WO2019073317A1 - Polymer-graphene oxide triboelectric materials, methods of making and uses thereof - Google Patents

Abstract

A triboelectric-based component, method of making and use thereof is described. The triboelectric-based component can include a triboelectrically active film positioned on at least a portion of a surface of an electrode. The triboelectrically active film that include a graphene material attached to a functionalized polymer.

Description

POLYMER-GRAPHENE OXIDE TRIBOELECTRIC MATERIALS, METHODS OF

MAKING AND USES THEREOF

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of U. S. Provisional Patent Application No. 62/570,736 filed October 11, 2017, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

A. Field of the Invention

[0002] The invention generally concerns a triboelectric-based component that can include a triboelectric film positioned on at least a portion of a surface of an electrode. The triboelectric film can include graphene material attached to a functionalized polymer.

B. Description of Related Art

[0003] A clean and economically viable source of energy is desirable for global energy consumption. In this regard, harvesting energy from the ambient environment has been investigated as an alternative to conventional energy sources. By way of example, mechanical energy harvesting devices based on the triboelectric effect (triboelectric devices) can harvest various types of mechanical energy such as human motion, vibration energy, wind energy, water wave energy, air- flow energy, and sound energy. In a triboelectric device, mechanical energy can be converted into useful electrical energy by using an electrostatic induction phenomenon due to a frictional contact. Triboelectricity can be generated when materials having electron affinity different from each other are brought into contact through friction.

[0004] Materials used in triboelectric devices typically include organic materials (e.g., polytetrafluorethylene (PTFE), nylon, polydimethylsiloxane (PDMS), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), reduced graphene oxide, graphene oxide, carbon nanotubes, and the like), inorganic materials (e.g., indium tin oxide (ITO), platinum, silver, copper, titanium, titania, silicon and the like), or composites thereof. U.S. Patent No. 9,691,556 describes electrochemical devices that include graphene adhered to an organic polymer by partially dissolving the polymer with an organic solvent to physically adhere the polymer to the graphene surface. In another example, graphene can be dispersed in polymers having aromatic groups in the main chain by mixing polystyrene with appropriately modified graphite oxide (GO) followed by reduction and precipitation (See, Stankovich et.al., Nature, 2006, 442, 282-286). In yet another example, nanocomposites of reduced graphene oxide with polyvinyl alcohol have been prepared by esterifying modified polyvinyl alcohol with graphene oxide (See, Salavagione et. al, Macromolecules, 2011, 44, 2685-2692).

[0005] While various attempts to make carbon based/organic polymer composites for electrical devices have been produced, the polymer portion of these composites can suffer from inferior physical, thermal, and/or mechanical properties due to chemical and/or thermal processing conditions.

SUMMARY OF THE INVENTION

[0006] A discovery has been made that addresses at least some of the problems associated with currently available triboelectric-based materials. The discovery is premised on the idea of a triboelectrically active material that includes a graphene material attached to a functionalized polymer through covalent bonds. Such an attachment mechanism can allow for the graphene to be homogeneously dispersed and covalently attached to a polymer matrix of the functionalized polymer. Without wishing to be bound by theory, and as illustrated in a non- limiting manner in the Examples, this set-up is believed to increase the output voltage of the triboelectric material when compared with conventional triboelectrically active materials. Furthermore, the present invention also provides for an elegant and efficient process that can utilize photonic energy to prepare the triboelectrically active materials of the present invention with limited or no adverse effects on the polymer (e.g., loss of mechanical or physical properties).

[0007] In one instance of the present invention, a triboelectric-based component is described. The triboelectric-based component can include a triboelectrically active film positioned on at least a portion of a surface of an electrode. The triboelectrically active film can include a graphene material attached to a functionalized polymer matrix. Attachment can include covalently bonding the graphene material to the functionalized polymer matrix. In a preferred instance, the functionalized polymer matrix includes a linker group and the linker group is covalently bonded to the graphene material. The linker group can include sulfur atoms, oxygen atoms, nitrogen atoms, or combinations thereof, preferably sulfur and oxygen atoms. In one instance, the linker group can include sulfur and oxygen atoms and the sulfur atom can be covalently bonded to the polymer and the oxygen atom can covalently bond to the graphene material. The functionalized polymer matrix can include any known polymer, preferably a thermoplastic material (e.g., (PVC), polyvinyl dichloride (PVDC), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polycholorotrifluoroethylene (PCTFE), polytetrafluoroethylene (PTFE) or blends thereof). In a preferred instance, the polymer is PVC. In some instance, the functionalized polymer matrix can include polyvinylidene fluoride (PVDF), a PVDF copolymers, PVC, poly dimethyl siloxane (PDMS), polymethylmethacrylate, polytetrafluoroethylene, a polymer foam, poly(methylmethacrylate)-copoly(lH-lH- perfluoroctylmethyacylate), fluorinated parylenes, or blends thereof. In some instances, the graphene material includes reduced graphene oxide. The reduced graphene oxide can be derived from photonic energy reduction of graphene oxide.

