface of the optic may have a hysteresis in contact angles of advancing and receding drops of less than 10°.
  • the spectacle lens optic may include plurality of periodic surface microstructures.
  • a height of the microstructures is at least 1.8 times greater than a periodicity of the microstructures, preferably the height is at least twice the periodicity of the microstructures.
  • the microstructures have a minimum height of about 100 nanometers and a maximum height of about 25 microns, such as about 5 microns to about 10 microns.
  • the spectacle lens optic may further include a surface coating.
  • the surface coating may have a thickness in the range of about 10 nanometers to about 1,000 nanometers, such as about 100 nm to about 250 nm.
  • the spectacle lens optic may further include a perfluorocarbon polymer coating.
  • the perfluorocarbon polymer coating may be cross linked.
  • the perfluorocarbon coating may have a refractive index of 1.40 or less at 530 nm, as measured at room temperature, and a water contact angle of at least 90° when applied to a smooth surface.
  • the perfluorocarbon coating has a thickness in the range of about 50 nanometers to about 250 nanometers.
  • the spectacle lens optic may further include a hard coating layer or an
  • the spectacle lens optic may include glass or plastic, such as polycarbonate of bisphenol A, diethyl glycol diacrylate, allyl diglycol carbonate, epoxides, polyurethanes, polyureas, polyesters, polycarbonates, polyurea-urethanes, or polymethyl methacrylate.
  • glass or plastic such as polycarbonate of bisphenol A, diethyl glycol diacrylate, allyl diglycol carbonate, epoxides, polyurethanes, polyureas, polyesters, polycarbonates, polyurea-urethanes, or polymethyl methacrylate.
  • a method of producing a spectacle lens optic includes creating a plurality of periodic micro structures on a surface of a spectacle lens optic, and disposing a perfluorocarbon polymer coating over the microstructures.
  • a height of the microstructures is at least 1.8 times greater than a periodicity of the microstructures.
  • Creating the microstructures may include a precision diamond machining process or an etching process.
  • the etching process may utilize a mask, and include exposure of the spectacle lens optic to ultraviolet radiation.
  • the disposing of the perfluorocarbon polymer coating may include a chemical vapor deposition process or a plasma enhanced chemical vapor deposition process.
  • the disposing of the perfluorocarbon polymer coating does not alter the microstructures.
  • the disposing of the perfluorocarbon polymer coating may utilize perfluorocarbon molecules as a precursor, or may utilize a precursor that includes a fluorosilane, such as S1 2 F6, S13F8, S1 4 F 1 0, S1 2 F 4 H 2 , or mixtures thereof.
  • the maximum temperature of deposition may be 150°C or less.
  • FIG. 1 is a photomicrograph of water drops on a lotus leaf.
  • FIGS. 2(a) and 2(b) are schematic representations of wetting of a rough surface by a fluid according to the Wenzel model and the Cassie-Baxter model, respectively.
  • FIG. 3 is a schematic representation of a liquid droplet and a microstructured surface according to one embodiment.
  • FIG. 4(a) is schematic representation of a cross-section of a periodic
  • FIG. 4(b) is a schematic representation of a perspective view of a plurality of periodic microstructures.
  • FIG. 4(c) is a schematic representation of a top-down view of a surface including a plurality of periodic microstructures of the type shown in FIG. 4(a).
  • FIG. 4(d) is a schematic representation of a top-down view of a surface including a plurality of concentric periodic microstructures.
  • FIGS. 5(a) and 5(b) are photomicrographs of micromachined surfaces produced utilizing single point diamond turning.
  • FIGS. 6(a) and 6(b) illustrate a fluid with large wetting and with less wetting, respectively.
  • Embodiments described and depicted herein relate generally to a spectacle lens optic with a superhydrophobic and superoleophobic surface.
  • a super hydrophobic, superoleophobic surface of a spectacle lens provides substantial advantages in visual comfort and user friendliness by remaining clean during routine outdoor and indoor use. Additionally, the cleanability of the surface is improved.
  • the surface composition described herein increases the contact angle of the surface for all fluids, including water and other hydrophilic liquids as well as oil, lipids and other lipophilic fluids. Contact angles with water in excess of 150° and with glycerol in excess of 120°, each in contact with air, can be achieved.
  • the process of producing the surface composition is applicable to plastic as well as glass surfaces, such as the anterior (outward facing) surface, posterior surface, or both of a spectacle lens optic. The process may be readily integrated with conventional fabrication processes of spectacle lens optics, and allow production of antireflective as well as superhydrophobic, superoleophobic surfaces.
  • a superhydrophobic surface is defined as a surface with a water contact angle of 150° or more.
  • a superhydrophobic surface may allow for a tilt angle necessary to slide a liquid drop off of the surface of less than 10° from horizontal.
  • a superoleophobic surface is defined as surface that has a contact angle of more than 120° with glycerol or a hydrocarbon, such as n-Hexane.
  • a surface structure that produces superhydrophobic and superoleophobic surface wetting characteristics may be produced by combining a plurality of periodic microstructures on a surface in combination with a surface coating on the microstructures.
  • the surface coating is preferably a hydrophobic polymer.
  • the hydrophobic polymer coating allows the ratio of the height of the periodic microstructures to the periodicity of the microstructures to be extended to 1.8 and more, producing an increased surface roughness while also maintaining an air-liquid interface over the valleys between the peaks in the rough surface (the Cassie-Baxter state). As shown in Figure 3, the air trapped in the valleys between the peaks of the rough surface reduces the total contact area of the surface with the liquid drop despite the increased height to periodicity ratio of the microstructures.
  • a spectacle lens optic surface may be treated with the periodic microstructures and the surface coating.
  • the surface to be treated may be glass or plastic.
