WO2016081690A1 - Graphene nanoribbon layers for de-icing and anti-icing applications - Google Patents

Abstract

The present disclosure pertains to methods of preventing or reducing ice formation on a surface by applying a graphene nanoribbon-containing composition to the surface to form a layer associated with the surface. The formed layer can have water contact angles of > 150 degrees, electrical conductivities of > 100 S/m, and resistances of < 500 Ω/sq. The graphene nanoribbons associated with the layer can include a network of graphene nanoribbons that define an electrical pathway. The graphene nanoribbons may constitute < 5 wt% of the layer. The layer can prevent ice formation by repulsion of water from the layer. The layer can reduce ice formation by melting ice from the surface through application of a voltage to the layer (either from an external voltage source or a magnetic field from an electrically conductive structure). The present disclosure also pertains to surfaces that include the aforementioned layers.

Description

TITLE

GRAPHENE NANORIBBON LAYERS FOR DE-ICING AND ANTI-ICING

APPLICATIONS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 62/081,743, filed on November 19, 2014. The entirety of the aforementioned application is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] This invention was made with government support under Grant No. FA9550-14-1-0111, awarded by the U.S. Department of Defense. The government has certain rights in the invention.

BACKGROUND

[0003] Ice formation on surfaces can adversely affect the functioning of various equipment and structures. Current methods of preventing or removing such ice formations have numerous limitations. The present disclosure addresses such limitations.

SUMMARY

[0004] In some embodiments, the present disclosure pertains to methods of preventing or reducing ice formation on a surface. In some embodiments, the methods of the present disclosure include a step of applying a graphene nanoribbon-containing composition to the surface, where the composition forms a layer associated with the surface.

[0005] In some embodiments, the formed layer is hydrophobic. In some embodiments, the formed layer is super hydrophobic, where the contact angle between the layer and water is more than about 150 degrees. In some embodiments, the formed layer has a conductivity of more than about 100 S/m, and a resistance of less than about 500 Ω/sq. [0006] In some embodiments, the formed layer also includes a polymer matrix, where the graphene nanoribbons are dispersed within the polymer matrix. In some embodiments, the graphene nanoribbons associated with the layer include a network of graphene nanoribbons that define an electrical pathway within the layer.

[0007] In some embodiments, the graphene nanoribbons constitute from about 0.1 wt to about 10 wt of the layer. In some embodiments, the graphene nanoribbons constitute less than about 5 wt of the layer.

[0008] In some embodiments, the layer is formed on the surface. In some embodiments, the layer is formed within the surface. In some embodiments, the layer has a thickness ranging from about 1 nm to about 100 μιη. In some embodiments, the layer has a thickness of more than about 100 μπι.

[0009] In some embodiments, the layer prevents and reduces ice formation on the surface. In some embodiments, the layer prevents ice formation by repulsion of water from the layer (also referred to as anti-icing). In some embodiments, the layer reduces ice formation by melting the ice from the surface (also referred to as de-icing). In some embodiments, the melting includes applying a voltage to the layer to result in the heating of the surface. In some embodiments, the voltage is applied from an external voltage source that is separate and apart from the surface (also referred to as active heating). In some embodiments, the voltage is applied through an electrically conductive structure near the surface (e.g., a wire associated with the surface), where the applied voltage produces a magnetic field, and where the magnetic field induces a current in the layer that causes the layer to heat (also referred to as passive heating).

[0010] Further embodiments of the present disclosure pertain to surfaces that include the layers of the present disclosure. Additional embodiments of the present disclosure pertain to the layers of the present disclosure. DESCRIPTION OF THE FIGURES

[0011] FIGURE 1 provides a scheme of a method of preventing or reducing ice formation on a surface.

[0012] FIGURE 2 provides data relating to the structural characterization of graphene nanoribbon (GNR) stacks. FIG. 2A is a schematic of a GNR stack. FIGS. 2B-C provide transmission electron microscopy (TEM, FIG. 2B) and scanning electron microsopy (SEM, FIG. 2C) images of GNR stacks. FIGS. 2D-E show an x-ray diffraction (XRD) pattern (FIG. 2D) and a Raman spectrum (FIG. 2E) of GNR stacks. FIG. 2F shows a thermogravimetric analysis (TGA) curve of GNR stacks under air atmosphere at a rate of 10 °C/minute.

[0013] FIGURE 3 shows data relating to the electrical conductivity of GNR-epoxy composites. FIG. 3A shows a bar-shaped GNR-epoxy composite. FIG. 3B shows an SEM image of a cross- section of a GNR-epoxy composite. FIG. 3C shows a surface resistance of the GNR-epoxy composite. FIG. 3D shows electrical conductivity as a function of GNR weight fraction. The inset shows the electrical conductivity as a function of GNR volume fraction.

[0014] FIGURE 4 shows data relating to the Joule heating of GNR-epoxy composites (this is an example of active heating). FIG. 4A is a schematic of a Joule-heated GNR-epoxy composite device. FIG. 4B is a photograph of a Joule-heated GNR-epoxy composite device. The resistances across each portion are shown. The scale is in cm. FIGS. 4C-E provide heating profiles of the GNR-epoxy composite at different applied voltages. The top surface temperature was measured using an infrared thermometer with a spot size of ~ 2 cm. The three sets correspond to the respective resistance regions shown in FIG. 4B. The tests were conducted at room temperature. The experiment was conducted in a well- ventilated laboratory hood.

[0015] FIGURE 5 summarizes TGA studies of thermal stability of GNR-epoxy composites in air at a heating rate of 10 °C/min. [0016] FIGURE 6 provides data relating to the Joule heating and deicing of helicopter rotor blade segments. FIGS. 6A-B provide schematics of the GNR-epoxy composite adhesive fabrication on a helicopter rotor blade. FIGS. 6C-G provide a schematic of the coating of a rotor blade segment with the GNR-epoxy composite, followed by complete assembly. FIGS. 6H-I provide photographic images of deicing through Joule heating of a 20.3 cm-long segment of the rotor blade. FIG. 6H shows the set-up before ice formation. FIG. 61 shows the set-up after ice formation and before applying a voltage. FIG. 6J shows the set-up after ice removal.

[0017] FIGURE 7 provides images of various conductors and substrates, including an uncoated steel reinforced aluminum conductor (FIG. 7A), a steel reinforced aluminum conductor coated with a GNR layer (FIG. 7B), a helical substrate where a GNR layer could be coated (FIG. 7C), a power cable (FIG. 7D), a cross section of the power cable (FIG. 7E), and the internal current distribution of the power cable (FIG. 7F).

[0018] FIGURE 8 shows the magnetic field strengths of typical transmission lines in two plots (FIG. 8A and FIG. 8B).

[0019] FIGURE 9 shows data relating to the characterization of GNR layers on transmission lines. FIG. 9A shows that GNR layers provide sufficient heat power to melt ice under various weather conditions. FIG. 9B shows that the heat loss of graphene nanoribbon layers was less than 0.01 of the power.

[0020] FIGURE 10 shows the structures of films that contain hexadecyl-functionalized GNRs (HD-GNRs), including an HD-GNR film on a polyimide (PI) substrate (PJ7HD-GNR films, FIG. 10A), and HD-GNR films on a PI substrate coated with a polyurethane (PU) adhesive layer (FIG. 10B).

[0021] FIGURE 11 shows data relating to the contact angle dependence on sheet resistance of PI7HD-GNR films. The concentration of HD-GNRs in ortho dichlorobenzene (ODCB) was 0.5 mg/mL. [0022] FIGURE 12 shows data relating to contact angle dependence on sheet resistance of poly(N-vinylformamide) functionalized graphene nanoribbon films (PI/PVF-GNR films).

[0023] FIGURE 13 shows the structure of a PI/HD-GNR film, where HD-GNRs are embedded within a PU adhesive layer.

[0024] FIGURE 14 shows data relating to contact angle dependence on sheet resistance of PI/HD-GNR films that contain a PU (0.2 vol%) adhesive layer.

[0025] FIGURE 15 shows the structure of a liquid rubber (LR) supported HD-GNR film on a PI surface (PI/LR/HD-GNR film).

[0026] FIGURE 16 shows the contact angle dependence on sheet resistance of HD-GNRs and polystyrene (1%) mixture films.

[0027] FIGURE 17 shows the fabrication of perfluorododecylated graphene nanoribbon (FDO- GNR) films with double- sided tape as an adhesive layer.

[0028] FIGURE 18 shows the correlation between sheet resistance and static water contact angle for various GNR films, including FDO-GNR films.

[0029] FIGURE 19 shows data and images relating to the anti-icing and resistive heating effects of FDO-GNR films.

[0030] FIGURE 20 shows images of de-icing tests performed on FDO-GNR films.

[0031] FIGURE 21 shows an SEM image (FIG. 21A) and a Raman spectrum (FIG. 21B) of FDO-GNRs.

[0032] FIGURE 22 shows X-ray photoelectron spectroscopy (XPS) data of a FDO-GNR film.

[0033] FIGURE 23 shows a de-icing test of the FDO-GNR film supported by double-sided tapes, in which lubricating liquid was added after ice formation. [0034] FIGURE 24 provides images and illustrations of various radomes, including radomes covered with GNR-coated bubble wraps.

[0035] FIGURE 25 provides schemes, images and illustrations of methods of making ethylene tetrafluoroethylene (ETFE)-based bubble wraps (FIGS. 25A-C), coating the PTFE-based bubble wraps with GNR films (FIGS. 25D), and applying the formed structures to various surfaces (FIGS. 25E-H).

[0036] FIGURE 26 provides various data and illustrations relating to the characterization of the GNR-coated PTFE-based bubble wraps, including contact angle illustrations (FIG. 26A), advancing and receding contact angles (FIG. 26B), sliding angle vs. contact angle (FIG. 26C), contact angle hysteresis vs. adhesive strength (FIG. 26D), and ice fractured structures on bubbled surfaces (FIG. 26E).

DETAILED DESCRIPTION

[0037] It is to be understood that both the foregoing general description and the following detailed description are illustrative and explanatory, and are not restrictive of the subject matter, as claimed. In this application, the use of the singular includes the plural, the word "a" or "an" means "at least one", and the use of "or" means "and/or", unless specifically stated otherwise. Furthermore, the use of the term "including", as well as other forms, such as "includes" and "included", is not limiting. Also, terms such as "element" or "component" encompass both elements or components comprising one unit and elements or components that include more than one unit unless specifically stated otherwise.

[0038] The section headings used herein are for organizational purposes and are not to be construed as limiting the subject matter described. All documents, or portions of documents, cited in this application, including, but not limited to, patents, patent applications, articles, books, and treatises, are hereby expressly incorporated herein by reference in their entirety for any purpose. In the event that one or more of the incorporated literature and similar materials defines a term in a manner that contradicts the definition of that term in this application, this application controls.

[0039] Water accumulation and ice formation on various surfaces (e.g., helicopter rotor blades, aircraft wings and tails, wind turbines, windshields, transmission lines, and radiofrequency equipment) is a prevalent problem that degrades performance of the surfaces upon ice accumulation. For instance, helicopter rotor blades are precisely designed and machined to generate airflow that supports buoyancy. However, the presence or accumulation of ice (e.g., snow) on the blade can cause surface roughness or shape modification that can compromise aerodynamic performance by perturbing airflow around the blade. Moreover, ice accumulation on various surfaces (e.g., power line wires and surfaces of power cables) results in the loss of electricity during ice storms. [0040] Methods of ice removal have included spraying of chemicals (e.g., hot fluid), mechanical force, infrared radiation, and Joule heating. However, such methods have numerous limitations.

[0041] The utilization of mechanical forces to remove ice include the use of hammers, mallets, crow bars, baseball bats, and mechanical ice-shedding devices to loosen ice from surfaces through impact. Shovels have also been utilized to throw ice from surfaces. Such widely used approaches for ice removal are very labor intensive and expensive. Moreover, such approaches can damage underlying structures.

[0042] Another mechanical method of removing ice from surfaces is based on rubber or other elastomeric bubble wraps placed on surfaces for protection from ice. After a certain amount of ice accumulation, the ice breaks upon rapid inflation and is carried away by the relative wind or fall by gravity. Such pneumatic bubble wrap systems have low power consumption and operation cost. Such pneumatic bubble wrap systems can also be completely autonomous. However, the main challenge of utilizing pneumatic bubble wrap systems is that residual ice is not fully removed when the bubble wrap inflates. Pneumatic bubble wrap systems also tend to form ice bridges.