[0008] In another instance of the present invention, a process to prepare a triboelectrically active material is described. The process can include applying photonic energy to a film that can include graphene oxide attached (e.g., covalently bonded) to a functionalized polymer under conditions sufficient to reduce at least a portion of the graphene oxide to reduced graphene oxide. The applied photonic energy can be at least 0.2 joules per centimeter squared (J/cm^"2), or 0.5 J/cm^"2 to 3.1 J/cm^"2 at room temperature (e.g., 20 °C to 30 °C) and pressure. In some instances, the graphene oxide attached to the functionalized polymer can be obtained by subjecting a polymer and a linker group to conditions sufficient to covalently bond the polymer to the linker group, forming a polymer/linker group material. The polymer/linker group material can be contacted with graphene oxide under conditions sufficient to covalently bond the linker group to the graphene oxide. Thus, the graphene oxide is attached to a functionalized polymer through covalent bond formation with the linker group (graphene oxide— linker group— functionalized polymer). The linker group can include an oxygen atom, a sulfur atom, a nitrogen atom, or combinations thereof. Non-limiting examples of linker groups include thiophenols, aminothiophenol, aminophenol, diamines, maleic anhydride, or blends thereof. In a preferred embodiment, the linker group can be 4-mercaptophenol and the polymer matrix can include polyvinyl chloride. In this instance, the sulfur atom of the 4-mercaptophenol (also known as 4-hydroxythiophenol) can covalently bond to the polyvinyl chloride and the oxygen atom of the 4-mecaptophenol covalently bonds to the graphene oxide. A solution that includes a solvent and graphene oxide attached to the functionalized polymer matrix can be coated on at least a portion of a surface of a substrate (e.g., electrode surface). In some instances, other polymers can be added to the solution. Non-limiting examples of other polymers are polyvinylidene fluoride (PVDF), a PVDF copolymers, PVC, polydimethylsiloxane (PDMS), polymethylmethacrylate, polytetrafluoroethylene, a polymer foam, poly(methylmethacrylate)- copoly(lH-lH-perfluoroctylmethyacylate), fluorinated parylenes, or blends thereof. Removal of the solvent from the solution can form the film on at least a portion of the surface of the substrate.

[0009] In yet another aspect of the present invention an electronic device is described. The electrical device can include a triboelectric-based component of the present invention and an integrated circuit coupled to the triboelectric-based component. The integrated circuit can be configured to read-out a user input to the triboelectric-based component. In some embodiments, the electronic device can be an energy harvester, a sensor, a mobile device, a wearable device, a flexible device, a display device, a thin film transistor (TFT), or any combination thereof. [0010] In the context of the present invention 20 embodiments are described. Embodiment 1 is a triboelectric-based component comprising a triboelectrically active film positioned on at least a portion of a surface of an electrode, the triboelectrically active film comprising a graphene material attached to a functionalized polymer. Embodiment 2 is the triboelectric- based component of embodiment 1, wherein the graphene material is covalently bonded to the functionalized polymer. Embodiment 3 is the triboelectric-based component of embodiment 2, wherein the functionalized polymer comprises a linker group, and wherein the linker group is covalently bonded to the graphene material. Embodiment 4 is the triboelectric-based component embodiment 3, wherein the linker group comprises a sulfur atom, a nitrogen atom, an oxygen atom, or combinations thereof, preferably sulfur and oxygen atoms. Embodiment 5 is the triboelectric-based component of embodiment 4, wherein the linker group comprises sulfur and oxygen atoms, and wherein the sulfur atom covalently bonds to the polymer and the oxygen atom covalently bonds to the graphene material. Embodiment 6 is the triboelectric- based component of any one of embodiments 1 to 5, wherein the functionalized polymer comprises a thermoplastic material. Embodiment 7 is the triboelectric-based component of embodiment 6, wherein the thermoplastic material is polyvinyl chloride (PVC), polyvinyl dichloride (PVDC), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polycholorotrifluoro ethylene (PCTFE), polytetrafluoroethylene (PTFE). Embodiment 8 is the triboelectric-based component of any one of embodiments 1 to 7, wherein the graphene material comprises reduced graphene oxide. Embodiment 9 is the triboelectric-based component of embodiment 8, wherein the reduced graphene oxide is derived from photonic energy reduction of graphene oxide. Embodiment 10 is the triboelectric-based component of any one of embodiments 1 to 9, wherein the triboelectric film is a blend of the graphene material and at least one of polyvinylidene fluoride (PVDF), a PVDF copolymers, polydimethylsiloxane (PDMS), PVC, polymethylmethacrylate, polytetrafluoroethylene, a polymer foam, or poly(methylmethacrylate)-copoly(lH-lH-perfluoroctylmethyacylate), a fluorinated parylene. Embodiment 11 is an electronic device comprising a triboelectric-based component of any one of embodiments 1 to 10 and an integrated circuit coupled to the triboelectric-based component and configured to read-out a user input to the triboelectric-based component. Embodiment 12 is the electronic device of embodiment 11, wherein the electronic device is an energy harvester, a sensor, a mobile device, a wearable device, a flexible device, a displays device, a thin film transistor (TFT), or any combination thereof.

