Two-phase anti-icing coating for vehicle sensors and vehicle body components

Abstract

An anti-icing coating having a continuous phase and a discrete phase. The continuous phase includes a fluorine-containing polymer formed from a fluorine-containing precursor having a functionality greater than 2. The discrete phase includes a plurality of domains having a fluoride-free hygroscopic and / or hydrophilic material. The plurality of domains are dispersed within and immersible in the continuous phase. At least a portion of the fluorine-free material is bonded to the fluorine-containing polymer via an isocyanate-containing moiety. The fluorine-containing polymer is crosslinked with a crosslinking molecule having at least four functional groups. The fluorine-free material is poly (ethylene glycol).

Description

Technical Field

[0001] The present disclosure relates to coatings for exterior vehicle surfaces, and more particularly to anti-icing coatings for exterior vehicle sensors and body components. Background Art

[0002] Modern vehicles, especially partially or fully autonomous vehicles, are equipped with external sensors to collect information about the vehicle's surroundings. Radio detection and ranging (RADAR), light detection and ranging (LiDAR), ultrasonic, and cameras represent the majority of external sensors used in the automotive industry. These external sensors are typically mounted on external surfaces or recesses defined in the vehicle's exterior panels. The external surfaces of vehicle sensors and vehicle components are formed from a variety of materials, including plastics, metals, sensors, glass, and painted surfaces, which are susceptible to the harsh external operating environment of the vehicle.

[0003] Road debris, including dirt, dust, solvents (including oil and fuel), and water, sleet, ice, and snow in freezing conditions, can accumulate on the exterior surfaces of sensors and components. This accumulation not only affects the aesthetics of the sensors and components, but can also affect the performance of these sensors and operating surfaces. Particularly in operating environments with subfreezing temperatures, ice, sleet, and snow may accumulate on the exterior surfaces of these sensors, potentially affecting the operation of these sensors as well as removable exterior components such as the fuel door, charging port, hood, and trunk lid.

[0004] Sensors and exterior surfaces of vehicle components have been coated with anti-debris coatings. However, known anti-debris coatings have limited effectiveness against icing and have a limited effective life that can be prematurely shortened by solvents (such as oils and fuels) that may contaminate the anti-debris coating surface. Thus, while known anti-debris coatings achieve their intended purpose, there remains a need for an improved or new coating that has improved anti-icing capabilities, solvent resistance, and is able to withstand the harsh operating environment of a vehicle. Summary of the invention

[0005] According to several aspects, an anti-icing coating is disclosed, the anti-icing coating having a continuous phase including a first material and a plurality of domains including a second material. The plurality of domains are dispersed within the continuous phase and can be immersed in the continuous phase. One of the first material and the second material includes a fluorine-containing polymer formed from a fluorine-containing precursor having a functionality greater than 2. The other of the first material and the second material includes a fluorine-free hygroscopic or hydrophilic material. At least a portion of the fluorine-free material is bonded to the fluorine-containing polymer through an isocyanate-containing portion. The fluorine-containing polymer is cross-linked with a cross-linking molecule having at least 4 functional groups, the functional groups including nitrogen-containing portions, oxygen-containing portions, and combinations thereof.

[0006] In another aspect of the present disclosure, the first material is a fluorine-containing polymer and the second material is a fluorine-free material.

[0007] In another aspect of the present disclosure, the fluorine-free material includes at least one of poly(acrylic acid), poly(ethylene glycol), poly(2-hydroxyethyl methacrylate), poly(vinylimidazole), poly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline), poly(vinylpyrrolidone), and a modified cellulose polymer, wherein the modified cellulose polymer includes at least one of carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and methyl cellulose.

[0008] In another aspect of the present disclosure, the fluorine-free material is poly(ethylene glycol).

[0009] In another aspect of the present disclosure, the fluorine-containing polymer includes at least one of fluorinated polyols, perfluorocarbons, perfluoropolyethers, polyfluoroacrylates, polyfluorosilicones, polyvinylidene fluoride, polytrifluoroethylene, polytetrafluoroethylene, and copolymers thereof.

[0010] In another aspect of the present disclosure, the fluorine-containing precursor includes at least one of a hydroxyl group and an amine functional group.

[0011] In another aspect of the present disclosure, the fluorine-containing precursor is polytetrafluoroethylene having a plurality of pendant hydroxyl groups.