[0043] Chemical methods of removing ice from surfaces also suffer from numerous limitations. For instance, various chemical methods are based on wet or dry chemicals applied to reduce the freezing point temperature, break and melt ice, or reduce ice adhesion strength. However, such chemicals could reach water bodies in concentrations that are toxic to the ecosystem. The environment control of chemical pollution and surface corrosion are also significant impediments to the use of chemicals for removing ice formations.

[0044] Another chemical method is based on icephobic coatings applied to the ice-accreting surface to reduce the adhesion strength of ice, thereby preventing or reducing icing. However, icephobic coatings do not completely prevent icing.

[0045] In recent publications, a number of materials (including carbon-based materials, silica- based materials, metal oxide nanostructures, slippery liquid-infused porous surfaces (SLIPS), and textured metallic surfaces) have been reported to show optimal anti-icing performance. However, materials with dual anti-icing and de-icing capabilities have not been reported.

[0046] Several types of carbon-materials (e.g., graphene/Nafion nanohybrids and graphene oxide nanospheres) have also been developed to fabricate super hydrophobic surfaces. However, such materials have not demonstrated any de-icing or anti-icing properties.

[0047] As such, a need exists for improved methods and systems for preventing or removing ice formations on various surfaces. The present disclosure addresses this need.

[0048] In some embodiments, the present disclosure pertains to methods of preventing or reducing ice formation on a surface. In some embodiments illustrated in FIG. 1, the methods include applying a graphene nanoribbon-containing composition to the surface (step 10), where the composition forms a layer associated with the surface (step 12). Thereafter, the formed layer prevents or reduces ice formation on the surface (step 14) by various methods, such as repulsion of water from the surface (step 16), or melting of ice from the surface (step 18). In some embodiments, ice is melted from a surface by active heating steps (step 20), such as the direct application of a voltage to the layer from an external voltage source. In some embodiments, ice is melted from a surface by passive heating steps (step 22), such as the application of voltage to the layer from a magnetic field generated by an electrically conductive structure near the surface (e.g., a wire under or above the surface), where the magnetic field induces a current in the layer that causes the layer to heat.

[0049] Additional embodiments of the present disclosure pertain to surfaces that contain the layers of the present disclosure. Further embodiments of the present disclosure pertain to the actual layers.

[0050] As set forth in more detail herein, various methods may be utilized to apply various graphene nanoribbon-containing composition to various surfaces to form various layers associated with the surfaces. Moreover, the formed layers can prevent or reduce various types of ice formations on a surface by various mechanisms. [0051] Graphene Nanoribbon Compositions

[0052] The present disclosure can utilize various types of graphene nanoribb on-containing compositions (also referred to as compositions). In particular, the compositions of the present disclosure can include various types of graphene nanoribbons. For instance, in some embodiments, the graphene nanoribbons include, without limitation, functionalized graphene nanoribbons, pristine graphene nanoribbons, doped graphene nanoribbons, mixtures of graphene nanoribbons and carbon nanotubes, graphene oxide nanoribbons, reduced graphene oxide nanoribbons, and combinations thereof.

[0053] In some embodiments, the compositions of the present disclosure include mixtures of graphene nanoribbons and carbon nanotubes. In some embodiments, the carbon nanotubes include, without limitation, single-walled carbon nanotubes, double-walled carbon nanotubes, triple-walled carbon nanotubes, multi-walled carbon nanotubes, few-walled carbon nanotubes, functionalized carbon nanotubes, doped carbon nanotubes (e.g., nitrogen-doped carbon nanotubes and boron-doped carbon nanotubes), and combinations thereof. In some embodiments, the carbon nanotubes include multi-walled carbon nanotubes, such as functionalized multi- walled carbon nanotubes.

[0054] In some embodiments, the graphene nanoribbons include functionalized graphene nanoribbons that are functionalized with a plurality of functional groups. In some embodiments, the functional groups include, without limitation, halogenated groups, fluorinated groups, hydrophobic groups, and combinations thereof. In some embodiments, the functional groups include fluorinated groups.

[0055] In some embodiments, the graphene nanoribbons are functionalized with alkyl groups. In some embodiments, the alkyl groups include, without limitation, halogenated alkyl groups, fluorinated alkyl groups, hydrophobic alkyl groups, and combinations thereof. In some embodiments, the alky groups include fluorinated alkyl groups. In some embodiments, the fluorinated alkyl groups include, without limitation, perfluorododecyl groups, perfluorooctyl groups, perfluorodecyl groups, and combinations thereof. [0056] In some embodiments, the graphene nanoribbons are functionalized with hydrophobic alkyl groups. In some embodiments, the hydrophobic alkyl groups include, without limitation, saturated alkyl groups, such as hexadecyl groups. In some embodiments, the graphene nanoribbons include hexadecyl-functionalized graphene nanoribbons.

[0057] In some embodiments, the graphene nanoribbons are functionalized with hydrophobic functional groups. In some embodiments, the hydrophobic functional groups include hydrophobic polymers. In some embodiments, the hydrophobic polymers include, without limitation, polvinyls, poly(N-vinylpyrrolidone), polybutadiene, polystyrene, polyisoprene, poly(N-vinylformamide), and combinations thereof. In some embodiments, the graphene nanoribbons include poly(N-vinylformamide) functionalized graphene nanoribbons.

[0058] The graphene nanoribbons of the present disclosure can include various layers. For instance, in some embodiments, the graphene nanoribbons of the present disclosure include a single layer. In some embodiments, the graphene nanoribbons of the present disclosure include a plurality of layers. In some embodiments, the graphene nanoribbons of the present disclosure include from about 2 layers to about 60 layers. In some embodiments, the graphene nanoribbons of the present disclosure include from about 2 layers to about 10 layers.

[0059] The graphene nanoribbons of the present disclosure can have various widths. For instance, in some embodiments, the graphene nanoribbons of the present disclosure include widths ranging from about 75 nm to about 750 nm. In some embodiments, the graphene nanoribbons of the present disclosure include widths of less than about 500 nm. In some embodiments, the graphene nanoribbons of the present disclosure include widths of less than about 350 nm. In some embodiments, the graphene nanoribbons of the present disclosure include widths of less than about 250 nm. In some embodiments, the graphene nanoribbons of the present disclosure include widths of more than about 250 nm. In some embodiments, the graphene nanoribbons of the present disclosure include widths ranging from about 250 nm to about 350 nm. In some embodiments, the graphene nanoribbons of the present disclosure include widths ranging from about 250 nm to about 500 nm. In some embodiments, the graphene nanoribbons of the present disclosure include widths of about 350 nm. In some embodiments, the graphene nanoribbons of the present disclosure include widths of about 250 nm.

[0060] The graphene nanoribbons of the present disclosure can also have various lengths. For instance, in some embodiments, the graphene nanoribbons of the present disclosure include lengths ranging from about 10 μιη to about 100 μιη. In some embodiments, the graphene nanoribbons of the present disclosure include lengths ranging from about 10 μιη to about 50 μιη. In some embodiments, the graphene nanoribbons of the present disclosure include lengths ranging from about 30 μιη to about 50 μιη.

[0061] The graphene nanoribbons of the present disclosure can also have various length-to-width aspect ratios. For instance, in some embodiments, the graphene nanoribbons of the present disclosure include length-to-width aspect ratios that range from about 100 to about 150. In some embodiments, the graphene nanoribbons of the present disclosure include a length-to-width aspect ratio of about 140. In some embodiments, the graphene nanoribbons of the present disclosure include a length-to-width aspect ratio of more than about 140.

[0062] The graphene nanoribbons of the present disclosure may be derived from various carbon sources. For instance, in some embodiments, the graphene nanoribbons of the present disclosure may be derived from carbon nanotubes, such as multi-walled carbon nanotubes. In some embodiments, the graphene nanoribbons of the present disclosure are derived through the longitudinal splitting (or "unzipping") of carbon nanotubes. Various methods may be used to split (or "unzip") carbon nanotubes to form graphene nanoribbons. In some embodiments, carbon nanotubes may be split by exposure to potassium, sodium, lithium, alloys thereof, metals thereof, salts thereof, and combinations thereof. For instance, in some embodiments, the splitting may occur by exposure of the carbon nanotubes to a mixture of sodium and potassium alloys, a mixture of potassium and naphthalene solutions, and combinations thereof. In some embodiments, the graphene nanoribbons of the present disclosure are made by the longitudinal splitting of carbon nanotubes using oxidizing agents (e.g., KMn0₄). In some embodiments, the graphene nanoribbons of the present disclosure are made by the longitudinal opening of carbon nanotubes (e.g., multi-walled carbon nanotubes) through in situ intercalation of Na/K alloys into the carbon nanotubes. In some embodiments, the intercalation may be followed by quenching with a functionalizing agent (e.g., 1-iodohexadecane) to result in the production of functionalized graphene nanoribbons (e.g., hexadecyl-functionalized graphene nanoribbons).

[0063] Additional variations of such embodiments are described in U.S. Provisional Application No. 61/534,553 entitled "One Pot Synthesis of Functionalized Graphene Oxide and Polymer/Graphene Oxide Nanocomposites." Also see PCT/US2012/055414, entitled "Solvent- Based Methods For Production Of Graphene Nanoribbons." Also see Higginbotham et al., "Low-Defect Graphene Oxide Oxides from Multiwalled Carbon Nanotubes," ACS Nano 2010, 4, 2059-2069. Also see Applicants' co-pending U.S. Pat. App. No. 12/544,057 entitled "Methods for Preparation of Graphene Oxides From Carbon Nanotubes and Compositions, Thin Composites and Devices Derived Therefrom." Also see Kosynkin et al., "Highly Conductive Graphene Oxides by Longitudinal Splitting of Carbon Nanotubes Using Potassium Vapor," ACS Nano 2011, 5, 968-974. Also see WO 2010/14786A1.

[0064] Polymers

[0065] In some embodiments, the compositions of the present disclosure can also include a polymer. In some embodiments, the polymer may be linked to graphene nanoribbons as functional groups. In some embodiments, the polymer is mixed with the graphene nanoribbons in the composition to form a polymer matrix.

[0066] The compositions of the present disclosure can include various polymers. For instance, in some embodiments, the polymers include, without limitation, epoxy polymers, polyepoxides, polyimides, polyethereimides, polylactic acids, polyglycolic acids, polylactones, polyamines, polyacrylates, polycyanoacrylates, polystyrenes, polybutadienes, polyurethane, epoxy resins, nylons, polyesters, acrylic resins, hydrogenated nitrile, butadiene rubbers, synthetic rubbers, natural rubbers, and combinations thereof. In some embodiments, the polymers include epoxy polymers. [0067] Ceramic Materials

[0068] In some embodiments, the compositions of the present disclosure can also include a ceramic material. In some embodiments, the ceramic material may be mixed with the graphene nanoribbons in the composition to form a ceramic material matrix.

[0069] In some embodiments, the ceramic materials may include, without limitation, crystalline ceramics, non-crystalline ceramics, metals, metal oxides, metal carbides, transition metals, transition metal oxides, transition metal carbides, metalloids, and combinations thereof. In some embodiments, the ceramic materials may include, without limitation, silicon carbide, tungsten carbide, aluminum oxide, zinc oxide, boron nitride, and combinations thereof. In some embodiments, the compositions of the present disclosure may include mixtures of polymers and ceramic materials.

[0070] Solvents

[0071] The compositions of the present disclosure may also include various solvents. For instance, in some embodiments, the compositions of the present disclosure may be embedded in various organic solvents. In some embodiments, the organic solvents include, without limitation, chloroform, ortho-dichlorobenzene, dimethyl formamide, and combinations thereof.

[0072] Fabrication

[0073] The compositions of the present disclosure may be fabricated by various methods. For instance, in some embodiments, the compositions of the present disclosure are fabricated by mixing graphene nanoribbons with a solvent. In some embodiments, the compositions of the present disclosure are fabricated by mixing graphene nanoribbons with a polymer, a ceramic material, or combinations thereof.