  • Exemplary surfaces may include polycarbonate of bisphenol A, diethyl glycol diacrylate, allyl diglycol carbonate, epoxides, polyurethanes, polyureas, polyesters, polycarbonates, polyurea- urethanes, or polymethyl methacrylate.
  • the surface treated with the microstructures may have any appropriate geometry, such as a flat, convex or concave shape.
  • a microstructure refers to a geometrical component that includes at least one dimension in the range of less than 1,000 microns. As shown in Figure 4(a), each microstructure 100 can include regularly spaced peaks 1 10. The geometry of the microstructures may be characterized, for example, as sinusoidal, square wave, saw tooth or cone-like, with the apex of each cone pointing upwards. A microstructure having a square wave geometry is shown in Figure 4(a).
  • the microstructures may have a width (w) in the range of about 100 nm to about 25 microns.
  • the width (w) of the microstructures is shown in Figure 4(c).
  • the height (h) of the microstructures which is characterized as the height of the peaks in the microstructures, may be at least 1.8 times the periodicity (p) of the microstructures, such as at least twice the periodicity of the microstructures.
  • the height (h) of the microstructures is shown in Figure 4(a).
  • the periodicity (p) as utilized herein refers to the distance between peaks of the microstructure, as shown in Figure 4(a).
  • the height of the microstructures may preferably be in the range of about 100 nm to about 25 microns, such as about 5 microns to about 10 microns.
  • the periodicity of the microstructures may be in the range of about 50 nm to about 12 microns.
  • a preferred range of the height of the microstructures is about 5 microns to about 25 microns, with a correlating preferred periodicity of about 2 microns to about 12 microns.
  • the root mean square roughness of the surface containing the plurality of microstructures may be at least about 100 nm and less than about 20 microns.
  • the plurality of microstructures on the surface may be separated by a portion of the surface having a height approximately equivalent to, or equivalent to, the minimum height of the microstructures between peaks.
  • the distance (d) between the microstructures may be in the same range as the periodicity of the microstructures, and may have the same relationship to the height of the microstructures as the periodicity of the microstructures.
  • the distance (d) between the microstructures is shown in Figure 4(c).
  • the height of the microstructures may be at least 1.8 times the distance between the
  • microstructures such as at least twice the distance between the microstructures.
  • the adjacent microstructures 100 may be out of phase with each other, such that the peaks 110 of the adjacent microstructures are not aligned.
  • the microstructures 100 may be geometrically straight lines and arranged in a parallel relationship on the surface 120, as shown in Figure 4(c).
  • a cross-section of a single microstructure 100 shown in Figure 4(c) along line A-A' is shown in Figure 4(a).
  • the plurality of microstructures may also be considered to form a two-dimensional array of discrete peaks on the surface 120.
  • the microstructures 100 may be in the form of rings and arranged concentrically on the surface 120, as shown in Figure 4(d).
  • Additional nanostructures such as nanotubes or nanoparticles, may also be included on the surface of the microstructures to further increase the root mean square roughness of the surface.
  • the microstructures may be formed by any appropriate technique. Exemplary techniques for the formation of the microstructures include solvent etching, laser etching, precision machining, compression molding, transfer molding, or combinations thereof.
  • the microstructures may be formed by removing or shaping portions of the surface of the article, which may be formed from plastic or glass.
  • the microstructures may be formed by a precision machining process, such as a diamond turning process. A fine tool, with a diameter in the range of 10 microns to 50 microns, and tip radius in the range of 1 micron to 5 microns may be employed in the turning process.
  • the speed of rotation of the part to be turned may be maintained in the range of 1000 Hz to 10,000 Hz, while the tool is moved to cut the surface and produce the microstructures.
  • a series of grooves formed in a surface using a single fluted tool and sharp tool radius are shown in Figures 5(a) and 5(b).
  • the precision machining process may also be employed to remove material from the surface between the microstructures, producing a plurality microstructures with the desired geometry and spacing.
  • the microstructures may also be formed by etching the lens material, such as by solvent or laser etching.
  • a plastic surface may be etched with a radiation process that employs a mask, such as an ultraviolet (UV) radiation process.
  • the mask may be a thin glass plate with a thickness of 25 microns to 50 microns that is doped to absorb UV radiation at a specific wavelength range that causes rapid degradation of the plastic surface.
  • the glass plate may be etched using lithographic techniques, to form channels that correspond to the desired geometry of the microstructure.
  • the glass plate may then be tightly attached to the plastic surface to be etched, and the combined workpiece immersed in a fluid, such as a fluid that matches the refractive index of the glass plate at the wavelength of the UV radiation to be employed for the etching process.
  • a fluid such as a fluid that matches the refractive index of the glass plate at the wavelength of the UV radiation to be employed for the etching process.
  • the fluid is preferably transparent to the UV radiation, and dissolves the degraded photoproduct created by the UV radiation in the plastic.
  • the UV radiation source is then turned on, and the UV radiation is transmitted through the channel in the glass plate to be incident on the plastic substrate.
  • the degraded photoproduct created by the UV radiation in the plastic is then dissolved by the fluid.
  • the etching process may result in minimal polymer chain unzipping processes, so that the lateral spreading of the etching process beyond the desired geometry is minimized.
  • the use of an index or refraction matching fluid further minimizes scattering losses at the edges of the channels.
  • the surface coating disposed on the surface of the microstructures further enhances the hydrophobic characteristics thereof, and may also positively affect the oleophobic characteristics of the surface.
  • the surface coating may be a hydrophobic, low surface energy layer with a water contact angle of at least 90° when applied to a smooth surface.
  • the surface coating may have a thickness in the range of about 10 nm to about 1,000 nm, such as about 50 nm to about 250 nm, or about 100 nm to about 200 nm.
  • the surface coating may substantially uniformly, or uniformly, cover the microstructures and the surface on which the microstructures are disposed.