[0012] In another aspect of the present disclosure, the anti-icing coating further comprises at least one ionic substance selected from the group consisting of (2,2-bis-(1-(1-methylimidazolium)-methylpropane-1,3-diol bromide), 1,2-bis(2'-hydroxyethyl)imidazolium bromide, (3-hydroxy-2-(hydroxymethyl)-2-methylpropyl)-3-methyl-1H-3λ4-imidazol-1-ium bromide, 2,2-bis(hydroxymethyl)butanoic acid, N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid, N-methyl-2,2'-iminodiethanol, 3-dimethylamino-1,2-propanediol, 2,2-bis(hydroxymethyl)propionic acid, 1,4-bis(2-hydroxyethyl)piperazine, 2,6-diaminohexanoic acid, N,N-bis(2-hydroxyethyl)glycine, 2-hydroxypropionic acid hemi-calcium salt, dihydroxymethylpropionic acid, N-methyldiethanolamine, N-ethyldiethanolamine, N-propyldiethanolamine, N-benzyldiethanolamine, N-tert-butyldiethanolamine, bis(2-hydroxyethyl)benzylamine and bis(2-hydroxypropyl)aniline.

[0013] In another aspect of the present disclosure, the anti-icing coating further comprises at least one ionic species that is polymerized simultaneously from the isocyanate-containing moiety, the fluorine-containing polymer, and the fluorine-free material, such that the at least one ionic species is located between the fluorine-containing polymer and the fluorine-free material.

[0014] In another aspect of the present disclosure, the plurality of domains have an average size of greater than or equal to about 100 nm to less than or equal to about 5,000 nm.

[0015] According to several aspects, an anti-icing coating decal is disclosed. The decal includes: a polymer film having an outer surface and an inner surface opposite the outer surface, a pressure sensitive adhesive applied to the inner surface, and an anti-icing coating applied to the outer surface. The anti-icing coating includes a continuous phase having a fluoropolymer having a functionality greater than 2, a plurality of domains having a fluorine-free material, and a cross-linking molecule having 4 or more functional groups, the cross-linking molecule combining a portion of the fluoropolymer with a portion of the fluorine-free material through at least one of a diisocyanate-containing portion and a triisocyanate-containing portion. The plurality of domains are dispersed within the continuous phase and are immiscible with the fluoropolymer.

[0016] In another aspect of the present disclosure, the cross-linking molecules comprise nitrogen-containing moieties, oxygen-containing moieties, and combinations thereof.

[0017] In another aspect of the present disclosure, the cross-linking molecule is pentaerythritol propoxylate.

[0018] In another aspect of the present disclosure, the anti-icing coating further comprises 0.5-5 wt % of colloidal silica.

[0019] In another aspect of the present disclosure, the anti-icing coating further comprises at least one of an antioxidant and a hindered amine stabilizer.

[0020] According to several aspects, an anti-icing coating for a vehicle component is disclosed. The anti-icing coating includes a continuous phase having a fluorine-containing polymer formed from a fluorine-containing precursor having a functionality greater than 2 and a plurality of domains having a fluorine-free material. The plurality of domains are dispersed within the continuous phase and can be immersed in the continuous phase. At least a portion of the fluorine-free material is bonded to the fluorine-containing polymer through an isocyanate-containing moiety. The fluorine-containing polymer is cross-linked with a cross-linking molecule having at least four functional groups, the functional groups including nitrogen-containing moieties, oxygen-containing moieties, and combinations thereof.

[0021] In another aspect of the present disclosure, the fluorine-containing precursor includes a fluorinated material having at least one of a hydroxyl group and an amine group. The fluorinated material includes at least one of a fluorinated polyol, a perfluorocarbon, a perfluoropolyether, a polyfluoroacrylate, a polyfluorosilicone, polyvinylidene fluoride, polytrifluoroethylene, and polytetrafluoroethylene.

[0022] In another aspect of the present disclosure, the fluorine-free material includes at least one of poly(acrylic acid), poly(ethylene glycol), poly(2-hydroxyethyl methacrylate), poly(vinylimidazole), poly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline), poly(vinylpyrrolidone), and a modified cellulose polymer, wherein the modified cellulose polymer includes at least one of carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and methyl cellulose.

[0023] In another aspect of the present disclosure, the fluorine-free material is poly(ethylene glycol).

[0024] In another aspect of the present disclosure, an anti-icing coating is applied to an exterior surface of a vehicle component.