[0074] In some embodiments, the compositions of the present disclosure are fabricated by mixing graphene nanoribbons with monomers to form a mixture. Thereafter, the mixture is cured to form the composition. In some embodiments, the monomers can include, without limitation, epoxides, imides, lactic acids, glycolic acids, lactones, amines, acrylates, cyanoacrylates, styrenes, vinyl monomers, butadienes, isoprene, and combinations thereof. In some embodiments, the monomers include various vinyl monomers, such as N-vinylpyrrolidone, butadiene, styrene, isoprene, and mixtures thereof. In some embodiments, the monomers include an epoxide.

[0075] Moreover, various methods may be utilized to cure the mixture. For instance, in some embodiments, the curing step includes heating the mixture. In some embodiments, the curing step includes adding a hardener to the mixture.

[0076] In some embodiments, the compositions of the present disclosure are fabricated by splitting carbon nanotubes to form graphene nanoribbons. Thereafter, the formed graphene nanoribbons may be mixed with functional groups to form functionalized graphene nanoribbons. Suitable methods by which to carry out the aforementioned steps were described previously.

[0077] The compositions of the present disclosure may be fabricated at various times. For instance, in some embodiments, the compositions of the present disclosure may be fabricated during the application of the composition to a surface. In some embodiments, the compositions of the present disclosure are fabricated before the applying step. In some embodiments, the compositions of the present disclosure are fabricated after the applying step.

[0078] The compositions of the present disclosure can also be in various states. For instance, in some embodiments, the compositions of the present disclosure are in the form of a liquid, a solid, an emulsion, a vapor, and combinations thereof. In some embodiments, the compositions of the present disclosure are in the form of an emulsion, such as a paint. In some embodiments, the compositions of the present disclosure are in the form of a solid, such as a ribbon or a flat structure.

[0079] Application of Compositions to a Surface

[0080] Various methods may be utilized to apply the compositions of the present disclosure to a surface. For instance, in some embodiments, the compositions of the present disclosure are applied to a surface by methods that include, without limitation, chemical vapor deposition, spraying, spray-coating, sputtering, coating, spin coating, blade coating, rod coating, film coating, printing, painting, brushing, mechanical transfer, annealing, and combinations thereof.

[0081] In some embodiments, the compositions of the present disclosure are applied to a surface through an annealing step. In some embodiments, the annealing step adhesively associates the formed graphene layer to the surface.

[0082] The compositions of the present disclosure can be applied to a surface at various temperatures. For instance, in some embodiments, the applying step occurs at temperatures of more than about 100 °C. In some embodiments, the applying step occurs at temperatures of more than about 200 °C. In some embodiments, the compositions of the present disclosure are spray coated onto a surface at 210 °C.

[0083] In some embodiments, the compositions of the present disclosure are applied to the surface by mechanically transferring a pre-formed composition to the surface (e.g. a solid composition). In some embodiments, the compositions of the present disclosure are applied to the surface by helically winding the composition to the surface. In some embodiments, the compositions of the present disclosure can be helically wound around a surface (e.g., a wire, cable or polymer film) to form a ribbon. In some embodiments, the compositions of the present disclosure can form on a helically wound surface that has a ribbon like structure, where the composition is applied on the outer surface of the ribbon.

[0084] The compositions of the present disclosure can be applied to a surface at different times. For instance, in some embodiments, the compositions of the present disclosure are applied to a surface after the manufacture of the surface. In some embodiments, the compositions of the present disclosure are applied to the surface during the manufacture of the surface.

[0085] Layers

[0086] The compositions of the present disclosure can form a layer associated with a surface after the application of the composition to the surface. In some embodiments, the layers of the present disclosure are formed on the surface. In some embodiments, the layers of the present disclosure are formed within the surface. Additional embodiments of the present disclosure pertain to the formed layers.

[0087] The layers of the present disclosure can have various thicknesses. For instance, in some embodiments, the layers of the present disclosure have a thickness ranging from about 1 nm to about 1 cm. In some embodiments, the layers of the present disclosure have a thickness ranging from about 1 nm to about 100 μιη (e.g., embodiments where the layers of the present disclosure form directly on the surface). In some embodiments, the layers of the present disclosure have a thickness of more than about 1 μιη. In some embodiments, the layers of the present disclosure have a thickness ranging from about 1 nm to about 100 μιη. In some embodiments, the layers of the present disclosure have a thickness ranging from about 5 nm to about 500 nm. In some embodiments, the layers of the present disclosure have a thickness ranging from about 10 nm to about 100 nm. In some embodiments, the layers of the present disclosure have a thickness ranging from about 50 nm to about 100 nm. In some embodiments, the layers of the present disclosure have a thickness ranging from about 20 nm to about 30 nm. In some embodiments, the layers of the present disclosure have a thickness of about 30 nm.

[0088] In some embodiments, the layers of the present disclosure have a thickness of more than about 100 μιη (e.g., embodiments where the layers of the present disclosure are embedded within a surface) For instance, in some embodiments, the layers of the present disclosure have thicknesses that range from about 100 μιη to about 1 cm. In some embodiments, the layers of the present disclosure have thicknesses that range from about 500 μιη to about 100 mm. Additional thicknesses can also be envisioned.

[0089] The graphene nanoribbons in the layers of the present disclosure can have various arrangements. For instance, in some embodiments, the graphene nanoribbons associated with the layer are in contiguous sheets. In some embodiments, the graphene nanoribbons associated with the layer are in disordered form. In some embodiments, the graphene nanoribbons associated with the layer are substantially aligned. [0090] In some embodiments, the graphene nanoribbons form a network within the layer. For instance, in some embodiments, the graphene nanoribbons form an interconnected web within the layer. In some embodiments, the graphene nanoribbons associated with the layer include bundles of graphene nanoribbons. In some embodiments, the graphene nanoribbons associated with the layer include a network of graphene nanoribbon bundles. In some embodiments, the graphene nanoribbon network defines an electrical pathway within the layer.

[0091] The layers of the present disclosure can have various amounts of graphene nanoribbons. For instance, in some embodiments, the graphene nanoribbons constitute from about 0.1 wt to about 10 wt of the layer. In some embodiments, the graphene nanoribbons constitute from about 0.2 wt to about 5 wt of the layer. In some embodiments, the graphene nanoribbons constitute less than about 5 wt of the layer.

[0092] In some embodiments, the layers of the present disclosure also include a polymer matrix, a ceramic matrix, or combinations thereof. In some embodiments, the layers of the present disclosure include a polymer matrix. In some embodiments, the polymer matrix includes cross- linked polymers. In some embodiments, the graphene nanoribbons are dispersed within the polymer matrix. In some embodiments, the graphene nanoribbons are embedded within the polymer matrix. In some embodiments, the graphene nanoribbons are cross-linked with the polymer matrix.

[0093] In some embodiments, the layers of the present disclosure are hydrophobic. In some embodiments, the layers of the present disclosure are super hydrophobic. Super hydrophobic layers generally refer to layers where the contact angle between the layer and water is more than about 150 degrees.

[0094] In some embodiments, the contact angle between the layer and water ranges from about 100 degrees to about 160 degrees. In some embodiments, the contact angle between the layer and water ranges from about 140 degrees to about 160 degrees. In some embodiments, the contact angle between the layer and water ranges from about 140 degrees to about 150 degrees. In some embodiments, the contact angle between the layer and water ranges from about 140 degrees to about 150 degrees. In some embodiments, the contact angle between the layer and water is about 150 degrees. In some embodiments, the contact angle between the layer and water is more than about 150 degrees.

[0095] The layers of the present disclosure can also have various electrical conductivities. For instance, in some embodiments, the layers of the present disclosure have a conductivity ranging from about 10^"5 S/m to about 500 S/m. In some embodiments, the layers of the present disclosure have a conductivity ranging from about 0.5 S/m to about 500 S/m. In some embodiments, the layers of the present disclosure have an electrical conductivity ranging from about 50 S/m to about 100 S/m. In some embodiments, the layers of the present disclosure have a conductivity of more than about 100 S/m.

[0096] The layers of the present disclosure can also have various resistivities. For instance, in some embodiments, the layers of the present disclosure have a resistance ranging from about 1 Ω/sq to about 1000 Ω/ sq. In some embodiments, the layers of the present disclosure have a resistance ranging from about 1 Ω/sq to about 800 Ω/ sq. In some embodiments, the layers of the present disclosure have a resistance ranging from about 200 Ω/sq to about 400 Ω/ sq. In some embodiments, the layers of the present disclosure have a resistance of less than about 750 Ω/sq. In some embodiments, the layers of the present disclosure have a resistance of less than about 500 Ω/sq. In some embodiments, the layers of the present disclosure have a resistance of about 1 Ω/sq.

[0097] The layers of the present disclosure can have various levels of transparency. For instance, in some embodiments, the layers of the present disclosure have optical transparencies of more than about 75%. In some embodiments, the layers of the present disclosure have optical transparencies of more than about 85%. In some embodiments, the layers of the present disclosure have optical transparencies of more than about 90%.

[0098] In some embodiments, the layers of the present disclosure are radio frequency (RF) transparent. As such, in some embodiments, the RF transparent layers of the present disclosure are not expected to interfere with RF waves from various sources (e.g. radar, communication signals, cell phones, GPS devices, and the like). As such, when various surfaces become free of water or ice, the optical transparency of the surfaces can be maintained in accordance with the methods of the present disclosure.

[0099] In some embodiments, the layers of the present disclosure may also be associated with a lubricant. In some embodiments, the lubricant is positioned above the layer. In some embodiments, the lubricant includes a lubricating liquid, such as heptacosafluorotributylamine.

[00100] In some embodiments, the methods of the present disclosure also include a step of applying a lubricant to the layer. In some embodiments, the applying of the lubricant occurs by methods that were described previously.

[00101] The layers of the present disclosure can also have various shapes. For instance, in some embodiments, the layers of the present disclosure are in the form of a coating or a film on the surface. In some embodiments, the layers of the present disclosure cover an entire surface. In some embodiments, the layers of the present disclosure partially cover a surface. In some embodiments, the layers of the present disclosure only cover one side of a surface. In some embodiments, the layers of the present disclosure cover opposite sides of a surface.

[00102] Surfaces

[00103] The layers of the present disclosure can be associated with various surfaces. Additional embodiments of the present disclosure pertain to surfaces that include the layers of the present disclosure. In some embodiments, the surface includes, without limitation, wire surfaces, transmission line surfaces, radome surfaces, window surfaces, automobile surfaces, aircraft surfaces, ship surfaces, building surfaces, antenna surfaces, radar surfaces, solar panel surfaces, solar plant surfaces, wind turbine surfaces, radiofrequency equipment surfaces, mat surfaces, blanket surfaces, wrapping surfaces, tape surfaces, glass-based surfaces, quartz-based surfaces, alumina-based surfaces, silicon-based surfaces, plastic-based surfaces, polymer-based surfaces, electrically conductive surfaces, and combinations thereof.

[00104] The surfaces of the present disclosure may have various angles. For instance, in some embodiments, the surfaces of the present disclosure may be flat. In some embodiments, the surfaces of the present disclosure may be tilted. In some embodiments, the surfaces of the present disclosure have an angle of more than about 10 degrees. In some embodiments, the surfaces of the present disclosure have an angle of about 50 degrees.

[00105] In some embodiments, the surfaces of the present disclosure may be inflated. In some embodiments, the surfaces of the present disclosure are in the form of bubble wraps, such as pneumatic bubble wraps, elastomeric bubble wraps, and the like. In some embodiments, the surfaces of the present disclosure include ethylene tetrafluoroethylene (ETFE). In some embodiments, the surfaces of the present disclosure include ETFE-based bubble wraps.

[00106] In some embodiments, the surfaces of the present disclosure are in the form of a wire. In some embodiments, the wire includes, without limitation, power lines, cables, reinforced cables, power cables, conductors, transmission lines, foils, metal foils, dielectric foils, and combinations thereof. In some embodiments, the surfaces of the present disclosure include high voltage cables, aluminum conductors, steel-reinforced aluminum conductors, aluminum strands, and combinations thereof.

[00107] In some embodiments, the surfaces of the present disclosure include polyimide surfaces. In some embodiments, the surfaces of the present disclosure include aircraft surfaces, such as helicopter rotor blades, aircraft wings and tails, aircraft wing leading edges, and the like. In some embodiments, the surfaces of the present disclosure are in the form of polymer films, such as polyimide films. In some embodiments, the surfaces of the present disclosure lack metallic compositions, such as nickel.