  • the surface coating may modify the surface energy of the spectacle lens optic when containing several atomic monolayers, such as greater than about 5 atomic monolayers. Each atomic monolayer of the surface coating may have a thickness of about 1 nm to about 5 nm.
  • the thickness of the surface coating may be selected based on a desired impact on the optical properties of the spectacle lens optic.
  • the effect of the surface coating on the optical properties, such as reflectance and absorbance, of the spectacle lens optic may be minimal when the surface coating has a thickness that is less than about 10% of the wavelength of the incident light.
  • a surface coating with a thickness of less than about 50 nm may alter the surface energy of the spectacle lens optic while having a minimal effect on the optical properties thereof.
  • a surface coating with a thickness of about 20 nm or about 25 nm may be employed to alter the surface energy of the spectacle lens optic while having a minimal effect on the optical properties thereof.
  • the thickness of the surface coating may be selected to modify the optical properties of the spectacle lens optic.
  • the surface coating may have a thickness selected to modify the reflectance of the spectacle lens optic, and in some embodiments may act as an anti-reflectance coating.
  • a surface coating modifying the reflectance of the spectacle lens optic may have a thickness of about 100 nm to about 250 nm, such as about 100 nm to about 200 nm.
  • the thickness of the surface coating may alternatively be selected to significantly alter the optical properties of the spectacle lens optic, such that the optical properties of the spectacle lens optic are dominated by the optical properties of the surface coating.
  • a surface coating with a thickness of greater than about 500 nm may dominate the optical properties of the spectacle lens optic.
  • a surface coating with the desired hydrophobic properties may be formed from a perfluorocarbon based polymer.
  • a surface coating based on a (CF x ) n species may be employed.
  • a surface coating based on CH x F y may be employed.
  • the perfluorocarbon based polymer coating may be cross linked.
  • the surface coating may be selected to substantially maintain the optical properties of the surface on which it is disposed.
  • the surface coating may have a refractive index of 1.40 or less at 530 nm as measured at room temperature.
  • the surface coating is preferably the outermost coating present on the surface.
  • the surface coating may be disposed directly on the microstructures or on other optional coatings that are disposed on the microstructures.
  • the surface coating is selected such that it may be deposited on the
  • the material selected to form the surface coating may be selected such that a vapor deposition process may be employed to dispose the surface coating over the microstructures to avoid excessive force application to the microstructures that may be produced in contact deposition processes. Additionally, the material selected to form the surface coating may be selected such that the deposition process may be carried out below a softening temperature of the material that forms the microstructures, such as a maximum deposition temperature of less than about 150°C.
  • the surface coating such as a perfluorocarbon based polymer coating, may be deposited over the microstructures by any appropriate technique that does not alter the geometry of the microstructures.
  • the deposition process may have a maximum temperature of deposition of less than a softening temperature of the material that forms the
  • microstructures such as about 150°C or less. Limiting the temperature of the deposition process may avoid the undesired temperature induced degradation of the microstructure geometry.
  • the method of deposition may be selected to avoid physical contact with the microstructures during the deposition process that could result in deformation or fracture of the microstructures. For example, an atmospheric plasma technique or a chemical vapor deposition method may be employed.
  • the atmospheric plasma formed by a mixture of oxygen and helium may be fed with a stream of a surface coating precursor, such as a fluorocarbon precursor, mixed with Helium to maintain a proper vapor balance.
  • a surface coating precursor such as a fluorocarbon precursor
  • the resulting deposition rate depends directly on the atom density of silicon in the precursor, and may be controlled by the temperature of the precursor gas streams fed into the plasma.
  • the atom density, and hence the rate of deposition may vary with the molecular weight, boiling point, and vapor pressure of the precursor molecule, as well as the enthalpy of bond scission in the precursor molecule.
  • Chemical vapor deposition may also be utilized to form the surface coating on the microstructures.
  • the CVD technique may be employed to deposit a perfluorocarbon film on a plastic or coated plastic surface on which the microstructures are formed.
  • a preferred process is a plasma enhanced chemical vapor deposition (PECVD) process, in which a plasma is employed to lower the required substrate temperature when performing the CVD process.
  • PECVD plasma enhanced chemical vapor deposition
  • Any appropriate fluorocarbon precursors may be employed to produce a perfluorocarbon based polymer coating, such as perfluorocarbon molecules.
  • the precursors may include one or more of C 2 F6, C 4 F 1 0, C 2 F 4 H 2 , and C3F6, each of which has bond energies in the range of 3000 kJ/M to 5800 kJ/M.
  • the presence of hydrogen in C 2 F 4 H 2 makes it especially suitable as a precursor, since HF may be readily removed from the system.
  • a fluorosilane may be utilized as the precursor, such as Si 2 F 6 , S1 3 F 8 , S1 4 F 10 , S1 2 F 4 H 2 , or mixtures thereof.
  • Additional coatings may be disposed between the microstructures and the surface coating, such that the hydrophobic surface coating forms the outermost surface.
  • additional coatings may be, for example, antireflective coatings or hard coatings, such as those commonly employed on spectral lens optics for the purposes of reducing reflections and providing scratch resistance, respectively.
  • the microstructures may be deposited on the surface of the article, such as by selectively depositing a perfluorocarbon based polymer with the desired periodic microstructure geometry. Selective deposition of perfluorocarbon based polymer microstructures may be accomplished by transfer molding, chemical vapor deposition or plasma polymerization. An additional hydrophobic or oleophobic surface coating is not required when the microstructures are formed from a hydrophobic polymer material, such as the perfluorocarbon based polymer materials discussed herein.
  • a preferred method to characterize the performance of the treated surfaces is to measure the contact angle of liquid on the surface using a sessile drop. Both advancing and receding contact angles may be measured, with the hysteresis between these two values indicating the degree of attachment of the drop to the surface.