[0025] Further areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

[0027] Figure 1 is a functional diagram of a vehicle equipped with a detection system according to an exemplary embodiment;

[0028] Figure 2 is a schematic diagram showing a surface of an article coated with a dual-phase anti-icing coating of the present disclosure according to an exemplary embodiment;

[0029] Figures 3A-3C is a laser scanning confocal microscope image of a dual-phase anti-icing coating according to an exemplary embodiment; and

[0030] Figure 4 is an illustration of a decal with dual phase ice protection according to an exemplary embodiment. DETAILED DESCRIPTION

[0031] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or use. The illustrated embodiments are disclosed with reference to the accompanying drawings, wherein like reference numerals represent corresponding parts in the several drawings. The drawings are not necessarily drawn to scale, and some features may be exaggerated or reduced to show details of particular features. The specific structural and functional details disclosed are not intended to be interpreted as limiting, but rather as a representative basis for teaching those skilled in the art how to practice the disclosed concepts.

[0032] As used herein, a module or control module refers to any one or various combinations of one or more processors, associated memory, and other components operable to execute software, firmware, programs, instructions, routines, codes, and algorithms to provide the described functions. Processors include, but are not limited to, application specific integrated circuits (ASICs), electronic circuits, central processing units, microprocessors, and microcontrollers. Associated memory includes, but is not limited to, read-only memory (ROM), random access memory (RAM), and electrically programmable read-only memory (EPROM). The functions of the control modules set forth in this disclosure can be performed in a distributed control architecture between several networked control modules. A control module may include a variety of communication interfaces, including point-to-point lines or discrete lines and wired or wireless interfaces to other control modules.

[0033] Figure 1 A functional diagram of a non-limiting exemplary vehicle 100 equipped with a detection system 102 is shown. The vehicle 100 generally includes a body 104 having front wheels 106A, 106B and rear wheels 108A, 108B. The front wheels 106A, 106B and rear wheels 108A, 108B are each rotatably positioned near a respective corner of the body 104. The detection system 102 includes a detection module 110 in communication with a plurality of external sensors 112A-112E, including but not limited to optical laser devices, such as a light detection and ranging (LIDAR) device 112A for having a 360 degree view with respect to the vehicle 100, a front view camera 112B, a rear view camera 112C, a side view camera 112D, and a range sensor 112E (such as a sonar device).

[0034] One or more of the external sensors 112A-112E may be equipped with local processing components to process the collected data. The processed data or raw sensor data may be directly transmitted to the detection module 110 for further processing. The processed data may be transmitted to the advanced driver assistance system (ADAS) module 114 to enhance operator awareness, for example, to activate a driver warning interface or to enhance vehicle operation according to the SAE J3016 driving automation levels.

[0035] In order to optimally detect the vehicle's external environment, the sensing surfaces of the sensors 112A-112E should be as free of debris as possible. In wet and frozen operating environments, liquid water may penetrate the mounting surfaces of the sensors 112A-112E and the vehicle body 104 and wet the outer surfaces of the sensors 112A-112E. When liquid water freezes on the sensor surfaces, the formation of ice may adversely affect the operating parameters of the sensors. Similarly, water and sleet may penetrate removable panels of the vehicle 100, such as the gas / charging port 114, and freeze, rendering those removable panels temporarily inoperable.

[0036] The present disclosure provides a dual-phase anti-icing coating having improved durability, improved adhesion to the surfaces of external sensors and panels, and improved tolerance to solvents (such as oils and fuels) compared to known anti-debris coatings. The dual-phase anti-icing coating of the present invention, also referred to as an anti-icing coating, comprises two chemically different materials, including a fluorinated material and a non-fluorinated (fluorine-free) antifreeze material. The dual-phase anti-icing coating can inhibit water wetting and freezing on the surfaces of vehicle sensors and body parts to ensure the normal operation of these sensors and body parts. Unless otherwise specified, as used herein, the terms "composition", "chemical substance" and "material" are used interchangeably and broadly refer to substances containing at least a preferred chemical component, element or compound, but may also contain additional elements, compounds, or substances, including trace impurities.

[0037] Controlled phase separation of two chemically different materials enables the two chemically different materials to come into contact with ice and inhibit wetting of water and formation of ice on the coated surface. The combination of immiscible chemical functionality and controlled phase separation of the anti-icing coating is achieved by using fluorinated material precursors, such as branched fluorinated polyols, which are capable of producing a highly crosslinked network due to the large number of hydroxyl groups found throughout the backbone of the fluorinated polymer and crosslinking molecules with four (4) or more functional groups.