[00108] In some embodiments, the surfaces of the present disclosure are on an exterior of a structure. In some embodiments, the surfaces of the present disclosure are within an interior of a structure. In some embodiments, the surfaces of the present disclosure are on an exterior and within an interior of a structure. [00109] In some embodiments, the surfaces of the present disclosure are electrically conductive. In some embodiments, the surfaces of the present disclosure provide electrical current to the layer, which in turn causes the layer to heat.

[00110] In some embodiments, the surface is near an electrically conductive structure. In some embodiments, voltage applied through the electrically conductive structure produces a magnetic field, where the magnetic field induces a current in the layer, and where the induced current causes the layer to heat.

[00111] In some embodiments, the electrically conductive structure near the surface is an internal structure associated with the surface. In some embodiments, the electrically conductive structure is above the surface. In some embodiments, the electrically conductive structure is below the surface. In some embodiments, the electrically conductive structure is within the surface. In some embodiments, the electrically conductive structure and the graphene nanoribbon layer are both within the surface.

[00112] In some embodiments, the electrically conductive structure is a wire associated with the surface (e.g., a wire above, below or within the surface). In some embodiments, the electrically conductive structure has a current greater than about 100 Amps. In some embodiments, the electrically conductive structure has a current between about 100 Amps and about 200 Amps. In some embodiments, the electrically conductive structure (e.g., wire) is coated with an insulating sheath, and the insulating sheath is further coated with a surface containing a graphene nanoribbon layer.

[00113] The surfaces of the present disclosure may be associated with a layer in various manners. In some embodiments, the surfaces of the present disclosure may be indirectly associated with a layer (e.g., embodiments where the layer may be on a surface of another structure that is directly associated with the surface). In some embodiments, the surfaces of the present disclosure may be directly associated with a layer [00114] The surfaces of the present disclosure may be associated with a layer by various types of interactions. For instance, in some embodiments, the surfaces of the present disclosure may be associated with a layer through at least one of covalent bonds, non-covalent bonds, physisorption, hydrogen bonds, van der Waals interactions, London forces, dipole-dipole interactions, and combinations thereof. In some embodiments, the surfaces of the present disclosure are cross-linked to a layer.

[00115] In some embodiments, the surfaces of the present disclosure may be associated with a layer through an adhesive layer. As such, in some embodiments, the surfaces of the present disclosure also include an adhesive layer. In some embodiments, the adhesive layer is positioned between the surface and the layer. In some embodiments, the adhesive layer includes, without limitation, polyurethanes, epoxy resins, polyimides, polyethereimides, rubbers, polyesters, and combinations thereof.

[00116] In some embodiments, the methods of the present disclosure also include a step of applying an adhesive layer to the surface. In some embodiments, the applying of the adhesive layer occurs before, during or after the applying of the composition. In some embodiments, the applying of the adhesive layer occurs by methods that were described previously.

[00117] Prevention or Reduction of Ice Formation

[00118] The methods of the present disclosure can be utilized prevent or reduce the formation of various types of ice in various manners. In some embodiments, the ice includes, without limitation, ice particles, frost, snow, sleet, hail, and combinations thereof. In some embodiments, the ice includes snow.

[00119] In some embodiments, the layers of the present disclosure prevent ice formation on a surface (also referred to as anti-icing). In some embodiments, the layers of the present disclosure reduce ice formation on a surface (also referred to as de-icing). In some embodiments, the layers of the present disclosure prevent and reduce ice formation on a surface. [00120] In some embodiments, the layers of the present disclosure prevent ice formation on a surface by repulsion of water from the layer. For instance, in some embodiments, a hydrophobic layer repels water from the layer before it is converted to ice.

[00121] In some embodiments, the layers of the present disclosure reduce ice formation by melting the ice from the surface. The melting of ice from a surface can occur by various mechanisms. For instance, in some embodiments, heat from a layer of the present disclosure induces the formation of a thin (e.g., up to 1 mm) water layer between the layer and accumulated ice. Thereafter, the remaining ice falls off due to gravity.

[00122] In some embodiments, the melting of the ice includes a step of applying a voltage to the layer. In some embodiments, the application of voltage to the layer results in the heating (i.e., Joule heating or resistive heating) of the surface. This in turn results in the melting of the ice.

[00123] Voltage may be applied to a layer from various sources. In some embodiments, the voltage is applied from an external voltage source that is separate and apart from the surface. For instance, in some embodiments, the voltage is provided by a power supply, portable electrical devices, towable electric generators, a transmission line that is coated with the surface, or any other source of electric power.

[00124] In some embodiments, a conductivity current within a layer is induced by a magnetic field generated from an electrically conductive structure (e.g., a wire). For instance, in some embodiments where the layers of the present disclosure are associated with or near an electrically conductive structure (e.g., electrical wire), the generated magnetic field that surrounds the electrically conductive structure (e.g., wire) carrying electric current can supply induced current in the layer and thereby cause the heating of the layer. As such, in some embodiments, the heating of a surface layer can occur passively without the direct application of voltage to a layer from external sources. In some embodiments, such passive heating can occur year round.

[00125] In some embodiments, the passive heating of a layer by a surface can be very efficient. For instance, in some embodiments, the percentage power loss from the surface due to the passive heating can be less than about 10% of the power in the surface. In some embodiments, the percentage power loss from the surface due to the passive heating can be less than about 1% of the power in the surface. In some embodiments, the percentage power loss from the surface due to the passive heating can be less than about 0.1% of the power in the surface. In some embodiments, the percentage power loss from the surface due to the passive heating can be less than 0.01% of the power in the surface.

[00126] The layers of the present disclosure can prevent or reduce ice formation on a surface at various environmental temperatures. For instance, in some embodiments, the layers of the present disclosure prevent or reduce ice formation at environmental temperatures below 0 °C. In some embodiments, the layers of the present disclosure prevent or reduce ice formation at environmental temperatures below -10 °C. In some embodiments, the layers of the present disclosure prevent or reduce ice formation at environmental temperatures below -20 °C. In some embodiments, the layers of the present disclosure prevent or reduce ice formation at environmental temperatures between about 0 °C and about -25 °C. In some embodiments, the layers of the present disclosure prevent or reduce ice formation at environmental temperatures below -30 °C. In some embodiments, the layers of the present disclosure prevent or reduce ice formation at environmental temperatures below -40 °C. In some embodiments, the layers of the present disclosure prevent or reduce ice formation at environmental temperatures below -60 °C.

[00127] Advantages

[00128] The layers of the present disclosure can be manufactured, maintained, installed and operated in a facile manner with minimal electric power consumption. Moreover, the layers of the present disclosure are compact and lightweight. Furthermore, the layers of the present disclosure require minimal graphene nanoribbon content. As such, the layers of the present disclosure can provide numerous advantages and applications. For instance, in some embodiments, the layers of the present disclosure can be utilized for both de-icing and anti-icing functions in a way that promotes a very efficient use of energy. In some embodiments, the layers of the present disclosure provide anti-icing and de-icing activities, even without electrical resistive heating (e.g., embodiments where electrical wires are the surfaces).

[00129] Additional Embodiments

[00130] Reference will now be made to more specific embodiments of the present disclosure and experimental results that provide support for such embodiments. However, Applicants note that the disclosure herein is for illustrative purposes only and is not intended to limit the scope of the claimed subject matter in any way.

[00131] Example 1. Composites of graphene nanoribbon stacks and epoxy for joule heating and deicing of structures

[00132] In this Example, Applicants demonstrate the fabrication of a conductive composite of graphene nanoribbon (GNR) stacks and epoxy. The epoxy is filled with the GNR stacks, which serve as a conductive additive. The GNR stacks are on average 30 nm thick, 250 nm wide and 30 μιη long. The GNR-filled epoxy composite exhibits a conductivity of >100 S/m at 5 wt GNR content.

[00133] In this Example, Applicants also demonstrate the application of the GNR-epoxy composite for deicing of surfaces through Joule (voltage-induced) heating generated by the voltage across the composite. In particular, a power density of 0.5 W/cm was delivered to remove ~l-cm- thick (14 g) monolith of ice from a static helicopter rotor blade surface at -20 °C

[00134] The helicopter rotor blade system consisted of a rotor blade and a typical protective metal sleeve bonded with epoxy composite. By adding GNR stacks to the interlayer epoxy composite, the composite was made conductive. This in turn generated thermal energy upon applied voltage for deicing of the blade surface.

[00135] The GNR stacks used in this Example are multilayered with ~ 30 nm thickness obtained from unzipping of multiwalled carbon nanotubes. They are a quasi one-dimensional sp -carbon nano structure and an analogue of graphene that has high electrical conductivity. GNR stacks embedded in an epoxy-based polymer matrix could provide tunable electrical conductivity for the otherwise insulating polymer. GNR stacks are desirable conductive additives because of their good electrical and thermal conductivities. Their high aspect ratios permit small amounts to form percolative networks. If long enough, they need only be a relatively small fraction of a polymer composite to provide significant conductivity enhancement to the composite.

[00136] Example 1.1. GNR-epoxy composite fabrication

[00137] Pristine GNR stacks were obtained from AZ Electronic Materials Corp. (now EMD- Merck, H-GNRs, Batch no: 2699-119). The GNRs were used without any further treatments. To prepare a GNR-epoxy composite, 12 to 290 mg of GNRs were added and blended in 3.9 mL epoxy (Loctite) matrix with a spatula. 1.1 mL hardener (Loctite) was added and further blended. GNR-epoxy composites containing GNRs of -0.2 to 5 wt (of total composite mass) were thus produced. Larger samples were prepared by scaling according to the above ratio of GNRs, epoxy and hardener weights. The composites were heated on a hot plate or in an oven at 70 °C for 3 hours for curing.

[00138] Example 1.2. Characterization

[00139] Transmission electron micrographs (TEMs) of samples prepared on an amorphous carbon-coated TEM grid were acquired with a JEOL 21 OOF field emission gun transmission electron microscope (TEM). TEM samples were prepared by placing ~ 1 mg of the sample in o/t/zodichlorobenzene (ODCB) (Sigma- Aldrich). The mixture was then sonicated to form a dispersion. The dispersion was then drop casted onto the grid.

[00140] Scanning electron micrographs (SEMs) of powder samples placed on a double- sided carbon tape were acquired with a JEOL 6500 field emission gun scanning electron microscope. Raman spectral plots of powder samples placed on a glass slide were acquired with a Renishaw in Via Raman microscope equipped with 514 nm Ar ion laser and WiRe software. X-ray diffractograms of powder samples mounted on a grooved zero background holder were acquired with a Rigaku D/Max Ultima II Powder X-ray diffractometer equipped with a Cu Ka radiation source (λ = 1.5418 A) and JADE 2009 software.

[00141] Example 1.2. Electrical measurements of GNR-epoxy composites

[00142] About -0.2 to 5 wt GNR in epoxy samples were prepared as described above. The composites were cast in a silicone mold with a rectangular groove. The surfaces were smoothed with a spatula. The samples were then heated on a hot plate at 70 °C for 3 hours. The molded rectangular bar of cured GNR-epoxy composite (dimensions, Iwh: 2.5 x 0.6 x 0.5 cm ) were used in all conductivity measurements. Colloidal silver paste (Pelco Colloidal Silver Liquid, Ted Pella) was applied on two ends of the sample to reduce contact resistance between the composite and the probes during resistance measurement. The two probes of a Cen-Tech digital multimeter were placed on the silver-coated ends of the composite bar to measure its resistance (J?). Surface resistance (R_s), a dimensionless resistance, was calculated based on the measured resistance and composite geometry with R_S = R χ _w/j _> where w and / are the width and length of the composite bar, respectively. The DC conductivity, was calculated with &_Q = 7 , where h is the height of the composite bar.