  • the surfaces described herein preferably exhibit hysteresis in contact angles of advancing and receding drops of less than 10°.
  • a tilt angle required to slide a drop off of a planar surface is representative of the force of attachment of the drop to the surface.
  • the surfaces described herein preferably exhibit a tilt angle of less than 10° from horizontal.
  • the surfaces including the microstructures described herein coated with a perfluorocarbon based polymer coating layer also develop anti-reflective properties, enhancing transmission of light through the optic.

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  • Surface Treatment Of Optical Elements (AREA)

Abstract

A spectacle lens optic with a superhydrophobic and superoleophobic surface. The surface includes a plurality of periodic microstructures and a perfluorocarbon based polymer coating disposed thereon. The method of producing the spectacle lens optic includes mechanical formation of the periodic microstructures on the surface and subsequent vapor deposition of the perfluorocarbon based polymer coating.

Description

SPECTACLE LENS OPTIC WITH SUPERHYDROPHOBIC
SUPEROLEOPHOBIC SURFACE
BACKGROUND
[0001] The present disclosure relates generally to spectacle lens optics and, more particularly, to spectacle lens optics with superhydrophobic and superoleophobic surfaces.
[0002] Optical components suffer degraded performance when contaminated by water or other liquids. For example, spectacle lens optics are less effective when contaminated by liquids such as water, oil, lipids, or other lipohilic fluids. Surfaces that do not readily retain liquids would have many benefits, such as greater visual comfort and user friendliness by remaining clean during normal indoor and outdoor use and having improved cleanability.
[0003] Whether a surface will readily retain liquid, such as water or oils, can be determined by wettability, i.e., the ability of the liquid to maintain contact with the surface. A high degree of wetting typically results in the liquid being retained on the surface, while a low degree of wetting results in the liquid not being readily retained on the surface. A fluid with large wetting is shown in Figure 6(a), while a fluid with less wetting is shown in Figure 6(b).
[0004] Adhesive forces between the liquid and the surface can cause a liquid drop to spread across the surface, as shown in Figure 6(a). Cohesive forces within the liquid cause the liquid drop to ball up and avoid contact with the surface, as shown in Figure 6(b). As shown in Figure 6(b), the contact angle (Θ) is the angle at which the liquid-vapor interface meets the surface-liquid interface. The contact angle is determined by the result between adhesive and cohesive forces. The contact angle decreases as the liquid drop spreads over the surface. Thus, the contact angle provides an inverse measure of wettability.
[0005] For water, a nonwettable surface is considered hydrophobic. Superhydrophobic surfaces have contact angles greater than 150°, having very little contact between the liquid drop and the surface.
[0006] For oil, a nonwettable surface is considered oleophobic. Superoleophobic surfaces can have contact angles greater than 120°, with glycerol or a hydrocarbon, such as n- Hexane. [0007] The lotus leaf is an example of a naturally occurring superhydrophobic surface. A lotus leaf exhibits a water contact angle of 140° to 150°. As shown in Figure 1, the superhydrophobic nature of the lotus leaf causes water dropped on its surface to bead up and slide off easily, maintaining a dry surface even at low tilt angles. The underside of the lotus leaf exhibits superoleophobicity and superhydrophobicity, even when immersed in water.
[0008] In contrast, the water contact angle of a surface that is coated with pre-existing generally available hydrophobic materials is in the range of 100° to 120°. Thus, preexisting generally available hydrophobic materials exhibit hydrophobic properties that are inferior to the lotus leaf, indicating an opportunity for improved hydrophobic materials.
[0009] One approach to increasing the hydrophobicity and oleophobicity of a surface is to increase the roughness of the surface. As shown in Figure 2(a), the Wenzel model describes the homogeneous wetting regime, in which liquid fills in gaps or grooves in the surface, i.e., there is complete wetting of the rough surface by the liquid. In this homogeneous wetting regime, the contact angle can be increased through surface roughness, but it is limited so as to not achieve more desired hydrophobic and oleophobic properties.
[0010] The heterogeneous wetting regime allows for achieving more desired hydrophobic and oleophobic properties. In the heterogeneous wetting regime, the surface is a composite surface of patches of air and the solid surface. As shown in Figure 2(b), the Cassie-Baxter model describes the heterogeneous wetting regime having air-liquid interfaces formed by air pockets trapped in valleys between peaks of the rough surface. These air pockets can further increase the apparent contact angle between the liquid and the surface. However, the heterogeneous wetting regime is subject to disturbances in equilibrium due to external factors, which can result in transition from the Cassie-Baxter state to the Wenzel state.
[0011] Moreover, the Cassie-Baxter model does not account for surfaces that include a plurality of periodic microstructures disposed or formed on the surface with a ratio of the height of the microstructures to the periodicity of the microstructures greater than 1.18. At ratios in excess of this value, the Cassie-Baxter model predicts that the air-liquid interface that traps the air in the valleys will fail, producing a fully wetted surface (the Wenzel state) and losing the benefit to the contact angle produced by the trapped air in the valleys. In other words, the Cassie-Baxter model predicts a maximum in the reduction of the wetting of a rough surface at a height to periodicity ratio of 1.18 or less. [0012] Thus, the current efforts to achieve superhydrophobic and superoleophobic surfaces through use of surface roughness, are not sufficient.
SUMMARY OF THE INVENTION
[0013] Embodiments of this disclosure relate generally to articles with a
superhydrophobic and superoleophobic surface. More specifically, the embodiments relate to a spectacle lens optic that has a surface that includes a periodic microstructure producing superhydrophobic and superoleophobic behavior.