[0038] Prior art teaches that increasing crosslinking will reduce the icephobic properties of the coating (Kevin Golovin et al., Designing durable icephobic surfaces. Sci. Adv. 2, e1501496 (2016). DOI: 10.1126 / sciadv.1501496). In contrast, the anti-icing coating of the present invention has a highly crosslinked network by extending crosslinks along the fluorinated polyol. The highly crosslinked network of the anti-icing coating of the present invention does not produce crystalline regions, thereby forming a hard coating that cannot eliminate ice. Branched fluorinated polyols and crosslinked molecules having four (4) or more functional groups work synergistically to resist water and prevent ice penetration while resisting common solvents (such as oil and fuel) on the road. The fluorinated polymer phase can repel water, while the non-fluorinated solid antifreeze material can prevent ice formation.

[0039] Figure 2 A portion of a coated article 200 is shown having a dual-phase anti-icing coating 202 having a continuous phase 204 and a discrete phase 206. The dual-phase anti-icing coating 202 is disposed on a surface 208 of an article 210 and thus provides anti-icing and anti-wetting properties to the article 210. The discrete phase 206 defines a plurality of domains 212 having an average size of greater than or equal to about 100 nm to less than or equal to about 5,000 nm. It should be understood that Figure 2 The simplified illustration is merely schematic and not to scale because the plurality of domains 212 can be smaller than the domains shown and can be distributed not only at the surface, but also throughout a majority of / throughout the continuous phase 204. In certain aspects, the plurality of domains 212 are substantially evenly or uniformly distributed within the continuous phase 204.

[0040] One of the continuous phase 204 and the discrete phase 206 includes a fluorinated material, also referred to as a primary chemical. The other of the continuous phase 204 and the discrete phase 206 includes an immiscible non-fluorinated material, also referred to as an immiscible secondary chemical. A miscible material, such as a miscible polymer material, is a material that is capable of mixing with another dissimilar material on a molecular scale, whereas a substantially immiscible material cannot be mixed with or distributed into another dissimilar material, but rather forms a distinct phase, layer, intrusion, such as a domain from the primary material without additional manipulation or reaction within the matrix.

[0041] Fluorinated materials are fluoropolymer materials, also known as fluorinated polymers, formed from fluorine-containing precursors having a functionality greater than 2. Fluorine-containing precursors, also known as fluorinated oligomers, are substantially immiscible with non-fluorine-containing materials. In highly crosslinked versions, the fluorinated polymer is typically the continuous phase. A functionality greater than 2 means that each individual precursor molecule has an average of greater than 2 functional groups, such as hydroxyl groups or other functional groups that react to form a crosslinked fluoropolymer network.

[0042] At least a portion of the fluorine-free material is bonded to an isocyanate-containing moiety. An "isocyanate" is a functional group having the formula -N=C=O. For purposes of this disclosure, SC(=O)-N(H)-R is considered to be a derivative of isocyanate.

[0043] exist Figure 2 In the non-limiting embodiment shown, the fluorinated polymer defines a continuous phase. The fluorinated polymer inhibits wetting and penetration of water, while the immiscible fluorine-free material defines a discrete phase and acts as a solid antifreeze for ice. The fluorinated polymer and the fluorine-free material are combined together by multifunctional isocyanates, and the fluorinated polymer is cross-linked with molecules having 4 or more functional groups. The cross-linked molecules with at least 4 functional groups include nitrogen-containing moieties, oxygen-containing moieties, and combinations thereof. It should be understood that the fluorinated polymer can be one of the discrete phase and the continuous phase in the two-phase polymer, and the immiscible fluorine-free material can be the other of the discrete phase and the continuous phase.

[0044] The size of the continuous phase and the discrete phase on the surface is nanometers (nm). The size of ice is a droplet / piece of millimeters (mm) or larger. The continuous phase and the discrete phase of the coating are significantly smaller than ice, so both the fluorinated polymer and the fluorine-free material act on ice. The fluorinated polymer can prevent water wetting and can also reduce the adhesion of ice on the surface. The fluorine-free material is a fluorine-free hygroscopic material and / or a hydrophilic material. A hygroscopic material is a material that can absorb or absorb water in the surrounding environment. A hydrophilic material is a material that has an affinity for water. In a non-limiting exemplary embodiment, the fluorine-free material is poly (ethylene glycol), also known as PEG, which acts as a solid antifreeze. PEG mixes with water molecules on the contact surface and prevents it from crystallizing into ice. By inhibiting the formation of ice, a liquid water layer is maintained on the surface, and the liquid water layer greatly reduces the adhesion of ice.