[00143] Example 1.3. Joule heating and deicing

[00144] Joule heating experiments were conducted as described herein by applying various constant voltages across the device. DC voltages were used in all cases. The deicing experiment was conducted at—20 °C in a Styrofoam™ box by clamping the rotor blade segment on a ring stand. The box was cooled to—20 °C by placing chunks of dry ice in it. Thereafter, cold water was sprayed on the rotor blade segment from a wash bottle to form ice. The temperature was stabilized at 20 °C by adding or removing dry ice chunks. A constant voltage was applied across electrodes attached on both sides of the rotor blade segment. [00145] In FIGS. 2A-C, the GNR stacks are shown to have up to 60 layers. In addition, the GNR stacks are 30 nm thick, 350 nm wide, and 50 μηι long. The length-to-width aspect ratio is

-140. The (002) diffraction peak at 26.3° reveals a d-spacing of -3.34 A for the GNR stacks (FIG. 2D). The Raman spectrum exhibits characteristic well-defined G and 2D bands at -1587 cm^" and -2688 cm^" , respectively (FIG. 2E). The G band is the stretching mode of the sp carbon atoms, whereas the 2D band is the breathing mode of the sp rings, emerging from the two-phonon double resonance scattering, thus signifying a very high basal plane π-conjugated sp -carbon structure. In the case of the D band, it is produced from a one-phonon double resonance process, where the Raman fundamental selection rule of momentum conservation only becomes satisfied with the presence of defects, unlike the two-phonon double resonance 2D band.

[00146] The pronounced intensity of the D band in the Raman spectrum of the GNR stacks can be attributed to the relatively large amount of edges, whereby the edges allow laser-excited electrons in the material to be backscattered in order to satisfy the Raman fundamental selection rule. The edges of the GNR stacks provide defect sites for the observation of an intense D band since the GNR stack width (up to 350 nm) is smaller than the laser spot diameter (a few microns). In addition, the GNR stacks are stable in air at room temperature, and oxidative decomposition only commences above 400 °C by thermogravimetric analysis (TGA) (FIG. 2F). The material's structural and chemical stability make it suitable for Joule heating and deicing applications.

[00147] The fabricated composites are used in conductivity measurements by applying voltage across the bar from the contacts at the ends (FIG. 3A). The GNR stacks form a network of percolating electrical channels inside the cross-linked epoxy matrix to generate an electrically conducting composite material (FIG. 3B). The dark regions represent the interconnected GNR stacks. The brighter regions signify charge accumulation by the insulating epoxy under the electron beam of the scanning electron microscope (SEM). The composite produces resistance that reaches as low as 1 Ω/α at 5 wt GNR content (FIG. 3C). The GNR-epoxy composite produces conductivity of 10^~4 S/m at 0.1 wt GNR content, and the conductivity is 100 S/m at 5 wt% (2.5 vol%) (FIG. 3D).

[00148] Example 1.4. Joule heating of GNR-Epoxy composites

[00149] The GNR-epoxy composite was divided into segments with silver contacts deposited at the ends of the sample and internal segments for resistance measurement (FIGS. 4A-B). Voltage was applied across the entire sample from the two ends. The temperature of each segment was measured to evaluate the temperature across the composite during Joule heating (FIGS. 4C-E). Each segment of the device has a different resistance value due to a slight variation in average thickness. Since the current through the entire composite is the same, the higher resistance segment is expected to exhibit higher temperature due to higher power (P = l²R).

[00150] The heating profiles of the composite segments are shown in the time-dependent temperature profiles in (FIGS. 4C-E). Each profile shows that the right end has higher temperature than the left end because of higher resistance. Though the left segment has a higher resistance (and thus higher power) than the middle segment, its temperature is comparable to that of the middle segment because of greater heat dissipation. The temperatures increase with applied voltage for all segments (FIGS. 4C-E).

[00151] As the voltage increases, the power delivered through the composite increases according to P =— , generating higher surface temperature. However, since there is higher heat dissipation with increased power, the effect is non-linear. For the first segment at 20 V, the temperature plateaus at 45 °C with an applied voltage of 20 V (FIG. 4C). When the voltage is increased to 40 V, the power increases 4x but the temperature rises 2.5x. Similar behavior is demonstrated in all three segments. This shows that more heat is dissipated at higher power (FIGS. 4C-E). Such segmental tunability of temperature could be advantageous for removing varying amounts of ice on a structure such as a rotor blade with higher ice accretion at the leading edge. [00152] Thermogravimetric analysis (TGA) shows that the onset of decomposition of the GNR- epoxy composite is at -300 °C in air (FIG. 5). The TGA curve for the GNR-epoxy composite coincides with that of neat epoxy composite below 400 °C. After 400 °C, decomposition of the GNR stacks contribute to the GNR-epoxy weight loss. Because the GNR additive is more stable toward oxidative decomposition than the epoxy used here, it gives room for use of more thermally stable epoxy in an oxygen-containing environment.

[00153] Example 1.5. Deicing experiments

[00154] FIG. 6 illustrates a deicing experiment that was conducted in a Styrofoam box held at 20 °C. A GNR-epoxy composite is demonstrated as a deicing heating layer that holds together a rotor blade and its nickel sleeve while delivering heat for deicing of the nickel surface. A segment of a commercial rotor blade and its epoxy overlayer along with its standard nickel abrasion shield were used in this experiment (Carson Helicopter). Since nickel is thermally conductive, heat can be transferred from the GNR-epoxy heater to the nickel surface for deicing. The only thermal barrier is a layer of bare epoxy coated under the nickel to prevent electrical shorting between the GNR-epoxy composite and the nickel. 14 g of ice on this rotor blade segment melted off the blade in 15 minutes. If the blade had been spinning, centrifugal force would have immediately removed the ice once an underlayer of water formed, thus greatly reducing the time for ice removal.

[00155] The resistance across the composite was 34 Ω. The applied voltage was 45 V. The current was 1.3 A. The power was 44 W. The heated area was -20.3 x 5.1 cm . The atmosphere was held at -20 °C. The ice was formed on the rotor blade surface by first adding dry ice to the Styrofoam box until it reached - 20 °C and stabilized. This was followed by spraying of cold de-ionized water from a wash bottle to result in a frozen layer of 14 g of ice on the rotor blade segment.

[00156] Example 2. Coating of steel reinforced aluminum conductors with graphene nanoribbon layers [00157] In this Example, Applicants illustrate the coating of steel reinforced aluminum conductors with a graphene nanoribbon layer for anti-icing and de-icing purposes. The uncoated steel reinforced aluminum conductor is shown in FIG. 7A. The coated steel reinforced aluminum conductor is shown in FIG. 7B. Graphene nanoribbon layers can cover the strand in the last layer only or all strands in conducting wires.

[00158] Additional structures are shown in FIGS. 7C-E. For instance, FIG. 7C shows a graphene nanoribbon layer can form on a helically wound surface that has a ribbon like structure, where the graphene nanoribbon layer is on the outer surface of the ribbon. The surface can be any stable dielectric or metal foil, such as a non ferromagnetic foil. The advantage of such a structure is the possibility of heating the wire surface in any damaging weather conditions.

[00159] Pictures of a power cable (FIG. 7D), its cross section (FIG. 7E) and its internal current distribution (FIG. 7F) are also shown. According to estimated calculations, the magnetic field induced by the current can penetrate the outside shielding layers. This field intensity would be enough to induce electrical current inside the graphene nanoribbon layer on the outer shell surface. Accordingly, the graphene nanoribbon layer is heated to melt the ice on its surface. No additional power supply is required. Moreover, the hydrophobicity of the graphene nanoribbon layer helps avoid the formation of ice on the surface.

[00160] The approximate magnetic field strength on the surface of the steel reinforced aluminum conductor (or any other good conducting wire) can be characterized with the following formula

(eq. 1):

[00161] Here, H is the strength of magnetic field and D is the diameter of the wire in meters.

[00162] Large transmission lines in use generally have a rating of over 4,000 A per circuit. However, the average current in a typical circuit is about 700 A. The magnetic field strength around the wire of typical transmission lines calculated according to Eq. 1 is shown in the plots in FIGS. 8A-B.

[00163] As illustrated in the following formula (Eq. 2), a graphene nanoribbon layer can be considered as the superposition of multiple wires:

[00164] Here, N is the number of wire that is equivalent to a single layer of a graphene nanoribbon layer and d is the layer thickness.

[00165] In addition, the current in the graphene nanoribbon layer can be characterized by the following formula (Eq. 3):

Eq. 3

GNR - Π— - tt

N

[00166] Eq. 3 represents the current induced by the magnetic field from Eq. 1.

[00167] The power loss in the graphene nanoribbon layer per unit length can be characterized with the following formula (Eq. 4):

^Ploss - ^N * ( )

[00168] Here, RGNR is the graphene nanoribbon resistance in Ohms.

[00169] The power carried by line per unit length of a transmission line can be characterized by the following formula (eq. 5): l*R Eq. 5

line

[00170] Here, Rline is the power line resistance in Ohms.

[00171] The relative loss in the graphene nanoribbon layer can be characterized by the following formula (Eq. 6):

yloss _ ^{1 Eq' 6}

pline ^{π R}lins

[00172] Data related to the characterization of graphene nanoribbon layers on transmission lines are shown in FIGS. 9A-B. FIG. 9A shows that graphene nanoribbon layers provide sufficient heat power to melt ice under many weather conditions. Likewise, FIG. 9B shows that the heat loss of graphene nanoribbon layers was less than 0.01% of the power.

[00173] Example 3. Fabrication of various graphene nanoribbon films as anti-icing and de- icing compositions

[00174] In this Example, Applicants describe the fabrication and characterization of various graphene nanoribbon films as anti-icing and de-icing compositions. The fabricated films include hexadecyl-functionalized graphene nanoribbon films (HD-GNRs), and poly(N-vinylformamide) functionalized graphene nanoribbon films (PVF-GNRs).

[00175] Example 3.1. Films prepared by HD-GNRs in CHCI3

[00176] CHCI₃ was utilized as the solvent to disperse HD-GNRs. CHCI₃ was selected due to its low boiling point of 61.2 °C, which was easier and faster for the spray coating procedure. The concentration of HD-GNRs in CHCI₃ was about 0.5 mg/mL. The temperature for spray coating was about 90 °C. [00177] Polyimide (PI) films were used as the substrates (FIG. 10A). Because the film was not robust enough in this Example, polyurethane (PU) was added in the middle to support the HD- GNRs on top (FIG. 10B). Sheet resistance (R_s) and contact angle values are summarized in Table 1.

Table 1. Contact angles of films using 0.5 mg/mL HD-GNRs in CHC1₃.

[00178] Sample a in Table 1 was superhydrophobic with a contact angle of 160° (i.e., larger than 150°). However, a sharp decrease of 62° in contact angle was found when the PU layer was added, which was thought to result from two problems. One problem was that the concentration of HD-GNRs in CHC1₃ was not high enough so that only a small area of the film could be covered by the hydrophobic HD-GNRs. The other problem was that CHC1₃ might be a good solvent for PU, which made the surface of PU dissolved and reorganized when spray coating the top layer of HD-GNRs. HD-GNRs could thus sink in the PU layer which exposed a certain area of PU on top. Therefore, a solvent with less solubility of PU and better dispersion of HD-GNRs was needed to replace CHC1₃.

[00179] Example 3.2. Films prepared by HD-GNRs in ODCB

[00180] Orthodichlorobenzene (ODCB) showed better dispersion of HD-GNRs than CHC1₃. The concentration of HD-GNRs could reach 1 mg/mL, which was helpful to obtain more uniform films in a shorter time. Moreover, the solubility of PU in ODCB was no better than that in CHC1₃. As a result, ODCB was used instead of CHC1₃ to disperse HD-GNRs at 1 mg/mL. The formed solution was then sprayed coated at 210 °C, since the boiling point of ODCB was 180.5 °C (much higher than CHC1₃)_. [00181] The two different kinds of films shown in FIGS. 10A-B were made. The first film (as shown in FIG. 10A) only contained an HD-GNR layer on top of PL The second film (as shown in FIG. 10B) had an additional PU layer in between to make the film robust.

[00182] Example 3.3. Fabrication of PI/HD-GNRs films

[00183] The thickness of HD-GNR films without a supporting layer was controlled in order to study the dependence of the contact angle on sheet resistance (or thickness). The results are shown in FIG. 11. The concentration of the HD-GNRs solution was 0.5 mg/mL. The contact angle reached a maximum sheet resistance of 500 Ω/α. With the sheet resistance further decreasing, the contact angle began to drop. The best contact angle was 149°, which was almost superhydrophobic .

[00184] Thereafter, the concentration of HD-GNRs in ODCB was increased to 1.0 mg/mL. As shown in Table 2, the contact angle was observed to increase faster with the decreasing sheet resistance and reach a plateau when the sheet resistance was below 704 Ω/α. A peak value of 152° was also shown, which demonstrated superhydrophobicity.