[0014] A spectacle lens optic is provided. The spectacle lens optic includes a surface having a water contact angle of more than 150°, measured at room temperature and atmospheric pressure by the sessile drop method, and a glycerol contact angle of more than 120°, measured under the same conditions. A water droplet slides off the surface of the optic when the surface is tilted by an angle of 10° or less from horizontal. The surface of the optic may have a hysteresis in contact angles of advancing and receding drops of less than 10°.
[0015] The spectacle lens optic may include plurality of periodic surface microstructures. A height of the microstructures is at least 1.8 times greater than a periodicity of the microstructures, preferably the height is at least twice the periodicity of the microstructures. The microstructures have a minimum height of about 100 nanometers and a maximum height of about 25 microns, such as about 5 microns to about 10 microns.
[0016] The spectacle lens optic may further include a surface coating. The surface coating may have a thickness in the range of about 10 nanometers to about 1,000 nanometers, such as about 100 nm to about 250 nm. For example, the spectacle lens optic may further include a perfluorocarbon polymer coating. The perfluorocarbon polymer coating may be cross linked. The perfluorocarbon coating may have a refractive index of 1.40 or less at 530 nm, as measured at room temperature, and a water contact angle of at least 90° when applied to a smooth surface. The perfluorocarbon coating has a thickness in the range of about 50 nanometers to about 250 nanometers.
[0017] The spectacle lens optic may further include a hard coating layer or an
antireflective coating. The spectacle lens optic may include glass or plastic, such as polycarbonate of bisphenol A, diethyl glycol diacrylate, allyl diglycol carbonate, epoxides, polyurethanes, polyureas, polyesters, polycarbonates, polyurea-urethanes, or polymethyl methacrylate.
[0018] A method of producing a spectacle lens optic is provided. The method includes creating a plurality of periodic micro structures on a surface of a spectacle lens optic, and disposing a perfluorocarbon polymer coating over the microstructures. A height of the microstructures is at least 1.8 times greater than a periodicity of the microstructures.
[0019] Creating the microstructures may include a precision diamond machining process or an etching process. The etching process may utilize a mask, and include exposure of the spectacle lens optic to ultraviolet radiation.
[0020] The disposing of the perfluorocarbon polymer coating may include a chemical vapor deposition process or a plasma enhanced chemical vapor deposition process. The disposing of the perfluorocarbon polymer coating does not alter the microstructures. The disposing of the perfluorocarbon polymer coating may utilize perfluorocarbon molecules as a precursor, or may utilize a precursor that includes a fluorosilane, such as S12F6, S13F8, S14F10, S12F4H2, or mixtures thereof. The maximum temperature of deposition may be 150°C or less.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] References are made to the accompanying drawings that form a part of this disclosure, and which illustrate the embodiments in which the systems and methods described in this specification can be practiced.
[0022] FIG. 1 is a photomicrograph of water drops on a lotus leaf.
[0023] FIGS. 2(a) and 2(b) are schematic representations of wetting of a rough surface by a fluid according to the Wenzel model and the Cassie-Baxter model, respectively.
[0024] FIG. 3 is a schematic representation of a liquid droplet and a microstructured surface according to one embodiment.
[0025] FIG. 4(a) is schematic representation of a cross-section of a periodic
microstructure.
[0026] FIG. 4(b) is a schematic representation of a perspective view of a plurality of periodic microstructures. [0027] FIG. 4(c) is a schematic representation of a top-down view of a surface including a plurality of periodic microstructures of the type shown in FIG. 4(a).
[0028] FIG. 4(d) is a schematic representation of a top-down view of a surface including a plurality of concentric periodic microstructures.
[0029] FIGS. 5(a) and 5(b) are photomicrographs of micromachined surfaces produced utilizing single point diamond turning.
[0030] FIGS. 6(a) and 6(b) illustrate a fluid with large wetting and with less wetting, respectively.
DETAILED DESCRIPTION
[0031] Embodiments described and depicted herein relate generally to a spectacle lens optic with a superhydrophobic and superoleophobic surface.
[0032] A super hydrophobic, superoleophobic surface of a spectacle lens provides substantial advantages in visual comfort and user friendliness by remaining clean during routine outdoor and indoor use. Additionally, the cleanability of the surface is improved.
[0033] The surface composition described herein increases the contact angle of the surface for all fluids, including water and other hydrophilic liquids as well as oil, lipids and other lipophilic fluids. Contact angles with water in excess of 150° and with glycerol in excess of 120°, each in contact with air, can be achieved. The process of producing the surface composition is applicable to plastic as well as glass surfaces, such as the anterior (outward facing) surface, posterior surface, or both of a spectacle lens optic. The process may be readily integrated with conventional fabrication processes of spectacle lens optics, and allow production of antireflective as well as superhydrophobic, superoleophobic surfaces.
[0034] A superhydrophobic surface, as utilized herein, is defined as a surface with a water contact angle of 150° or more. A superhydrophobic surface may allow for a tilt angle necessary to slide a liquid drop off of the surface of less than 10° from horizontal.
[0035] A superoleophobic surface, as utilized herein, is defined as surface that has a contact angle of more than 120° with glycerol or a hydrocarbon, such as n-Hexane.
[0036] It has been determined that a surface structure that produces superhydrophobic and superoleophobic surface wetting characteristics may be produced by combining a plurality of periodic microstructures on a surface in combination with a surface coating on the microstructures. The surface coating is preferably a hydrophobic polymer. The hydrophobic polymer coating allows the ratio of the height of the periodic microstructures to the periodicity of the microstructures to be extended to 1.8 and more, producing an increased surface roughness while also maintaining an air-liquid interface over the valleys between the peaks in the rough surface (the Cassie-Baxter state). As shown in Figure 3, the air trapped in the valleys between the peaks of the rough surface reduces the total contact area of the surface with the liquid drop despite the increased height to periodicity ratio of the microstructures.