[0045] Fluorinated polymers are low surface energy materials that inhibit wetting and adhesion, while non-fluorinated hygroscopic or hydrophilic materials can disrupt the contact line of ice along the surface. Low surface energy materials are understood to have a surface tension or surface energy less than or equal to about 50 mJ / m 2 .

[0046] (I) Low surface energy fluorinated polymers (primary chemical substances) are fluorinated polymers with a functionality greater than two (2), such as fluorinated polyols, perfluorocarbons, perfluoropolyethers, polyfluoroacrylates, polyfluorosilicones, polyvinylidene fluoride, polytrifluoroethylene, polytetrafluoroethylene, and copolymers of these materials. These fluorinated polymers have hydroxyl or amine functional groups. Polytetrafluoroethylene with pendant hydroxyl groups is an exemplary embodiment.

[0047] (II) Fluorine-free material (which is a secondary chemical substance) which is immiscible with the fluorine-containing polymer and which is a material such as poly(acrylic acid), poly(ethylene glycol), poly(2-hydroxyethyl methacrylate), poly(vinylimidazole), poly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline), poly(vinylpyrrolidone) and modified cellulose polymers including: carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and methyl cellulose. The secondary chemical substance has a hydroxyl or amine functional group. Poly(ethylene glycol) is an exemplary embodiment.

[0048] (III) adding an isocyanate to covalently bond the primary chemical substance and the secondary chemical substance. The reactant is selected from the group consisting of polyisocyanates, hexamethylene diisocyanate-based monomers, isophorone diisocyanate-based monomers, methylene diphenyl diisocyanate-based monomers, toluene diisocyanate-based monomers, blocked isocyanate monomers, and combinations thereof.

[0049] (IV) Adding crosslinking groups with a functionality of 4 or more to hydroxyl or amine reactive groups. This can include crosslinking agents based on pentaerythritol, triglycerol, di(trimethylolpropane), or combinations thereof. Pentaerythritol propoxylate is an exemplary embodiment.

[0050] (V) Optionally, an ionic substance or an ionic polyol is added. At least one ionic substance is selected from the group consisting of (2,2-bis-(1-(1-methylimidazolium)-methylpropane-1,3-diol bromide), 1,2-bis(2'-hydroxyethylimidazolium) bromide, (3-hydroxy-2-(hydroxymethyl)-2-methylpropyl)-3-methyl-1H-3λ4-imidazol-1-ium bromide, 2,2-bis(hydroxymethyl)butyric acid, N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid, N-methyl-2,2'-iminodiethanol, 3-dimethylamino 1,2-propanediol, 2,2-bis(hydroxymethyl)propionic acid, 1,4-bis(2-hydroxyethyl)piperazine, 2,6-diaminocaproic acid, N,N-bis(2-hydroxyethyl)glycine, 2-hydroxypropionic acid hemi-calcium salt, dihydroxymethylpropionic acid, N-methyldiethanolamine, N-ethyldiethanolamine, N-propyldiethanolamine, N-benzyldiethanolamine, Nt-butyldiethanolamine, bis(2-hydroxyethyl)benzylamine, bis(2-hydroxypropyl)aniline. 2,2-bis(hydroxymethyl)propionic acid (DMPA) is an exemplary embodiment.

[0051] The at least one ionic species is polymerized simultaneously from the isocyanate-containing moiety, the fluorinated polymer, and the non-fluorinated hygroscopic or hydrophilic material, so that the at least one ionic species is located between the fluorinated polymer and the non-fluorinated hygroscopic or hydrophilic material. The at least one ionic species may also be polymerized in the hygroscopic or hydrophilic region. The at least one ionic species does not enter the fluorinated region because it is insoluble in the fluorinated polymer.

[0052] Adding stabilizers directly to polymers helps prevent oxidation, polymer chain breakage, and crosslinking reactions caused by UV exposure or high temperatures. Antioxidants can be added to minimize or terminate oxidation caused by UV or heat. Hindered amine stabilizers are effective against light-induced degradation. Phenyl groups can be added in the chain or at the end of the chain to increase thermal stability. These materials can also be combined with one or more additional materials (such as particulate fillers, pigments, dyes, plasticizers, flame retardants, leveling agents, and adhesion promoters). The particulate filler can be selected from, but not limited to, the group including the following substances: silica, alumina, silicates, talc, aluminosilicates, barium sulfate, mica, diatomaceous earth, calcium carbonate, calcium sulfate, carbon, wollastonite, and combinations thereof; and wherein the particulate filler is optionally surface-modified with a compound selected from the group consisting of fatty acids, silanes, alkyl silanes, fluoroalkyl silanes, organosilicones, alkyl phosphonates, alkyl phosphonic acids, alkyl carboxylates, alkyl disilazanes, and combinations thereof. Additional additives can be incorporated to change the appearance of the coating. 0.5-5 weight percent (wt. %) of colloidal silica may be added to reduce gloss.