[0011] Embodiment 13 is a process to produce a triboelectrically active material, the process comprising applying photonic energy to a film comprising graphene oxide attached to a functionalized polymer under conditions sufficient to reduce at least a portion of the graphene oxide to reduced graphene oxide. Embodiment 14 is the process of embodiment 13, wherein the reduced graphene oxide is attached to functionalized polymer through covalent bonds. Embodiment 15 is the process of any one of embodiments 13 to 14, wherein the applied photonic energy is at least 0.2 joules per centimeter squared (J/cm^"2) or 0.5 J.cm^"2 to 3.1 J.cm^"2 at room temperature and pressure. Embodiment 16 is the process of any one of embodiments 13 to 15, wherein graphene oxide attached to the functionalized polymer is obtained by: subjecting a polymer and a linker group to conditions sufficient to covalently bond the polymer with the linker group, forming a polymer/linker group material; and contacting the polymer/linker group material with graphene oxide under conditions sufficient to covalently bond the linker group to the graphene oxide, forming the graphene oxide attached to a functionalized polymer, wherein the linker group is covalently bonded to the graphene oxide and the polymer. Embodiment 17 is the process of embodiment 16, wherein the linker group comprises an oxygen atom, a sulfur atom, a nitrogen atom, or combinations thereof. Embodiment 18 is the process of embodiment 17, wherein the linker group is a thiophenol, an aminothiophenol, a diamine compounds, a maleic anhydride compound, preferably, 4- mercaptophenol. Embodiment 19 is the process of any one of embodiments 13 to 18, wherein the film is obtained by: coating at least a portion of a surface of a substrate with a solution comprising a solvent and the graphene oxide attached to the functionalized polymer; and removing the solvent to form the film on at least a portion of the surface of the substrate. Embodiment 20 is the process of embodiment 19, wherein the solution further comprises polyvinylidene fluoride (PVDF), a PVDF copolymers, polydimethylsiloxane (PDMS), polymethylmethacrylate, polytetrafluoroethylene, a polymer foam, PVC,poly(methylmethaciylate)-copoly(lH-lHperfluoroctylmethyacylate), a fluorinated parylene, or blends thereof.

[0012] The following includes definitions of various terms and phrases used throughout this specification. [0013] An "aliphatic" group is an acyclic or cyclic, saturated or unsaturated carbon group, excluding aromatic compounds. A linear aliphatic group does not include tertiary or quaternary carbons. Non-limiting examples of aliphatic group substituents include halogen, hydroxyl, alkyoxy, haloalkyl, haloalkoxy, carboxylic acid, ester, amine, amide, nitrile, acyl, thiol and thioether. A branched aliphatic group includes at least one tertiary and/or quaternary carbon. Non-limiting examples of branched aliphatic group substituents include alkyl, halogen, hydroxyl, alkyoxy, haloalkyl, haloalkoxy, carboxylic acid, ester, amine, amide, nitrile, acyl, thiol and thioether. A cyclic aliphatic group is includes at least one ring in its structure. Polycyclic aliphatic groups may include fused, e.g., decalin, and/or spiro, e.g., spiro[5.5]undecane, polycyclic groups. Non-limiting examples of cyclic aliphatic group substituents include alkyl, halogen, hydroxyl, alkyoxy, haloalkyl, haloalkoxy, carboxylic acid, ester, amine, amide, nitrile, acyl, thiol and thioether.

[0014] An "alkyl" group is linear or branched, substituted or substituted, saturated hydrocarbon. Non-limiting examples of alkyl group substituents include alkyl, halogen, hydroxyl, alkyoxy, haloalkyl, haloalkoxy, carboxylic acid, ester, amine, amide, nitrile, acyl, thiol and thioether.

[0015] An "aryl" group or an "aromatic" group is a substituted or substituted, mono- or polycyclic hydrocarbon with alternating single and double bonds within each ring structure. Non-limiting examples of aryl group substituents include alkyl, halogen, hydroxyl, alkyoxy, haloalkyl, haloalkoxy, carboxylic acid, ester, amine, amide, nitrile, acyl, thiol and thioether. [0016] A "heteroaryl" group or a "heteroaromatic" group is a mono-or polycyclic hydrocarbon with alternating single and double bonds within each ring structure, and at least one atom within at least one ring is not carbon. Non-limiting examples of heteroaryl group substituents include alkyl, halogen, hydroxyl, alkyoxy, haloalkyl, haloalkoxy, carboxylic acid, ester, amine, amide, nitrile, acyl, thiol and thioether. [0017] "Nanostructure," "nanomaterial," or "nanocomposite" each refers to an object or material in which at least one dimension of the object or material is equal to or less than 1000 nm (e.g., one dimension is 1 to 1000 nm in size or preferably 1 to 100 nm). In a particular aspect, the nanostructure includes at least two dimensions that are equal to or less than 1000 nm (e.g., a first dimension is 1 to 1000 nm in size or preferably 1 to 100 nm and a second dimension is 1 to 1000 nm in size or preferably 1 to 100 nm). In another aspect, the nanostructure includes three dimensions that are equal to or less than 100,000 nm (e.g., a first dimension is 1 to 1000 nm in size or preferably 1 to 100 nm, a second dimension is 1 to 1000 nm in size or preferably 1 to 100 nm, and a third dimension is 1 to 1000 nm in size or preferably 1 to 100 nm). The shape of the nanostructure can be of a wire, a particle (e.g., having a substantially spherical shape), a rod, a tetrapod, a hyper-branched structure, a tube, a cube, or mixtures thereof. "Parylene" is a generic term for polymers of xylene as shown by the generic

Parylenes can be substituted on the aromatic ring or the methylene group by halogen substituent (e.g., chloro-, fluoro-, etc.)