Table 2. Contact angles of films using 1.0 mg/mL HD-GNRs in ODCB. [00185] Example 3.4. Fabrication of PVF-GNR films

[00186] In this Example, poly(N-vinylformamide) functionalized graphene nanoribbon films (PVF-GNRs) were fabricated from a composition that included a concentration of 0.5 mg/mL of PVF-GNRs in ODCB. The relationship between contact angle and sheet resistance is shown in FIG. 12. Compared to HD-GNRs, PVF-GNRs produced a smaller contact angle, which was probably caused by less hydrophobicity of the poly(N-vinylformaide) chains than the hexadecyl chains. This phenomenon demonstrated the influence of side chain's hydrophobicity on a GNR film' s contact angles.

[00187] Example 3.5. Fabrication of PU supported HD-GNR films

[00188] In this Example, a PU layer was introduced to improve the robustness of PI/HD-GNR films. The resulting structure was previously illustrated as PI/PU/HD-GNRs in FIG. 10B. A PI/HD-GNR film with similar sheet resistance was also prepared for comparison. The data in Table 3 showed a slight decrease of 9° in contact angle, which was smaller than the case of using CHCI₃ dispersed HD-GNRs but still significant. Without being bound by theory, it is envisioned that the sinking of HD-GNRs in the PU layer may have contributed to the contact angle decrease.

Table 3. Contact angles of films prepared by 1.0 mg/mL HD-GNRs in ODCB.

[00189] To avoid the sinking of HD-GNRs into the supporting PU layer, HD-GNRs were added to the PU layer. As such, the surface of the supporting PU layer could prevent the top layer of HD-GNRs from sinking in. The structure is illustrated as PI/(PU+HD-GNRs)/HD-GNRs in FIG. 13. [00190] First, PI/(PU+HD-GNRs) films were made without the pure HD-GNRs layer on top, in order to test the hydrophobicity and robustness of the (PU+HD-GNRs) mixture layer. The ODCB solution with 1.0 mg/mL HD-GNRs contained 1 vol of PU. The largest contact angle was 106° when sheet resistance was 334 Ω/α, though the film was robust. When the amount of PU was reduced to 0.2 vol , the contact angles went up (FIG. 14). However, the films were not as robust.

[00191] As there was another pure HD-GNRs layer to be coated on top, a mixture layer with higher robustness (i.e., a higher amount of PU) was selected as the supporting layer. The amount of PU in the mixture was increased to 5 vol to guarantee the robustness of the film. The top layer was made from spray coating ODCB solution with 1.0 mg/mL HD-GNRs at 210 °C. However, the contact angle was not increased. The results are summarized in Table 4.

Table 4. Contact angles of PU supported films.

[00192] Example 3.6. Fabrication of LR/HD-GNR and PS/HD-GNR films

[00193] In this Example, Applicants demonstrate the fabrication of liquid rubber (LR) and polystyrene (PS) supported HD-GNRs films (LR/HD-GNR and PS/HD-GNR films, respectively). In particular, Applicants replaced PU with other supporting materials that were more hydrophobic, since the supporting layer would eventually be exposed to some extent. A commercial liquid rubber sealant was selected as one alternative. The solvent in the liquid rubber was a mixture of toluene and various liquid petroleum gases, which implied the hydrophobic property of the solute. The mixture was diluted in CHC1₃ at 5 wt and spray coated onto a PI substrate at 90 °C, followed by spray coating of HD-GNRs (1 mg/mL in ODCB) at 210 °C. The structure of the film is abbreviated as PI/LR/HD-GNRs and shown in FIG. 15. With a sheet resistance of 143 Ω/α, the contact angle was around 150°, which was hydrophobic. Moreover, the film was considerably robust.

[00194] In addition, PI/(LR+HD-GNRs) films and PI/(PS+HD-GNRs) films were prepared. These films exhibited higher robustness. The amounts of LR and PS were both 1 wt in ODCB solutions with 1.0 mg/mL HD-GNRs. Contact angles of PI/(LR+HD-GNRs) films were less than 90°, even when sheet resistance reached as low as 148 Ω/α. PI/(PS+HD-GNRs) films also had contact angles lower than 150° (FIG. 16).

[00195] Example 3.7. Discussion

[00196] Applicants obtained the best results by the use of PI/LR/HD-GNR films. Such films had a contact angle of around 150° and acceptable robustness at room temperature.

[00197] Example 4. Interplay of super hydrophobic and icephobic surfaces for anti-icing and de-icing applications

[00198] In this Example, Applicants demonstrate a simple and large-area processable method to create a superhydrophobic surface on different substrates that have both capabilities of anti-icing and de-icing by using perfluorododecylated graphene nanoribbons (FDO-GNRs) and lubricating liquid (heptacosafluorotributylamine) under extreme temperatures (i.e., -32 °C). Double-sided adhesive tapes were used to enhance the robustness of the films while the superhydrophobic property was unaffected. In fact, the films in this Example showed extreme water repellence with contact angles of >160° and anti-icing capability by observing water droplets roll off the film above the film temperature of -14 °C and an environment temperature of -32 °C.

[00199] Applicants also found that ice-cold water droplets would not stick onto the surperhydrophobic surface if the surface temperature was kept above -14 °C via resistive heating. On the other hand, when a fluorinated lubricating liquid was applied to switch the anti-icing surface into the de-icing mode, the ice quickly started to mobilize by gravity when the ice at the interface was melted by resistive heating. The advantages of such a superhydrophobic surface are switchable surfaces, high energy efficiency and easy preparation. [00200] Example 4.1. Synthesis of FDO-GNRs

[00201] The scheme for the synthesis of FDO-GNRs is illustrated in FIG. 17. Multi-walled carbon nanotubes (MWCNTs) were converted to graphene nanoribbons (GNRs) by splitting with a Na/K alloy. Such methods were described previously by Applicants. See, e.g., ACS Nano 2010, 4, 2059-2069. Also see ACS Nano 2011, 5, 968-974. Thereafter, the formed GNRs were functionalized by 1-iodo-perfluorododecane to form FDO-GNR. The same protocol was also utilized to form perfluorooctylated GNRs (FO-GNRs) and perfluorodecylated GNR (FD-GNRs).

[00202] Example 4.2. Fabrication of FDO-GNR films

[00203] The formed FDO-GNRs were dispersed in CHC1₃ by ultrasonication for 30 minutes. Thereafter, a double-sided tape was placed on a glass substrate. Next, the FDO-GNR solution was spray coated on top of the tapes at a temperature of about 90 °C. Colloidal silver was pasted on both ends of the film and dried at 70 °C for 15 minutes.

[00204] Example 4.3. Characterization of FDO-GNR films

[00205] Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy were utilized to characterize the formed FDO-GNR films. In addition, static water contact angles on the FDO-GNR films were measured with a goniometer by dropping water onto the films.

[00206] Example 4.4. Anti-icing test of FDO-GNR films

[00207] To test the anti-icing effects of the FDO-GNR films, the environment was maintained at a temperature of about -32 °C. Thereafter, voltage was applied to heat the films to different temperatures. Next, the films were tilted at 45° and water was dropped onto the films.

[00208] Example 4.5. Resistive heating of FDO-GNR films

[00209] The resistive heating of FDO-GNR films was conducted while the FDO-GNR films were maintained at an environmental temperature of -32 °C. Different voltages were applied to the FDO-GNR films. The temperature of the film was then measured. In addition, mist was spray-coated onto the films at -32 °C.

[00210] Example 4.6. De-icing tests of FDO-GNR films

[00211] To test the de-icing effects of the FDO-GNR films, water was dropped onto the films at -32 °C to form ice. Next, resistive heating was applied to melt the ice while the film was tilted at 45°.

[00212] The same protocol was utilized for the de-icing tests of FDO-GNR films with lubricating liquid. In particular, water was dropped onto the films at -32 °C to form ice. Next, a lubricating liquid was dropped onto the film before or after the first step. Next, resistive heating was applied to melt the ice while the film was tilted at 45°.

[00213] Example 4.7. Experimental results

[00214] The correlation between sheet resistance and static water contact angle for various GNR films (including FDO-GNR films) are shown in FIG. 18. The results indicate that higher superhydrophobicity can be achieved when the length of fluorinated chains on a GNR film is increased. The effect of fluorinated groups on superhydrophobicity was also demonstrated by comparing the FDO-GNR films with non-fluorinated hexadecyl groups.

[00215] Data relating the anti-icing test and resistive heating test of FDO-GNR films supported by double-sided tape are summarized in FIG. 19. A contact angle (161°) image of the FDO- GNR film supported by double-sided tape is shown in FIG. 19A. A photograph of the film at - 14 °C before water (0 °C) was dropped onto the surface is shown in FIG. 19B. A photograph of the film at -14 °C after water (0 °C) was rolled off the surface is shown in FIG. 19C. No significant changes of the film were observed. Moreover, no water droplets were attached to the surface. [00216] A chart correlating resistive heating intensity and film temperature is shown in FIG. 19D. The environmental temperature was at -32 °C. The film reached room temperature with a resistive heating intensity of -0.2 W-cm^" .

[00217] FIG. 19E shows a photograph of the film that was kept at 30 °C by resistive heating after spraying water (0 °C, 25 mL) onto the surface within 10 minutes (environmental temperature: -32 °C). FIG. 19F shows a photograph of the film at -32 °C after spraying water (0 °C, 25 mL) onto the surface within 10 minutes (environmental temperature: -32 °C).

[00218] Overall, the aforementioned results indicate that the FDO-GNR films prevented ice formation due to resistive heating. In addition, Applicants observed only a small amount of water attached to the edges due to superhydrophobicity.

[00219] The results of de-icing tests performed on FDO-GNR films supported by double-sided tapes are summarized in FIG. 20. FIGS. 20A-B show photographs of the FDO-GNR films without lubricating liquids. Ice particles were observed before de-icing (FIG. 20A). After de- icing for 90 seconds with a resistive heating intensity of ~ 0.2 W-cm^" , the ice particles melted while the water was retained on the surface (FIG. 20B). FIGS. 20C-D show photographs of the FDO-GNR films with lubricating liquids. Ice particles were observed before de-icing (FIG. 20C). After de-icing for 90 seconds with a resistive heating intensity of ~ 0.2 W-cm^"2, the ice particles fell off of the surface when the film was tilted (FIG. 20D).

[00220] Without being bound by theory, it is envisioned that superhydrophobicity of the FDO- GNR films resulted from the surface roughness of FDO-GNR bundles. For instance, the SEM image of FDO-GNR films showed a percolating network of GNR bundles that created surface roughness (FIG. 21A). Likewise, the Raman spectrum of FDO-GNRs indicated the formation of thick multilayered graphene that helped to form structural hierarchy (FIG. 21B).

[00221] Without being bound by further theory, Applicants also envision that the chemical structures of the perfluoroalkylated chains of the FDO-GNRs contributed to the superhydrophobicity of the films. The X-ray photoelectron spectroscopy (XPS) data of a FDO- GNR film is shown in FIG. 22. The peak in FIG. 22A indicates the formation of sp²-C (284.50 eV) and CF₂ (-291.50 eV). Likewise, the peak in FIG. 22B shows a small amount of oxygen in graphene. In addition, the Fls peak in FIG. 22C proved that the functionalization of perfluorododecyl groups was successful. The C/O/F ratio of the FDO-GNR films was 84.3/12.1/3.6.

[00222] In addition, as demonstrated in FIG. 20, Applicants envision that the addition of lubricants to FDO-GNR films can contribute to their de-icing effects. Additional support for this observation is also provided in FIG. 23, which shows a de-icing test of FDO-GNR films, in which lubricating liquid was added after ice formation. The ice particles remained on the FDO- GNR films before de-icing (FIG. 23A). However, after de-icing for 30 seconds with resistive heating intensity of -0.2 W-cm^"2 _; ice rolled off before it completely melted (FIG. 23B).