[0053] The anti-icing coating can be applied to the intended surface as a solution by drop casting, spraying, roller coating, etc. The solvent is evaporated to form a coating having self-cleaning and easy-cleaning properties. Various exterior surfaces of vehicles can be coated with the dual-phase anti-icing coating of the present disclosure to have increased anti-icing properties and cleanability. The coating can be applied to a variety of surfaces, including surfaces of materials selected from the group consisting of plastics, glass, painted surfaces, metals, and combinations thereof.

[0054] Figures 3A-3C is a laser scanning confocal microscopy image of a dual-phase anti-icing coating with a branched fluorinated polymer in the continuous phase and poly(ethylene glycol) in the discrete phase. Figure 3A Magnifications with a 100 μm scale bar are shown. Figure 3B 25 μm scale bar is shown, Figure 3C A 5 μm scale bar is shown. The biphasic anti-icing coating is impregnated with a fluorescent dye that preferentially enters the polyethylene glycol areas (domains). The film is then imaged using a laser scanning confocal microscope. The sample is excited with an argon laser, which excites the dye and causes it to fluoresce. The more fluorescent areas, the lighter the color, represent areas rich in polyethylene glycol. Figures 3A-3C Discrete regions of secondary chemical phases separated from high fluorine-rich regions were identified.

[0055] Although vehicle applications are often discussed, dual-phase anti-icing coatings can also be used in other applications such as other vehicle applications (e.g., motorcycles and recreational vehicles), aerospace industry (e.g., aircraft, helicopters, drones), marine applications (e.g., ships, personal watercraft, docks), agricultural equipment, industrial equipment, etc., including anti-icing coatings on building gutters and sidewalks.

[0056] The present disclosure provides a method for treating an article. The article may include an external sensor (such as a LIDAR sensor or an ultrasonic sensor), a glass panel, a plastic part, a painted surface, a metal panel, and equivalents and combinations thereof. The method includes (a) obtaining a substrate (such as a sensor, a body part, or a panel); (b) optionally, applying an adhesive layer or a primer to the intended surface of the substrate; (c) forming a polymer solution by combining precursors of a primary chemical and a secondary chemical and diluting the combined precursors with a solvent to a concentration of 5% to 60% by weight of solids including polymer components and fillers. Typical solvents include MEK, MIBK, xylene, butyl acetate, and toluene; (d) spraying the polymer solution onto a predetermined surface of the substrate; and (e) heating to cure the coating or curing at room temperature.

[0057] Possible adhesion promoters include:

[0058] a. Alkoxysilanes that form chemical groups on the surface that bind to polyols or isocyanates, such as (3-glycidyloxypropyl)trimethoxysilane (GPTMS), (3-aminopropyl)triethoxysilane (APS), (3-aminopropyl)triethoxysilane (APS) and (3,3,3-trifluoropropyl)trimethoxysilane (FPTS), or (3-aminopropyl)triethoxysilane (APS) and trimethoxyphenylsilane (TMPS).

[0059] b. Epoxy or polyurethane organic primer.

[0060] c. Adding a third polymer block to a polymer that physically adsorbs to a specific surface. For example, polyurethane forms hydrogen bonds with polyester and nylon surfaces.

[0061] The present disclosure provides another method for treating an article. Figure 4 As shown, the anti-icing coating can be formed into a decal 400. The polymer film 402 includes an inner surface 404 and an outer surface 406 opposite the inner surface 404. The polymer film 402 can include a non-fluorinated polymer or a fluorinated polymer. Fluorinated polymer films include Teflon FEP, Teflon PFA, Teflon AF, NEOFLON TM EFEP or PVDF. Inner surface 404 may be adhesive treated, which means that inner surface 404 is ozone treated, corona treated, chemically etched, or plasma treated. Adhesive layer 408 is applied to treated inner surface 404. Anti-icing coating 410 of the present disclosure is applied to outer surface 406 and cured.