The Spectacle Lens Optic
[0037] A spectacle lens optic surface may be treated with the periodic microstructures and the surface coating. The surface to be treated may be glass or plastic. Exemplary surfaces may include polycarbonate of bisphenol A, diethyl glycol diacrylate, allyl diglycol carbonate, epoxides, polyurethanes, polyureas, polyesters, polycarbonates, polyurea- urethanes, or polymethyl methacrylate. The surface treated with the microstructures may have any appropriate geometry, such as a flat, convex or concave shape.
The Microstructure
[0038] As utilized herein, a microstructure refers to a geometrical component that includes at least one dimension in the range of less than 1,000 microns. As shown in Figure 4(a), each microstructure 100 can include regularly spaced peaks 1 10. The geometry of the microstructures may be characterized, for example, as sinusoidal, square wave, saw tooth or cone-like, with the apex of each cone pointing upwards. A microstructure having a square wave geometry is shown in Figure 4(a).
[0039] The microstructures may have a width (w) in the range of about 100 nm to about 25 microns. The width (w) of the microstructures is shown in Figure 4(c). The height (h) of the microstructures, which is characterized as the height of the peaks in the microstructures, may be at least 1.8 times the periodicity (p) of the microstructures, such as at least twice the periodicity of the microstructures. The height (h) of the microstructures is shown in Figure 4(a). The periodicity (p) as utilized herein refers to the distance between peaks of the microstructure, as shown in Figure 4(a). The height of the microstructures may preferably be in the range of about 100 nm to about 25 microns, such as about 5 microns to about 10 microns. The periodicity of the microstructures may be in the range of about 50 nm to about 12 microns. A preferred range of the height of the microstructures is about 5 microns to about 25 microns, with a correlating preferred periodicity of about 2 microns to about 12 microns. The root mean square roughness of the surface containing the plurality of microstructures may be at least about 100 nm and less than about 20 microns.
[0040] The plurality of microstructures on the surface may be separated by a portion of the surface having a height approximately equivalent to, or equivalent to, the minimum height of the microstructures between peaks. The distance (d) between the microstructures may be in the same range as the periodicity of the microstructures, and may have the same relationship to the height of the microstructures as the periodicity of the microstructures. The distance (d) between the microstructures is shown in Figure 4(c). For example, the height of the microstructures may be at least 1.8 times the distance between the
microstructures, such as at least twice the distance between the microstructures. As shown in Figure 4(b), the adjacent microstructures 100 may be out of phase with each other, such that the peaks 110 of the adjacent microstructures are not aligned. The microstructures 100 may be geometrically straight lines and arranged in a parallel relationship on the surface 120, as shown in Figure 4(c). A cross-section of a single microstructure 100 shown in Figure 4(c) along line A-A' is shown in Figure 4(a). Thus, the plurality of microstructures may also be considered to form a two-dimensional array of discrete peaks on the surface 120. Alternatively, the microstructures 100 may be in the form of rings and arranged concentrically on the surface 120, as shown in Figure 4(d).
[0041] Additional nanostructures, such as nanotubes or nanoparticles, may also be included on the surface of the microstructures to further increase the root mean square roughness of the surface.
Forming the Microstructure
[0042] The microstructures may be formed by any appropriate technique. Exemplary techniques for the formation of the microstructures include solvent etching, laser etching, precision machining, compression molding, transfer molding, or combinations thereof. The microstructures may be formed by removing or shaping portions of the surface of the article, which may be formed from plastic or glass. [0043] The microstructures may be formed by a precision machining process, such as a diamond turning process. A fine tool, with a diameter in the range of 10 microns to 50 microns, and tip radius in the range of 1 micron to 5 microns may be employed in the turning process. The speed of rotation of the part to be turned may be maintained in the range of 1000 Hz to 10,000 Hz, while the tool is moved to cut the surface and produce the microstructures. A series of grooves formed in a surface using a single fluted tool and sharp tool radius are shown in Figures 5(a) and 5(b). The precision machining process may also be employed to remove material from the surface between the microstructures, producing a plurality microstructures with the desired geometry and spacing.
[0044] The microstructures may also be formed by etching the lens material, such as by solvent or laser etching. A plastic surface may be etched with a radiation process that employs a mask, such as an ultraviolet (UV) radiation process. The mask may be a thin glass plate with a thickness of 25 microns to 50 microns that is doped to absorb UV radiation at a specific wavelength range that causes rapid degradation of the plastic surface. The glass plate may be etched using lithographic techniques, to form channels that correspond to the desired geometry of the microstructure. The glass plate may then be tightly attached to the plastic surface to be etched, and the combined workpiece immersed in a fluid, such as a fluid that matches the refractive index of the glass plate at the wavelength of the UV radiation to be employed for the etching process. The fluid is preferably transparent to the UV radiation, and dissolves the degraded photoproduct created by the UV radiation in the plastic. The UV radiation source is then turned on, and the UV radiation is transmitted through the channel in the glass plate to be incident on the plastic substrate. The degraded photoproduct created by the UV radiation in the plastic is then dissolved by the fluid. The etching process may result in minimal polymer chain unzipping processes, so that the lateral spreading of the etching process beyond the desired geometry is minimized. The use of an index or refraction matching fluid further minimizes scattering losses at the edges of the channels. Alternatively, a mask may be deposited on the surface to be etched. Lithographic techniques may be employed to etch a glass surface in a similar manner.
The Coating
[0045] The surface coating disposed on the surface of the microstructures further enhances the hydrophobic characteristics thereof, and may also positively affect the oleophobic characteristics of the surface. The surface coating may be a hydrophobic, low surface energy layer with a water contact angle of at least 90° when applied to a smooth surface. The surface coating may have a thickness in the range of about 10 nm to about 1,000 nm, such as about 50 nm to about 250 nm, or about 100 nm to about 200 nm. The surface coating may substantially uniformly, or uniformly, cover the microstructures and the surface on which the microstructures are disposed. The surface coating may modify the surface energy of the spectacle lens optic when containing several atomic monolayers, such as greater than about 5 atomic monolayers. Each atomic monolayer of the surface coating may have a thickness of about 1 nm to about 5 nm.