[00223] In summary, Applicants have prepared robust superhydrophobic films that are capable of both anti-icing and de-icing activities. As for the passive anti-icing strategy, freezing of incoming water is well prevented at -14 °C on the surface. With a low resistive heating intensity of 0.2 W-cm^" , the surface of the film could stay at room temperature while the environmental temperature decreases to -32 °C. Lubricating liquid could further enhance de-icing capability and energy efficiency since the removal of ice only requires melting the ice at the interface. The ease of the spray-coating method enables it to be utilized on a variety of substrates and devices, and anti-icing and de-icing applications are expected to be practical in extreme environments.

[00224] Example 5. Fabrication of de-icing/anti-icing bubble wraps for various surfaces

[00225] In this Example, Applicants demonstrate the fabrication of various bubble wraps that are coated with the graphene nanoribbon layers of the present disclosure (hereinafter "GNR coated bubble wraps"). The coated bubble wraps can be utilized as de-icing and anti-icing shields for various structures, such as radomes. Furthermore, the coated bubble wraps are RF transparent, icephobic, and light weight. Moreover, de-icing can occur at low operation costs without requiring heat power. In addition, the coated bubble wraps can be placed on various structures (e.g., radome surfaces) in a cost effective and efficient manner. [00226] It is envisioned that the super hydrophobic graphene nanoribbon layers on the bubble wraps reduces the creep rate of ice and diminishes the energy required for ice removal. Likewise, the bubble wrap structure provides effective water drop and ice removal. Cyclical shaking, movement, and scrolling can also be utilized to blow off water, snow and ice particles from the bubble wraps.

[00227] In this example, ethylene tetrafluoroethylene (ETFE) was utilized as the source of the bubble wraps. ETFE provides advantages in manufacturing, maintenance, installation, electric power consumption, weight and cost. For instance, ETFE is strong enough to bear 400 times its own weight. Likewise, ETFE can be stretched to three times its length without loss of elasticity. ETFE can also be repaired by welding patches over tears. In addition, ETFE has a nonstick surface that resists dirt. ETFE is also expected to last as long as 50 years. Furthermore, ETFE is usually applied in several layers that can be inflated. ETFE also demonstrates optical and RF transparencies.

[00228] FIG. 24 provides images and illustrations of how one can place GNR coated bubble wraps on a radome. An image of a radome is shown in FIG. 24A. FIG. 24B shows the image of a radome 30 covered with a GNR coated bubble wrap 31, which contains multiple bubble wraps 32 on radome surface 34. The GNR coated bubble wrap 31 is supported by plurality of trusses secured firmly on the top of the must. These trusses can be used to shake and move the low weight and durable GNR coated bubble wrap up and down to dislodge ice from the radome surface, or scroll the structure up and down like a curtain. Because of the hydrophobic nature of the GNR coated bubble wraps, the force required for such dislodge is very low.

[00229] An image of a deflated GNR coated bubble wrap can be represented by FIG. 24C. The deflated versions can be conveniently packaged for ground transportation. An additional image of a radome along with calculations of the heated areas is shown in FIG. 24D.

[00230] Example 5.1. Fabrication and advantages of GNR coated bubble wraps [00231] A two-step method can be utilized to produce GNR coated bubble wraps. First, ETFE is utilized to make the bubble wraps. Next, the ETFE bubble wraps are spray-coated with graphene nanoribbons to form super hydrophobic GNR coated bubble wraps.

[00232] Thermal bonding can be utilized to weld ETFE into bubble wraps. The welding temperature can reach 300°C, which can ensure that the welding effect is strong and durable. An exemplary welding apparatus is shown in FIG. 25A. Another example of a welding apparatus is shown in FIG. 25B. An image of a formed ETFE bubble wrap is shown in FIG. 25C.

[00233] Layer spraying can be utilized to spray graphene nanoribbons onto the bubble wrap surfaces to form GNR coated bubble wraps. As illustrated in FIG. 25D, multiple nozzles from an apparatus can be utilized to spray-coat the bubble wrap surfaces. Graphene nanoribbon layers with various thicknesses (e.g., 20-40 nm) can then form on the ETFE bubble wraps.

[00234] The measured contact angle of graphene nanoribbons is about 130-140 degrees. Therefore, the graphene nanoribbon layers of the GNR coated bubble wraps are very close to being super hydrophobic (i.e., contact angles of more than 150 degrees). This is advantageous because it has been found that water droplets impacting super hydrophobic surfaces have a limited contact time with the surface that reduces the energy needed to detach a drop of water from a surface. Even under ice-forming conditions, droplets impinging cold super hydrophobic substrates bounce off the surface before freezing can occur.

[00235] All the required materials for the aforementioned fabrication methods are low cost, low weight, and in mass production. For instance, one ETFE layer generally costs about $30/m² . Since three GNR coated bubble wraps preferably cover a surface area of about 300m , the bubble wrap material costs about $9,000.

[00236] Furthermore, the costs of coating the bubble wraps with a graphene nanoribbon layer that has a thickness of about 20-40 nm should not exceed $1,000. For example, a 100 m² graphene nanoribbon coating of 100 nm thickness requires less than 100 grams of graphene nanoribbons with a cost of about $100. [00237] Moreover, manufacturing of GNR coated bubble wraps can occur in an expedited manner. For instance, such manufacturing can be completed in less than two months.

[00238] Moreover, no additional power supplies on sites are required for the operation of the GNR coated bubble wraps. Therefore, the GNR coated bubble wraps in this Example can be fabricated and operated in a very cost effective manner.

[00239] The utilization of the bubble wraps in this Example also provides numerous advantages. For instance, ETFE-based materials are chemically inert, fire resistant, and insensitive to UV radiation. ETFE-based materials also have high corrosion resistance and strength over a wide temperature range, low dielectric constant and dissipation factor, and a high melting temperature. Moreover, such materials have self-cleaning properties, where the exposed surfaces can be cleaned through rain. Such attributes guarantee extreme durability without losing performance in conditions ranging from equatorial areas to higher latitudes, virtually from -190°C to +150°C. Moreover, ETFE-based materials have the ability to adapt to the shape of a structure while being optically and RF transparent.

[00240] Additional advantages of the graphene nanoribbon coated bubble wraps include, without limitation, the following: (1) optimal RF transparency with no impact on radar performance, especially noise figure, range reduction, range and direction accuracy estimation; (2) optimal thermal stability; (3) optimal UV radiation stability; (4) oleophobic surfaces; (5) chemical resistance; (6) antistatic surfaces; (7) extreme mechanical wear resistance; (8) unlimited lifetime; (9) optimal weather and erosion resistance; (10) environmentally benign; (11) convenient application of GNR coatings (e.g., by either spray or brush); and (12) facile curing in natural environments.

[00241] As such, the GNR coated bubble wraps can find applications on many surfaces.

Examples of such surfaces are shown in FIGS. 25E-H.

[00242] Example 5.2. Characterization of GNR-coated ETFE surfaces [00243] In this Example, Applicants compare the hydrophobicity of GNR-coated ETFE surfaces with un-coated ETFE surfaces. As illustrated in FIG. 26A, the creep rate of water or ice on a material surface is characterized by contact angle. On a surface with high (>90°) contact angle, a water droplet would not touch large areas of the surface. As such, the shape of the droplet would be close to spherical. Therefore, the energy required for the removal of water, snow or ice from the surface would diminish as the contact angle increases.

[00244] Based on the literature, the ETFE contact angle (Θ) is estimated to be about 90°- 100°. Based on various calculations, the contact angle of a GNR coating on an ETFE surface is about 147°. The water adhesion energy is proportional to (1+ cos Θ). For ETFE, this coefficient is about 1. For GNR-coated ETFE, this coefficient is about 0.161329. Therefore, the coating of an ETFE surface with a GNR layer significantly lowers the required energy for the removal of water from the layer.

[00245] It was observed that the water droplets did not stick to a GNR-coated ETFE surface below the water freezing temperature. Rather, the water bounced off of the surface. Thus, the ability of a superhydrophobic surface to bounce off incoming droplets reduces the time of contact with the solid. Accordingly, there is not enough time for water droplets to freeze. Such weak adhesion with the solid substrate and the ability to repel incoming droplets significantly reduces the ice accumulation on the GNR-coated ETFE surface. See Hejazi et al., Scientific Reports, 3, Article No. 2194 (2013).

[00246] The pillow shape of the GNR-coated bubble wraps is also important for proper anti- icing performance. Because of the tilt in the structure, a water droplet with a certain weight begins to slide down the inclined structure more effectively (FIG. 26B).

[00247] The plots in FIG. 26C (from Masashi et al., Langmuir 2000, 16, 5754-5760) shows the sliding angle over the contact angle for several different materials. The test (points) and simulation (solid line) results for contact angle regions range from 145° to 156°. According to this plot, the sliding angle for GNRs is around 50°. Therefore, the bubble inflation is a preferred method of increasing the probability of water sliding down a GNR-coated layer. [00248] However, there may be instances where the combination of super hydrophobicity and sliding may not be enough to remove ice accumulation from a tilted surface. For instance, it has been shown that rain droplets can stick even to super hydrophobic surfaces and then freeze, thereby leading to ice accumulation. See, e.g., ACS Nano, 2012, 6 (8), pp 6536-6540.

[00249] The strength of ice adhesion on hydrophobic GNR surfaces can also depend on the contact angle hysteresis (CAH), as shown in FIG. 26D. See Hejazi et al., Scientific Reports, 3, Article No. 2194 (2013). The red spots correspond to superhydrophobic materials with CAH similar to GNRs (inside the blue oval). The difference between advancing and receding contact angles defines the CAH.

[00250] Gravity pulls on water droplets to move them down, while CAH keeps the droplet in place. As a result, the droplets may become asymmetric in some instances and not move on a vertical and super hydrophobic surface. Consequently, the water may freeze and lead to ice accumulation on the surface.

[00251] A typical fractured ice structure on a bubbled surface is shown in FIG. 26E. As illustrated, the ice layer consists of a plurality of small ice pieces with low adhesion. As such, these small ice pieces can be easily displaced by shaking and agitation.

[00252] Without further elaboration, it is believed that one skilled in the art can, using the description herein, utilize the present disclosure to its fullest extent. The embodiments described herein are to be construed as illustrative and not as constraining the remainder of the disclosure in any way whatsoever. While the embodiments have been shown and described, many variations and modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. Accordingly, the scope of protection is not limited by the description set out above, but is only limited by the claims, including all equivalents of the subject matter of the claims. The disclosures of all patents, patent applications and publications cited herein are hereby incorporated herein by reference, to the extent that they provide procedural or other details consistent with and supplementary to those set forth herein.

Claims

WHAT IS CLAIMED IS:

1. A method of preventing or reducing ice formation on a surface, wherein the method comprises:

applying a composition to the surface,

wherein the composition comprises graphene nanoribbons; and

wherein the composition forms a layer associated with the surface.

2. The method of claim 1, wherein the composition is applied to the surface by a method selected from the group consisting of chemical vapor deposition, spraying, spray-coating, sputtering, coating, spin coating, blade coating, rod coating, film coating, printing, painting, brushing, mechanical transfer, annealing, and combinations thereof.

3. The method of claim 1, wherein the graphene nanoribbons are selected from the group consisting of functionalized graphene nanoribbons, pristine graphene nanoribbons, doped graphene nanoribbons, mixtures of graphene nanoribbons and carbon nanotubes, graphene oxide nanoribbons, reduced graphene oxide nanoribbons, and combinations thereof.

4. The method of claim 1, wherein the graphene nanoribbons comprise mixtures of graphene nanoribbons and carbon nanotubes, wherein the carbon nanotubes comprise multi-walled carbon nanotubes.

5. The method of claim 1, wherein the graphene nanoribbons are functionalized with a plurality of functional groups.

6. The method of claim 1, wherein the functional groups are selected from the group consisting of halogenated groups, fluorinated groups, hydrophobic groups, alkyl groups, halogenated alkyl groups, fluorinated alkyl groups, hydrophobic alkyl groups, and combinations thereof.

7. The method of claim 1, wherein the graphene nanoribbons were derived from split multiwalled carbon nanotubes.

8. The method of claim 1, wherein the graphene nanoribbons comprise a single layer.

9. The method of claim 1, wherein the graphene nanoribbons comprise a plurality of layers.

10. The method of claim 1, wherein the graphene nanoribbons comprise from about 2 layers to about 10 layers.

11. The method of claim 1, wherein the graphene nanoribbons comprise widths ranging from about 75 nm to about 750 nm.

12. The method of claim 1, wherein the graphene nanoribbons comprise widths ranging from about 250 nm to about 350 nm.

13. The method of claim 1, wherein the graphene nanoribbons comprise lengths ranging from about 10 μιη to about 100 μιη.

14. The method of claim 1, wherein the graphene nanoribbons comprise lengths ranging from about 10 μιη to about 50 μιη.

15. The method of claim 1, wherein the graphene nanoribbons comprise length-to- width aspect ratios that range from about 100 to about 150.