[0062] Adhesive layer 408 can be hot melt adhesive, chemical curing adhesive (epoxy amine) or pressure sensitive adhesive. Pressure sensitive adhesive is defined as referring to a kind of adhesive material of different categories in this article, and described adhesive material has strong and permanent viscosity in dry form (for example, substantially free of solvent and water) at room temperature, and firmly adheres to various surfaces at room temperature, including paper, plastic, glass, wood, cement and metal, without applying pressure exceeding 20 pounds per square inch. These products do not need to be activated by water, solvent or heat, and powerful adhesion can be applied to such materials. They have enough cohesion and elasticity, so although they have strong viscosity, they can be controlled with fingers and removed from smooth surfaces without leaving obvious residue.

[0063] The pressure sensitive adhesive may comprise a linear or branched, random or block polymer having one, two, three or more monomer units. Exemplary pressure sensitive adhesives may include materials selected from adhesives of acrylic resins, polyurethanes, rubbers, styrene-butadiene-styrene copolymers, ethylene vinyl acetate, styrene block copolymers and combinations thereof, such as styrene-ethylene / butylene-styrene (SEBS) block copolymers, styrene-ethylene / propylene (SEP) block copolymers, styrene-isoprene-styrene (SIS) block copolymers, or combinations thereof.

[0064] Comparative Example 1: Example 1 is a dual phase polymer having a branched fluorinated polymer, a poly(ethylene glycol) antifreeze phase, 4,4'-methylene bis(cyclohexylisocyanate) isocyanate, and a tri-reactive group crosslinker (trimethylolpropane).

[0065] Example 1, 4-arm crosslinker: A two-phase polymer containing a branched fluorinated polymer, a poly(ethylene glycol) antifreeze phase, 4,4'-methylene bis(cyclohexyl isocyanate) isocyanate, a four-reactive group crosslinker (pentaerythritol propoxylate). To prepare, a container was charged with Zeffle GK-570 (3.08 g), poly(ethylene glycol) (0.99 g), pentaerythritol propoxylate (0.96 g), and 2-butanone (7.79 g). The solution was mixed until uniform. 4,4'-methylene bis(cyclohexyl isocyanate) (2.77 g) and dibutyltin dilaurate (6.3 μL) were added and mixed until uniform. The resulting solution was used for spraying.

[0066] Example 2, 4-arm crosslinker and addition of charged species: A two-phase polymer containing a branched fluorinated polymer, a poly(ethylene glycol) antifreeze phase, 4,4'-methylene bis(cyclohexyl isocyanate) isocyanate, a four-reactive group crosslinker (pentaerythritol propoxylate), and an ionic species (DMPA). To prepare, a container was charged with Zeffle GK-570 (3.08 g), poly(ethylene glycol) (0.99 g), pentaerythritol propoxylate (0.96 g), DMPA (0.03 g), trimethylamine (0.02 g), and 2-butanone (7.90 g). The solution was mixed until all solids were dissolved. 4,4'-methylene bis(cyclohexyl isocyanate) (2.83 g) and dibutyltin dilaurate (3.7 μL) were added and mixed until uniform. The resulting solution was used for spraying.

[0067] The solvent resistance of the polymers was compared to understand if full cure had occurred and whether the coating would be solvent resistant over its useful life. A solvent resistance test method was used that involved curing the coating, wiping it with a solvent soaked fabric, and inspecting the coating for damage or solvent damage. The coatings were rated on a scale of 0 to 5, with 0 indicating no change and 5 indicating complete debonding. Methyl ethyl ketone (MEK) was used as the solvent because it is the solvent for the liquid formulation of this coating. The ratings are shown in Table 1. Adding a crosslinker with four reactive groups eliminated the solvent damage.

[0068] Table 1. Resistance to solvent damage

[0069] sample Observation score Example 1 1 (mild: almost invisible haze) Example 2 0 (no change) Comparative Example 1 3 (Medium: Obvious haze, stickiness)

[0070] Example 1, Example 2 and Comparative Example 1 are applied to ultrasonic assisted sensors. A combination of painter's tape and sealing film is used to cover the sensor to limit the coating applied to the sensor barrel. A silane solution is prepared from 2% (3-glycidyloxypropyl)trimethoxysilane (GPTMS) in 95% ethanol and 5% water. The silane solution is sprayed onto the sensor at a thickness of approximately 0.5 mils (wet) and allowed to dry. Aerospace primer (PRC-DeSoto CA7502) is sprayed on top according to the manufacturer's instructions. The example coating is sprayed onto the corresponding sensor barrel in 3 separate coats. The mask is removed and the sensor is cured in an oven at 65°C for 4 hours. The resulting coating is approximately 1.5 mils thick after drying.