[0019] The terms "about" or "approximately" are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment, the terms are defined to be within 10%, preferably within 5%>, more preferably within 1%, and most preferably within 0.5%.

[0020] The terms "wt.%," "vol.%," or "mol.%" refers to a weight percentage of a component, a volume percentage of a component, or molar percentage of a component, respectively, based on the total weight, the total volume of material, or total moles, that includes the component. In a non-limiting example, 10 grams of component in 100 grams of the material is 10 wt.%) of component.

[0021] The term "substantially" and its variations are defined to include ranges within 10%, within 5%, within 1%, or within 0.5%.

[0022] The terms "inhibiting" or "reducing" or "preventing" or "avoiding" or any variation of these terms, when used in the claims and/or the specification includes any measurable decrease or complete inhibition to achieve a desired result.

[0023] The term "effective," as that term is used in the specification and/or claims, means adequate to accomplish a desired, expected, or intended result.

[0024] The use of the words "a" or "an" when used in conjunction with any of the terms "comprising," "including," "containing," or "having" in the claims, or the specification, may mean "one," but it is also consistent with the meaning of "one or more," "at least one," and "one or more than one."

[0025] The words "comprising" (and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "includes" and "include") or "containing" (and any form of containing, such as "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0026] The triboelectrically active films of the present invention can "comprise," "consist essentially of," or "consist of ' particular ingredients, components, compositions, etc. disclosed throughout the specification. With respect to the transitional phrase "consisting essentially of," in one non-limiting aspect, a basic and novel characteristic of the triboelectrically active films of the present invention are their abilities to convert mechanical energy into electrical energy.

[0027] Other objects, features and advantages of the present invention will become apparent from the following figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific embodiments of the invention, are given by way of illustration only and are not meant to be limiting. Additionally, it is contemplated that changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Advantages of the present invention may become apparent to those skilled in the art with the benefit of the following detailed description and upon reference to the accompanying drawings.

[0029] FIG. 1 is a schematic of the triboelectrically active film of the present invention.

[0030] FIG. 2 is a schematic of a process to prepare the triboelectrically active film of the present invention. [0031] FIG. 3 is a cross-sectional view of an electronic device that include the triboelectric-based component of the present invention. [0032] FIGS. 4A and 4B show images of a (4A) polyvinyl chloride-graphene oxide (PVC- GO) film and (4B) functionalized PVC-g-graphene oxide (f-PVC-g-GO) of the present invention.

[0033] FIGS. 5 A-C show the Raman spectra of the (5 A) PVC, (5B) f-PVC, and (5C) f- PVC-g-GO materials.

[0034] FIGS. 6A-6C show Fourier Transform infrared (FTIR) spectra of (6A) PVC, (6B) f-PVC, (6C) f-PVC-g-GO.

[0035] FIGS. 7A-7C show ¾ MR spectra of (7 A) PVC, (7B) f-PVC, (7C) f-PVC-g-GO.

[0036] FIGS. 8A-E are images of the f-PVC-g-GO samples at different photonic energy strength exposure.

[0037] FIGS. 9A-E show FTIR spectra of reduced f-PVC-g-GO film after different photonic energy treatments.

[0038] FIG. 10 is a cross-sectional view of an electronic device that include the triboelectric-based component positioned on an indium tin oxide (ITO) electrode. [0039] FIGS. 11A-11E show the triboelectric energy output voltage from the prepared triboelectric devices containing PVC-GO; (11 A) PVC-GO treated at at 0 Tern^"2, (11B) PVC- GO treated at 0.827 J.cm^"2, (11C) PVC-GO treated at 1.627 J.cm^"2, (1 ID) PVC-GO treated at 3.0341 J.cm^"2, and (HE) PVC-GO treated at 3.251 J.cm^"2.

[0040] FIGS. 12A-12F show the triboelectric energy output voltage from prepared triboelectric devices containing (12A) PVC, (12B) f-PVC-g-GO of treated at 0 J.cm^"2, (12C) f- PVC-g-GO of treated at 0.675 J.cm^"2, (12D) f-PVC-g-GO of treated at 1.655 J.cm^"2, (12E) PVC- f-PVC-g-GO of treated at 2.291J.cm^"2, and (12F) f-PVC-g-GO of treated at 3.0251 J.cm^"

2

[0041] FIG. 13 is a graphical depiction of the triboelectric response versus different photonic energy treatments of the triboelectric devices containing PVC-GO.

[0042] FIG. 14 is a graphical depiction of the triboelectric response versus different photonic energy treatment the triboelectric devices containing PVC-g-GO containing films.