[0046] The thickness of the surface coating may be selected based on a desired impact on the optical properties of the spectacle lens optic. The effect of the surface coating on the optical properties, such as reflectance and absorbance, of the spectacle lens optic may be minimal when the surface coating has a thickness that is less than about 10% of the wavelength of the incident light. Thus, for the visible light spectrum, a surface coating with a thickness of less than about 50 nm may alter the surface energy of the spectacle lens optic while having a minimal effect on the optical properties thereof. In some embodiments, a surface coating with a thickness of about 20 nm or about 25 nm may be employed to alter the surface energy of the spectacle lens optic while having a minimal effect on the optical properties thereof.
[0047] The thickness of the surface coating may be selected to modify the optical properties of the spectacle lens optic. The surface coating may have a thickness selected to modify the reflectance of the spectacle lens optic, and in some embodiments may act as an anti-reflectance coating. A surface coating modifying the reflectance of the spectacle lens optic may have a thickness of about 100 nm to about 250 nm, such as about 100 nm to about 200 nm. The thickness of the surface coating may alternatively be selected to significantly alter the optical properties of the spectacle lens optic, such that the optical properties of the spectacle lens optic are dominated by the optical properties of the surface coating. A surface coating with a thickness of greater than about 500 nm may dominate the optical properties of the spectacle lens optic.
[0048] A surface coating with the desired hydrophobic properties may be formed from a perfluorocarbon based polymer. According to one embodiment, a surface coating based on a (CFx)n species may be employed. Alternatively, a surface coating based on CHxFy may be employed. The perfluorocarbon based polymer coating may be cross linked.
[0049] The surface coating may be selected to substantially maintain the optical properties of the surface on which it is disposed. For example, the surface coating may have a refractive index of 1.40 or less at 530 nm as measured at room temperature.
[0050] The surface coating is preferably the outermost coating present on the surface. The surface coating may be disposed directly on the microstructures or on other optional coatings that are disposed on the microstructures.
[0051] The surface coating is selected such that it may be deposited on the
microstructures without altering the geometry of the microstructures. The material selected to form the surface coating may be selected such that a vapor deposition process may be employed to dispose the surface coating over the microstructures to avoid excessive force application to the microstructures that may be produced in contact deposition processes. Additionally, the material selected to form the surface coating may be selected such that the deposition process may be carried out below a softening temperature of the material that forms the microstructures, such as a maximum deposition temperature of less than about 150°C.
Depositing the Coating
[0052] The surface coating, such as a perfluorocarbon based polymer coating, may be deposited over the microstructures by any appropriate technique that does not alter the geometry of the microstructures. The deposition process may have a maximum temperature of deposition of less than a softening temperature of the material that forms the
microstructures, such as about 150°C or less. Limiting the temperature of the deposition process may avoid the undesired temperature induced degradation of the microstructure geometry. The method of deposition may be selected to avoid physical contact with the microstructures during the deposition process that could result in deformation or fracture of the microstructures. For example, an atmospheric plasma technique or a chemical vapor deposition method may be employed.
[0053] In an atmospheric plasma technique, the atmospheric plasma formed by a mixture of oxygen and helium may be fed with a stream of a surface coating precursor, such as a fluorocarbon precursor, mixed with Helium to maintain a proper vapor balance. The resulting deposition rate depends directly on the atom density of silicon in the precursor, and may be controlled by the temperature of the precursor gas streams fed into the plasma. The atom density, and hence the rate of deposition, may vary with the molecular weight, boiling point, and vapor pressure of the precursor molecule, as well as the enthalpy of bond scission in the precursor molecule.
[0054] Chemical vapor deposition (CVD) may also be utilized to form the surface coating on the microstructures. The CVD technique may be employed to deposit a perfluorocarbon film on a plastic or coated plastic surface on which the microstructures are formed. A preferred process is a plasma enhanced chemical vapor deposition (PECVD) process, in which a plasma is employed to lower the required substrate temperature when performing the CVD process.
[0055] Any appropriate fluorocarbon precursors may be employed to produce a perfluorocarbon based polymer coating, such as perfluorocarbon molecules. The precursors may include one or more of C2F6, C4F10, C2F4H2, and C3F6, each of which has bond energies in the range of 3000 kJ/M to 5800 kJ/M. The presence of hydrogen in C2F4H2 makes it especially suitable as a precursor, since HF may be readily removed from the system.
Alternatively, a fluorosilane may be utilized as the precursor, such as Si2F6, S13F8, S14F10, S12F4H2, or mixtures thereof.
Additional Coatings
[0056] Additional coatings may be disposed between the microstructures and the surface coating, such that the hydrophobic surface coating forms the outermost surface. These additional coatings may be, for example, antireflective coatings or hard coatings, such as those commonly employed on spectral lens optics for the purposes of reducing reflections and providing scratch resistance, respectively.
Alternative for Forming the Microstructure
[0057] According to an alternative embodiment, the microstructures may be deposited on the surface of the article, such as by selectively depositing a perfluorocarbon based polymer with the desired periodic microstructure geometry. Selective deposition of perfluorocarbon based polymer microstructures may be accomplished by transfer molding, chemical vapor deposition or plasma polymerization. An additional hydrophobic or oleophobic surface coating is not required when the microstructures are formed from a hydrophobic polymer material, such as the perfluorocarbon based polymer materials discussed herein.