16. The method of claim 1, wherein the graphene nanoribbons comprise length-to- width aspect ratios of about 140.

17. The method of claim 1, wherein the composition is fabricated by:

splitting carbon nanotubes to form graphene nanoribbons; and

mixing graphene nanoribbons with functional groups to form functionalized graphene nanoribbons.

18. The method of claim 1, wherein the composition further comprises a polymer.

19. The method of claim 18, wherein the polymer is selected from the group consisting of epoxy polymers, polyepoxides, polyimides, polyethereimides, polylactic acids, polyglycolic acids, polylactones, polyamines, polyacrylates, polycyanoacrylates, polystyrenes, polybutadienes, polyurethane, epoxy resins, nylons, polyesters, acrylic resins, hydrogenated nitrile, butadiene rubbers, synthetic rubbers, natural rubbers, and combinations thereof.

20. The method of claim 1, wherein the composition is fabricated by:

mixing graphene nanoribbons with monomers to form a mixture; and

curing the mixture to form the composition.

21. The method of claim 1, wherein the composition further comprises a ceramic material.

22. The method of claim 21, wherein the ceramic material is selected from the group consisting of crystalline ceramics, non-crystalline ceramics, metals, metal oxides, metal carbides, transition metals, transition metal oxides, transition metal carbides, metalloids, and combinations thereof.

23. The method of claim 1, wherein the composition is in the form of a liquid.

24. The method of claim 1, wherein the composition is in the form of a solid.

25. The method of claim 1, wherein the layer is formed on the surface.

26. The method of claim 1, wherein the layer is formed within the surface.

27. The method of claim 1, wherein the layer has a thickness ranging from about 1 nm to about 100 μπι.

28. The method of claim 1, wherein the layer has a thickness of between about 10 nm to about 100 nm.

29. The method of claim 1, wherein the layer is hydrophobic.

30. The method of claim 1, wherein the contact angle between the layer and water ranges from about 100 degrees to about 160 degrees.

31. The method of claim 1, wherein the contact angle between the layer and water is more than about 150 degrees.

32. The method of claim 1, wherein the layer has a conductivity ranging from about 10^"5 S/m to about 500 S/m.

33. The method of claim 1, wherein the layer has a conductivity of more than about 100 S/m.

34. The method of claim 1, wherein the layer has a resistance ranging from about 1 Ω/sq to about 1000 Ω/ sq.

35. The method of claim 1, wherein the layer has a resistance of less than about 500 Ω/sq.

36. The method of claim 1, wherein the layer has a resistance of about 1 Ω/sq.

37. The method of claim 1, wherein the layer comprises a polymer matrix, wherein the graphene nanoribbons are dispersed within the polymer matrix.

38. The method of claim 1, wherein the graphene nanoribbons associated with the layer comprise a network of graphene nanoribbons.

39. The method of claim 38, wherein the graphene nanoribbon network defines an electrical pathway within the layer.

40. The method of claim 1, wherein the graphene nanoribbons constitute from about 0.1 wt to about 10 wt of the layer.

41. The method of claim 1, wherein the graphene nanoribbons constitute less than about 5 wt of the layer.

42. The method of claim 1, wherein the layer further comprises a lubricant, wherein the lubricant is positioned above the layer.

43. The method of claim 1, wherein the surface is selected from the group consisting of wire surfaces, transmission line surfaces, radome surfaces, window surfaces, automobile surfaces, aircraft surfaces, ship surfaces, building surfaces, antenna surfaces, radar surfaces, solar panel surfaces, solar plant surfaces, wind turbine surfaces, radiofrequency equipment surfaces, mat surfaces, blanket surfaces, wrapping surfaces, tape surfaces, glass-based surfaces, quartz-based surfaces, alumina-based surfaces, silicon-based surfaces, plastic -based surfaces, polymer-based surfaces, electrically conductive surfaces, and combinations thereof.

44. The method of claim 1, wherein the surface comprises a wire selected from the group consisting of power lines, cables, reinforced cables, power cables, conductors, transmission lines, foils, metal foils, dielectric foils, and combinations thereof.

45. The method of claim 1, wherein the surface is near an electrically conductive structure, wherein voltage applied through the electrically conductive structure produces a magnetic field, wherein the magnetic field induces a current in the layer, and wherein the induced current causes the layer to heat.

46. The method of claim 45, wherein the electrically conductive structure is a wire associated with the surface.

47. The method of claim 45, wherein the electrically conductive structure has a current greater than about 100 Amps.

48. The method of claim 45, wherein the electrically conductive structure has a current between about 100 Amps and about 200 Amps.

49. The method of claim 1, wherein the surface further comprises an adhesive layer, wherein the adhesive layer is positioned between the surface and the layer.

50. The method of claim 1, wherein the layer prevents and reduces ice formation on the surface.

51. The method of claim 1, wherein the ice is selected from the group consisting of ice particles, frost, snow, sleet, hail, and combinations thereof.

52. The method of claim 1, wherein the layer prevents ice formation by repulsion of water from the layer.

53. The method of claim 1, wherein the layer reduces ice formation by melting the ice from the surface.

54. The method of claim 53, wherein the melting comprises applying a voltage to the layer, wherein the application of voltage to the layer results in the heating of the surface.

55. The method of claim 54, wherein the voltage is applied from an external voltage source that is separate and apart from the surface.

56. The method of claim 54, wherein the voltage is applied through an electrically conductive structure near the surface, wherein the applied voltage produces a magnetic field , wherein the magnetic field induces a current in the layer, and wherein the induced current causes the layer to heat.

57. The method of claim 56, wherein the electrically conductive structure is a wire associated with the surface.

58. The method of claim 56, wherein the electrically conductive structure has a current greater than about 100 Amps.

59. The method of claim 56, wherein the electrically conductive structure has a current between about 100 Amps and about 200 Amps.

60. The method of claim 1, wherein the layer prevents or reduces ice formation at environmental temperatures below 0 °C.

61. The method of claim 1, wherein the layer prevents or reduces ice formation at environmental temperatures below -30 °C.

62. A surface comprising a layer,

wherein the layer comprises a network of graphene nanoribbons that define an electrical pathway within the layer, and

wherein the layer prevents or reduces ice formation on the surface.

63. The surface of claim 62, wherein the graphene nanoribbons are selected from the group consisting of functionalized graphene nanoribbons, pristine graphene nanoribbons, doped graphene nanoribbons, mixtures of graphene nanoribbons and carbon nanotubes, graphene oxide nanoribbons, reduced graphene oxide nanoribbons, and combinations thereof.

64. The surface of claim 62, wherein the graphene nanoribbons comprise mixtures of graphene nanoribbons and carbon nanotubes, wherein the carbon nanotubes comprise multi-walled carbon nanotubes.

65. The surface of claim 62, wherein the graphene nanoribbons are functionalized with a plurality of functional groups.

66. The surface of claim 65, wherein the functional groups are selected from the group consisting of halogenated groups, fluorinated groups, hydrophobic groups, alkyl groups, halogenated alkyl groups, fluorinated alkyl groups, hydrophobic alkyl groups, and combinations thereof.

67. The surface of claim 62, wherein the graphene nanoribbons were derived from split multiwalled carbon nanotubes.

68. The surface of claim 62, wherein the graphene nanoribbons comprise a single layer.

69. The surface of claim 62, wherein the graphene nanoribbons comprise a plurality of layers.

70. The surface of claim 62, wherein the graphene nanoribbons comprise from about 2 layers to about 10 layers.

71. The surface of claim 62, wherein the graphene nanoribbons comprise widths ranging from about 75 nm to about 750 nm.

72. The surface of claim 62, wherein the graphene nanoribbons comprise widths ranging from about 250 nm to about 350 nm.

73. The surface of claim 62, wherein the graphene nanoribbons comprise lengths ranging from about 10 μιη to about 100 μιη.

74. The surface of claim 62, wherein the graphene nanoribbons comprise lengths ranging from about 10 μιη to about 50 μιη.

75. The surface of claim 62, wherein the graphene nanoribbons comprise length-to-width aspect ratios that range from about 100 to about 150.

76. The surface of claim 62, wherein the graphene nanoribbons comprise length-to-width aspect ratios of about 140.

77. The surface of claim 62, wherein the layer is on the surface.

78. The surface of claim 62, wherein the layer is within the surface.

79. The surface of claim 62, wherein the layer has a thickness ranging from about 1 nm to about 100 μπι.

80. The surface of claim 62, wherein the layer has a thickness of between about 10 nm to about 100 nm.

81. The surface of claim 62, wherein the layer is hydrophobic.

82. The surface of claim 62, wherein the contact angle between the layer and water ranges from about 100 degrees to about 160 degrees.

83. The surface of claim 62, wherein the contact angle between the layer and water is more than about 150 degrees.

84. The surface of claim 62, wherein the layer has a conductivity ranging from about 10^"5 S/m to about 500 S/m.

85. The surface of claim 62, wherein the layer has a conductivity of more than about 100 S/m.

86. The surface of claim 62, wherein the layer has a resistance ranging from about 1 Ω/sq to about 1000 Ω/ sq.

87. The surface of claim 62, wherein the layer has a resistance of less than about 500 Ω/sq.

88. The surface of claim 62, wherein the layer comprises a polymer matrix, wherein the graphene nanoribbons are dispersed within the polymer matrix.

89. The surface of claim 88, wherein the polymer in the polymer matrix is selected from the group consisting of epoxy polymers, polyepoxides, polyimides, polyethereimides, polylactic acids, polyglycolic acids, polylactones, polyamines, polyacrylates, polycyanoacrylates, polystyrenes, polybutadienes, polyurethane, epoxy resins, nylons, polyesters, acrylic resins, hydrogenated nitrile, butadiene rubbers, synthetic rubbers, natural rubbers, and combinations thereof.

90. The surface of claim 62, wherein the layer further comprises a ceramic material.

91. The surface of claim 90, wherein the ceramic material is selected from the group consisting of crystalline ceramics, non-crystalline ceramics, metals, metal oxides, metal carbides, transition metals, transition metal oxides, transition metal carbides, metalloids, and combinations thereof.

92. The surface of claim 62, wherein the graphene nanoribbons constitute from about 0.1 wt to about 10 wt of the layer.

93. The surface of claim 62, wherein the graphene nanoribbons constitute less than about 5 wt of the layer.

94. The surface of claim 62, wherein the layer further comprises a lubricant, wherein the lubricant is positioned above the layer.

95. The surface of claim 62, wherein the surface is selected from the group consisting of wire surfaces, transmission line surfaces, radome surfaces, window surfaces, automobile surfaces, aircraft surfaces, ship surfaces, building surfaces, antenna surfaces, radar surfaces, solar panel surfaces, solar plant surfaces, wind turbine surfaces, radiofrequency equipment surfaces, mat surfaces, blanket surfaces, wrapping surfaces, tape surfaces, glass-based surfaces, quartz-based surfaces, alumina-based surfaces, silicon-based surfaces, plastic -based surfaces, polymer-based surfaces, electrically conductive surfaces, and combinations thereof.

96. The surface of claim 62, wherein the surface comprises a wire selected from the group consisting of power lines, cables, reinforced cables, power cables, conductors, transmission lines, foils, metal foils, dielectric foils, and combinations thereof.

97. The surface of claim 62, wherein the surface is near an electrically conductive structure, wherein voltage applied through the electrically conductive structure produces a magnetic field , wherein the magnetic field induces a current in the layer, and wherein the induced current causes the layer to heat.

98. The surface of claim 97, wherein the electrically conductive structure is a wire associated with the surface.

99. The surface of claim 97, wherein the electrically conductive structure has a current greater than about 100 Amps.

100. The surface of claim 97, wherein the electrically conductive structure has a current between about 100 Amps and about 200 Amps.

101. The surface of claim 62, wherein the surface further comprises an adhesive layer, wherein the adhesive layer is positioned between the surface and the layer.