[0043] FIG. 15 shows data plotted with comparative materials PVC, PVDF-TrFE, non- reduced PCV-g-GO, physically mixed PVC and GO, and the triboelectric component of the present invention. [0044] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings. The drawings may not be to scale.

DETAILED DESCRIPTION OF THE INVENTION [0045] A discovery has been made that provides a solution to at least some of the above- mentioned problems associated with conventional triboelectrically active films. The solution is premised covalent attachment of a functionalized polymer to graphene oxide to form a nanomaterial (e.g., a nanocomposite). Such an attachment can homogeneously disperse graphene in a polymer matrix of the functionalized polymer and provide for efficient graphene/polymer interactions, leading to improved triboelectric properties such as increased output voltage. Furthermore, the process to manufacture the triboelectrically active films of the present invention provides an elegant and efficient way to produce the triboelectrically active films while limiting any adverse effect on the polymer (e.g., loss of mechanical or physical properties). [0046] These and other non-limiting aspects of the present invention are discussed in further detail in the following sections with reference to the FIGS.

A. Triboelectrically Active Film

[0047] The triboelectrically active film of the present invention can include a graphene material attached to a functionalized polymer. FIG. 1 depicts a schematic of the triboelectrically active material of the present invention. Triboelectrically active material 100 can include graphene material 102 attached to functionalized polymer matrix 104. Functionalized polymer matrix 104 includes linker 106, which attaches to the graphene material. In a preferred embodiment, linker 106 can be covalently attached to the polymer matrix and the graphene material. Such an attachment can provide homogeneous dispersement of the graphene in the polymer matrix. Portions or all of the graphene material 102 can be reduced. In certain aspects, graphene material 102 can be a mixture of reduced graphene oxide (r-GO) attached to the polymer and unreduced graphene oxide attached to the polymer. In some embodiments, the graphene oxide is partially reduced, resulting in the functionalized polymer attached to a mixture of graphene oxide and reduced graphene oxide. In other embodiments, all of the graphene oxide is reduced, resulting in the functionalized polymer attached to reduced graphene oxide. [0048] Polymer matrix 104 can be a thermoplastic polymer matrix. The thermoplastic polymer can be functionalized. Thermoplastic polymeric matrices have the ability to become pliable or moldable above a specific temperature and solidify below the temperature. The polymeric matrix of the composites can include thermoplastic or thermoset polymers, co- polymers thereof, and blends thereof that are discussed throughout the present application. Non-limiting examples of thermoplastic polymers include polyethylene terephthalate (PET), a polycarbonate (PC) family of polymers, polybutylene terephthalate (PBT), poly(l,4- cyclohexylidene cyclohexane-l,4-dicarboxylate) (PCCD), glycol modified polycyclohexyl terephthalate (PCTG), poly(phenylene oxide) (PPO), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), polymethylmethacrylate (PMMA), polyethyleneimine or polyetherimide (PEI) and their derivatives, thermoplastic elastomer (TPE), terephthalic acid (TPA) elastomers, poly(cyclohexanedimethylene terephthalate) (PCT), polyethylene naphthalate (PEN), polyamide (PA), polystyrene sulfonate (PSS), sulfonates of polysulfones, polyether ether ketone (PEEK), polyether ketone ketone (PEKK), acrylonitrile butyldiene styrene (ABS), polyphenylene sulfide (PPS), polyvinyl dichloride (PVDC), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), co-polymers thereof, or blends thereof. In a preferred embodiment, the thermoplastic polymer matrix is PVC, PVDC, PVF, PVDF, PCTFE, PTFE, or blends thereof.

[0049] Polymer matrix 104 can be a thermoplastic polymer matrix that includes linker 106. Linker 106 can be represented by the formula XRY, where R is an alkyl or aromatic moiety, and X and Y are heteroatoms, where X and Y can be the same or different. Non-limiting examples of a heteroatoms include a nitrogen (N) atom, a sulfur (S) atom, and an oxygen (O) atom. R can be an aliphatic moiety, an aromatic moiety, or a heteroatom moiety. In some embodiments XRY is a maleic anhydride compound or derived from maleic anhydride. A non- limiting example of XRY, when R is an aromatic moiety is shown as structure (I):

where Ri, R2, R3 and R₄ can each independently be hydrogen atom (H), a halogen, an alkyl group, a substituted alkyl group, a heteroalkyl group, a substituted heteroalkyl group, a cycloalkyl group, a substituted cycloalkyl group, a heterocycloalkyl group, a substituted heterocycloalkyl group, an aryl group, a substituted aryl group, a benzyl group, a substituted benzyl group, a heteroaryl group, a substituted heteroaryl group, an alkoxy group, and alkoxyalkyl group, an alkoxyalkoxy group, and alkoxyalkoxyalkyl group, an alkoxycarbonyl group, an amino group, or a hydroxyl group. Non-limiting examples of halogens include chloride, bromide, fluoride and iodide. In a certain instance, Ri, R2, R3, R4, or combinations thereof can be fluoride (F), -CF3, or combinations thereof. In some instances, Ri, R2, R3 and R₄ are H, Y is a sulfur atom and X is an oxygen atom (Structure (II)) or a NR5, where R5 is H or an aliphatic group or a substituted aliphatic group (Structure (III)). In such cases, X can be bonded to the graphene material and Y is bonded to the polymer.