Characterizing Performance
[0058] A preferred method to characterize the performance of the treated surfaces is to measure the contact angle of liquid on the surface using a sessile drop. Both advancing and receding contact angles may be measured, with the hysteresis between these two values indicating the degree of attachment of the drop to the surface. The surfaces described herein preferably exhibit hysteresis in contact angles of advancing and receding drops of less than 10°.
[0059] Similarly, a tilt angle required to slide a drop off of a planar surface is representative of the force of attachment of the drop to the surface. The surfaces described herein preferably exhibit a tilt angle of less than 10° from horizontal.
[0060] The surfaces including the microstructures described herein coated with a perfluorocarbon based polymer coating layer also develop anti-reflective properties, enhancing transmission of light through the optic. The superhydrophobic and
superoleophobic properties of the surfaces described herein render the surfaces more easily cleanable, which reduces the forces necessary to clean the surface and effectively renders the surface more scratch resistant.
[0061] While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular inventions. Certain features described in this specification in the context of separate implementations can also be implemented in combination in a single
implementation. Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Claims

WHAT IS CLAIMED IS:
1. A spectacle lens optic, comprising a surface having a water contact angle of more than 150°, measured by the sessile drop method at room temperature and atmospheric pressure, and a glycerol contact angle of more than 120°, measured under the same conditions.
2. The spectacle lens optic of claim 1, wherein a water droplet slides off the surface of the optic when the surface is tilted by an angle of 10° or less from horizontal.
3. The spectacle lens optic of claim 1, wherein the surface of the optic has a hysteresis in contact angles of advancing and receding drops of less than 10°.
4. The spectacle lens optic of claim 1, wherein the optic comprises a plurality of periodic surface microstructures.
5. The spectacle lens optic of claim 4, wherein a height of the microstructures is at least 1.8 times greater than a periodicity of the microstructures.
6. The spectacle lens optic of claim 4, wherein the microstructures have a minimum height of about 100 nanometers and a maximum height of about 25 microns.
7. The spectacle lens optic of claim 4, wherein the microstructures have a height in the range of about 5 microns to about 10 microns.
8. The spectacle lens optic of claim 1, further comprising a perfluorocarbon polymer coating.
9. The spectacle lens optic of claim 8, wherein the perfluorocarbon polymer coating is cross linked.
10. The spectacle lens optic of claim 8, wherein the perfluorocarbon coating has a refractive index of 1.40 or less at 530 nm, as measured at room temperature.
11. The spectacle lens optic of claim 8, wherein the perfluorocarbon coating has a water contact angle of at least 90° when applied to a smooth surface.
12. The spectacle lens optic of claim 8, wherein the perfluorocarbon coating has a thickness in the range of about 50 nanometers to about 250 nanometers.
13. The spectacle lens optic of claim 1, further comprising a surface coating having a thickness in the range of about 10 nanometers to about 1,000 nanometers.
14. The spectacle lens optic of claim 13, wherein the surface coating has a thickness in the range of about 100 nm to about 250 nm.
15. The spectacle lens optic of claim 1, further comprising a hard coating layer.
16. The spectacle lens optic of claim 1, further comprising an antireflective coating.
17. The spectacle lens optic of claim 1, comprising plastic or glass.
18. The spectacle lens optic of claims 1, comprising polycarbonate of bisphenol A, diethyl glycol diacrylate, allyl diglycol carbonate, epoxides, polyurethanes, polyureas, polyesters, polycarbonates, polyurea-urethanes, or polymethyl methacrylate.
19. A spectacle lens optic surface comprising: a plurality of periodic microstructures; and a perflurocarbon coating disposed over the microstructures, wherein a height of the microstructures is at least 1.8 times greater than the periodicity of the microstructures.
20. The method of claim 19, wherein the spectacle lens optic comprises polycarbonate of bisphenol A, diethyl glycol diacrylate, allyl diglycol carbonate, epoxides, polyurethanes, polyureas, polyesters, polycarbonates, polyurea-urethanes, or polymethyl methacrylate.
21. The spectacle lens of claim 19, wherein a height of the microstructures is at least twice the periodicity of the microstructures.
22. A method, comprising: creating a plurality of periodic microstructures on a surface of a spectacle lens optic; and disposing a perfluorocarbon polymer coating over the microstructures; wherein a height of the microstructures is at least 1.8 times greater than a periodicity of the microstructures.
23. The method of claim 22, wherein disposing the perfluorocarbon polymer coating does not alter the microstructures.
24. The method of claim 22, wherein creating the microstructures comprises a precision diamond machining process.
25. The method of claim 22, wherein creating the microstructures comprises an etching process.
26. The method of claim 25, wherein the etching process utilizes a mask.
27. The method of claim 25, wherein the etching process comprises exposure of the spectacle lens optic to ultraviolet radiation.
28. The method of claim 22, wherein disposing the perfluorocarbon polymer coating comprises a chemical vapor deposition process.
29. The method of claim 22, wherein disposing the perfluorocarbon polymer coating comprises a plasma enhanced chemical vapor deposition process.
30. The method of claim 22, wherein disposing the perfluorocarbon polymer coating utilizes perfluorocarbon molecules as a precursor.
31. The method of claim 29, wherein the precursor comprises S12F6, S13F8, S14F10, S12F4H2, or mixtures thereof.
32. The method of claim 29, wherein the precursor comprises a fluorosilane.
33. The method of claim 22, wherein disposing the perfluorocarbon polymer coating comprises a maximum temperature of deposition of 150°C or less.
34. The method of claim 22, wherein the spectacle lens optic comprises polycarbonate of bisphenol A, diethyl glycol diacrylate, allyl diglycol carbonate, epoxides, polyurethanes, polyureas, polyesters, polycarbonates, polyurea-urethanes, or polymethyl methacrylate.
PCT/IB2016/054934 2015-08-18 2016-08-17 Spectacle lens optic with superhydrophobic superoleophobic surface WO2017029624A1 (en)

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