[0071] The sensor was mounted on a vehicle, the vehicle was placed in a cold room, the temperature was lowered to -10°C, water was sprayed on the sensor, and the sensor operability was checked. The water spraying and the sensor operability were repeated until the sensor failed. The process of spraying water on the sensor and then checking the sensor operability was counted as one cycle. The number of cycles before the sensor failed was calculated as shown in Table 2. An uncoated sensor was used as a control. Multiple numbers indicate that the sensor was retested after thawing. As shown in Table 2, Example 1 and Example 2 best resisted the situation where the sensor was fixed due to water freezing.

[0072] Table 2. Cycle until sensor failure.

[0073] sample Freezing cycles before failure Control – Uncoated Sensor 5,2,7 Example 1 12,11 Example 2 11,11 Comparative Example 1 5,2,11

[0074] The description of the present disclosure is merely exemplary in nature, and variations that do not depart from the general meaning of the present disclosure are intended to fall within the scope of the present disclosure. These variations should not be regarded as departing from the spirit and scope of the present disclosure.

Claims

1. An anti-icing coating, comprising: a continuous phase comprising a first material; a plurality of domains comprising a second material, wherein the plurality of domains are dispersed within the continuous phase and are immersible in the continuous phase; wherein one of the first material and the second material comprises a fluorine-containing polymer formed from a fluorine-containing precursor having a functionality greater than 2; wherein the other of the first material and the second material comprises a fluorine-free material, wherein the fluorine-free material comprises at least one of a hygroscopic material and a hydrophilic material; wherein at least a portion of the fluorine-free material is bonded to the fluorine-containing polymer via an isocyanate-containing moiety; and The fluorine-containing polymer is cross-linked with cross-linking molecules having at least four functional groups, wherein the functional groups include nitrogen-containing moieties, oxygen-containing moieties and combinations thereof.

2. The anti-icing coating according to claim 1, wherein: The first material includes the fluoropolymer; and The second material includes the fluorine-free material.

3. The anti-icing coating according to claim 2, wherein: The fluorine-free material includes at least one of poly(acrylic acid), poly(ethylene glycol), poly(2-hydroxyethyl methacrylate), poly(vinylimidazole), poly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline), poly(vinylpyrrolidone) and a modified cellulose polymer, wherein the modified cellulose polymer includes at least one of carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and methyl cellulose.

4. The anti-icing coating according to claim 2, wherein: The fluorine-free material is poly(ethylene glycol).

5. The anti-icing coating according to claim 2, wherein: The fluorine-containing polymer comprises at least one of fluorinated polyols, perfluorocarbons, perfluoropolyethers, polyfluoroacrylates, polyfluorosiloxanes, polyvinylidene fluoride, polytrifluoroethylene, polytetrafluoroethylene and copolymers thereof.

6. The anti-icing coating of claim 2, wherein the fluorine-containing precursor comprises at least one of a hydroxyl group and an amine functional group.

7. The anti-icing coating of claim 2, wherein the fluorine-containing precursor is polytetrafluoroethylene having a plurality of pendant hydroxyl groups.

8. The anti-icing coating according to claim 2, further comprising at least one ionic substance selected from the group consisting of (2,2-bis-(1-(1-methylimidazolium)-methylpropane-1,3-diol bromide), 1,2-bis(2'-hydroxyethyl)imidazolium bromide, (3-hydroxy-2-(hydroxymethyl)-2-methylpropyl)-3-methyl-1H-3λ4-imidazol-1-bromide, 2,2-bis(hydroxymethyl)butanoic acid, N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid Acid, N-methyl-2,2'-iminodiethanol, 3-dimethylamino-1,2-propanediol, 2,2-bis(hydroxymethyl)propionic acid, 1,4-bis(2-hydroxyethyl)piperazine, 2,6-diaminohexanoic acid, N,N-bis(2-hydroxyethyl)glycine, 2-hydroxypropionic acid hemi-calcium salt, dihydroxymethylpropionic acid, N-methyldiethanolamine, N-ethyldiethanolamine, N-propyldiethanolamine, N-benzyldiethanolamine, N-tert-butyldiethanolamine, bis(2-hydroxyethyl)benzylamine and bis(2-hydroxypropyl)aniline.

9. The anti-icing coating of claim 2, further comprising at least one ionic species polymerized simultaneously from the isocyanate-containing portion, the fluoropolymer, and the fluorine-free material, such that the at least one ionic species is located between the fluoropolymers.

10. The anti-icing coating of claim 1, wherein the plurality of domains have an average size of greater than or equal to about 100 nm to less than or equal to about 5000 nm.

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