Structure IV represents an aliphatic R moiety of linker 106

^X (^CH2)n ^Y (jy) where n is 2 to 6 and X and Y are defined as above for the aromatic linker. [0050] The triboelectrically active film can also include other ingredients. By way of example, polymers can be added to form a polymeric blend with the graphene material attached to the functionalize polymer. Non-limiting examples of polymers that can be blended with the graphene material attached to the functionalize polymer include polyvinylidene fluoride (PVDF), a PVDF copolymers, polydimethylsiloxane (PDMS), polymethylmethacrylate, polytetrafluoroethylene, a polymer foam, poly(methylmethacrylate)-copoly(lH-lH- perfluoroctylmethyacylate), a fluorinated parylene, or blends thereof.

B. Process of to Produce the Triboelectric-Based Component

[0051] The triboelectrically active film of the present invention can be made by attaching the functionalized polymer to graphene oxide, casting a solution of the graphene material attached to the functionalized polymer on at least a portion of a surface of an electrode to form a film. Photonic energy can be applied to the film such that some or all of the graphene oxide is reduced. Applying photonic energy provides an advantage over chemical or thermal reduction as the polymer properties are substantially unchanged, and the number of processing steps are reduced. FIG. 2 is a schematic of process 200 for the production of the triboelectric- based component of the present invention. In step 1 of process 200, functionalized polymer attached to a graphene material (f-P— GM) 202 can be obtained. In some embodiments, f-P— GM 202 can be produced using organic synthetic esterification methodology. By way of example, a functionalized polymer and graphene oxide can be suspended in a solvent (e.g., cyclohexanone). Graphene oxide can be prepared using a modified Hummer's method as described in a non-limiting method of the Examples section, or purchased from a commercial source. The suspension can be agitated under inert atmosphere (e.g., argon atmosphere) at 60 °C to 85 °C, 65 °C to 80 °C or about 70 °C for a desired period of time (e.g., 60 to 80 hours or 70 to 75 hours). A solution of coupling agent (e.g., Ν,Ν-dicyclohexylcarbodiimide (DCC)) and catalyst (e.g., 4-(dimethylamino) pyridine (DMAP)) in a solvent (e.g., cyclohexanone) can be added to the suspension and the resulting suspension can be agitated at 30 °C to 50 °C, 35 °C to 45 °C, or about 40 °C for a desired amount time ((e.g., 60 to 80 hours or 70 to 75 hours) to produce the graphene oxide attached to the functionalized polymer. Precipitation of the f-P— GM can be realized by addition of an anti-solvent (e.g., methanol) under vigorous agitation. The resulting precipitate can be isolated (e.g., by filtration, centrifugation, etc.), washed with anti-solvent, and dried (e.g., at 50 °C under vacuum for about 30 hours).

[0052] In some embodiments, the functionalized polymer can be functionalized PVC. In a preferred embodiment, PVC can be functionalized with 4-sulfanylphenol. By way of example, 4-hydroxythiophenol can be added to a solution of PVC, solvent (e.g., cyclohexanone), base (e.g., K2CO3). The resulting mixture can be heated at 35 to 45 °C or about 40 °C under an inert atmosphere (e.g., argon) until the reaction is deemed complete (e.g., 70 to 75 hours or about 72 hours). The resultant crude functionalized PVC can be precipitated in methanol-water mixtures (3 : 1) under vigorous agitation. The crude functionalized PVC can be purified by redispersing it into an organic solvent (e.g., THF) and adding a methanol-water system. Purified functionalized PVC (f-PVC) can be isolated (e.g., filtration, centrifugation, etc.), dried (e.g., under vacuum at 40 °C).

[0053] In step 2 of method 200, the f-P— GM 202 can be dissolved in a solvent (e.g., dimethylformamide, (DMF)) and then deposited on electrode 204 by spray coating, ultra sonic spray coating, roll-to-roll coating, ink-jet printing, screen printing, drop casting, spin coating, dip coating, Mayer rod coating, gravure coating, slot die coating, doctor blade coating, extrusion coating, flexography, gravure, offset, rotary screen, flat screen, ink-jet, roll-to-roll photolithography, or laser ablation. The solvent can be removed by heating, evaporation, or under vacuum at a suitable temperature. For example, the deposited solution was heated to 50 °C to 70 °C, or 55 °C to 65 °C, or about 60 °C at 0.001 to 0.005 MPa, or 0.003 to 0.0045 or about 0.004 MPa. Electrode 204 can be made of or include aluminum, copper, silver, indium tin oxide (ITO), tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, gallium- doped zinc oxide, PEDOT:PSS, silver nanowires/nanorods, copper nanowires/nanorods, or another conductive material or alloy. In some embodiments, a second polymer is added to the solution to produce a polymer matrix that includes a blend of polymers. Non-limiting examples of additional polymers can include polyvinylidene fluoride (PVDF), a PVDF copolymers, polydimethylsiloxane (PDMS), polymethylmethacrylate, polytetrafluoroethylene, a polymer foam, poly(methylmethacrylate)-copoly(lH-lH-perfluoroctylmethyacylate), a fluorinated parylene, or blends thereof. In some instances, the film thickness is 0.1 nm to 50000 nm, 1000 nm to 20000 nm, or greater than, equal to, or between any two of 0.1 nm, 10 nm, 100 nm, 1000 nm, 5000 nm, 10000 nm, 12000 nm, 13000 nm, 14000 nm, 15000 nm, 20000 nm, 25000 nm, 30000 nm, 35000 nm, 40000 nm, 45000 nm, 50000 nm, 55000 nm, 60000 nm, 65000 nm, and 70000 nm. The film thickness can be varied depending on the application. The deposition process can be repeated to form a film having a desired thickness. For example, one or more layers of functionalized polymer-graphene oxide film 206 can be can be used. As shown, functionalized polymer-graphene oxide film 206 covers the top surface of electrode 204. In some embodiments, the film covers a portion of the substrate. By way of example, functionalized polymer-graphene oxide film 206 covers from a portion (e.g., 0.1% to 100% or any value there between) of the substrate surface. Configurations for functionalized polymer- graphene oxide film 206 that make up the triboelectric-based component can take on one of many forms. The resulting film can be annealed at 45 °C to 100 °C or greater than, equal to, or between any two of 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, 95 °C, and 100 °C. In a preferred embodiment, the film is a functionalized PVC-graphene oxide film and can be annealed at a temperature of 55 °C to 65 °C or about 60 °C. In some embodiments, annealing of functionalized polymer-graphene oxide film 206 is not necessary.

[0054] In step 3 of method 200, functionalized polymer-graphene oxide film 206 can be subjected to photonic energy. Photonic energy can be supplied from photonic energy source 208. By way of example, a photonic energy source can be obtained from Novacentrix (U.S. A). The amount of energy applied can be at least 0.2 joules per centimeter squared (J/cm^"2) or 0.5 J/cm^"2 to 3.1 J/cm^"2, or greater than, equal to, or between any two of 0.2 J/cm^"2, 0.3 J/cm^"2, 0.4 J/cm^"2, 0.5 J/cm^"2, 0.6 J/cm^"2, 0.72 J/cm^"2, 0.8 J/cm^"2, 0.9 J/cm^"2, 1.0 J/cm^"2, 1.1 J/cm^"2, 1.2 J/cm^{" 2}, 1.3 J/cm^"2, 1.4 J/cm^"2, 1.5 J/cm^"2, 1.6 J/cm^"2, 1.7 J/cm^"2, 1.8 J/cm^"2, 1.9 J/cm^"2, 2.0 J/cm^"2, 2.1 J/cm^"2, 2.2 J/cm^"2, 2.3 J/cm^"2, 2.4 J/cm^"2, 2.5 J/cm^"2, 2.6 J/cm^"2, 2.7 J/cm^"2, 2.8 J/cm^"2, 2.9 J/cm^{" 2}, 3.0 J/cm^"2, and 3.1 J/cm^"2. Treatment of the f-P— GM film with photonic energy can reduce a portion or substantially all of the free oxygen in the graphene (e.g., the graphene oxide) of the f-P— GM film, resulting in functionalized polymer matrix attached to a graphene material 210, which includes reduced graphene oxide. This process can be used to form a triboelectric- based component 212 of the present invention.

C. Applications of the Triboelectric-Based Component [0055] The triboelectrically-based component 212 can be included in an electronic device. In the electronic device, the triboelectrically-based component 212 can be coupled to an integrated circuit and configured to read-out a user input. The electronic device can be an energy harvester, a sensor, a mobile device, a wearable device, a flexible device, a displays device, a thin film transistor (TFT) an actuator, a piezoelectric device, a logic device, or any combination thereof. In some embodiments, the article of manufacture is a virtual reality device, an augmented reality device, or a fixture that requires flexibility. Non-limiting examples of flexible devices include adjustable mounted wireless headset and ear buds, a communication helmet with curvatures, a medical patch, a flexible identification card, a flexible sporting good, a packaging material, etc. [0056] FIG. 3 is a cross-sectional view of an electronic device that include the triboelectric- based component of the present invention. Electronic device 300 can be formed or made specific for an intended use, amount of force anticipated, and/or manner of application of force. Electronic device 300 can include triboelectric-based component 212, substrate 302 and integrated circuit 304. Substrate 302 can be one of PET, PEN, PC, PMMA, polyimide, parylene-C, other thermoplastic materials, or other flexible or inflexible substrate material (e.g., glass). Electrode 204 of the triboelectric-based component 212 can couple to logic circuitry 304. Logic circuitry 304 can be an application processor or an interface to an application processor. In some device configurations, a resistor 306 can be coupled to the electrode to convey an electric signal from the triboelectric film 210 to other circuitry. In some device configurations, resistor 306 can be a thin film resistor. While a simple electronic device is shown, other devices that include piezoelectric elements, haptic feedback actuators, or the like, or combinations thereof, are also envisioned as being part of the present invention. EXAMPLES

[0057] The present invention will be described in greater detail by way of specific examples. The following examples are offered for illustrative purposes only, and are not intended to limit the invention in any manner. Those of skill in the art will readily recognize a variety of noncritical parameters which can be changed or modified to yield essentially the same results.

Example 1

(Preparation of Graphene Oxide)

[0058] Graphene oxide was prepared using a modified Hummers method Hummers' method (Hummers et ah, J. Am. Chem. Soc, 1958, 80, 1339-1339). Pre-oxidized graphite powder (about 3 g) was added to a mixture of concentrated sulfuric acid (H2SO4, about 150 mL) and potassium permanganate (KMn0₄, about 18 g) under continuous stirring at room temperature (about 20 to 30 °C) for 48 hours. Sodium nitrate (NaNCb about 3 g) was added to the solution, and the solution was stirred at about 50 °C for 6 hours. Distilled water was added to the solution and stirred for about 4 hours. Hydrogen peroxide (H2O2, 60 mL of 30%) was added to the solution. The resulting graphite oxide was exfoliated using hydrothermal conditions at 180 °C for 6 hours to produce graphene oxide.

Example 2

(Preparation of Functionalized PVC)

[0059] PVC was functionalized with 4-mercaptophenol as shown in the reaction scheme below.

PVC (1.5 g, 24.0 mmol, based on monomeric unit) was dissolved in cyclohexanone (140 mL), and K2CO3 (3.30 g, 23.8 mmol) and 4-mercaptophenol (3.0 g. 23.8 mmol) were added to the polymer PVC solution. The mixture was stirred and heated at 40 °C under argon. After 72 h reaction time, resultant mixture was precipitated in methanol -water mixtures (3 : 1) and stirred vigorously for 3 hours to fully precipitate the crude functionalized PVC. Crude functionalized PVC was purified by dispersing the crude product into THF and precipitating the functionalized PVC using the methanol-water mixture (3 : 1). The resultant hydroxy functionalized polymer (f-PVC) was dried under vacuum at 40 °C and characterized by FTIR, ¾ NMR and Raman spectroscopy.

Example 3

(Preparation of f-PVC-Graphene oxide/ Material)

[0060] The graphene oxide from Example 1 was grafted on the f-PVC of Example 2 to form a f-PVC-graphene oxide (GO) material as shown in the reaction scheme below.

GO (40 mg) and f-PVC (0.5 g) were suspended in cyclohexanone (25 mL). The suspension was gently stirred and maintained at 70 °C under argon for 72 hours. Then, a solution of N,N- dicyclohexylcarbodiimide (DCC) (1.84 g, 9 mmol), 4-(dimethylamino) pyridine (DMAP) (0.136 g, 1.1 mmol) in cyclohexanone (20 mL) was added, and the resulting mixture was stirred at 40 °C for another 72 hours. Coagulation of the polymer nanocomposite was accomplished by adding the suspension into a large excess of methanol under vigorous stirring. The solid nanocomposite (f-PVC-g-GO) was filtered, washed with methanol and dried at 50 °C under vacuum. The non-reacted GO was removed by dissolving the solid in THF, and centrifuged at a high speed (16000 rpm) for 30 min. The supernatant solution coagulated with methanol and stirred for 4 hours to precipitate completely. The resultant f-PVC-g-GO was dried under vacuum at 50 °C for 30 hours.

Example 4

(Preparation of f-PVC-Graphene Oxide and PVC-Mixed Graphene Oxide films)

[0061] Purified and dried f-PVC-g-GO (600 mg, Example 3) was dissolved in dimethylformamide (DMF, 5 mL) and the resulting mixture was used for preparation of thin film through automatic film coater technique and the prepared thin film. The film was annealed at 60 °C for 2 hours and thickness was measured by screw gauge that was very uniform in the range of 15 μπι. PVC physically mixed with graphene oxide (PVC-GO) was made into a film using the same methodology. FIGS. 4A and 4B are images of a PVC-GO (4A) before and f- PVC-g-GO films (4B).

Example 5

(Characterization of f-PVC-g-GO Film) [0062] Samples from Example 4 were characterized by FTIR, ¾ MR and Raman spectroscopy to give a preliminary examination on the existence of GO and PVC interaction. Further reduction of graphene oxide and its effect on triboelectric energy was studied. The working of the f-PVC-g-GO based triboelectric was performed by applying a mechanical force on the nanogenerator, output voltage recorded by Keithley 6514 electrometer system. [0063] Raman Spectroscopy. Raman spectroscopy (DXR Raman microscope configured with 532 nm laser (Thermo Fisher Scientific, U. S.A.)) was used to monitor the structural change of graphene-based materials of f-PVC-g-GO undergoing reduction by photonic energy. FIGS. 5A-C display the Raman spectra of the (5 A) PVC, (5B) f-PVC, and (5C) f-PVC-g-GO materials (e.g., nanocomposite). In the FIG. 5A spectra, all bands of PVC were recognized at 1000, 1 100, 1490, 2210, 2605, and 2995 cm^-1. In the FIG. 5B spectra, the band at 1 160 cm^-1 corresponding to the modified polymer was observed. This band was assigned to the S-aryl stretching for the aromatic modifier (4-sulfanylphenol). In the FIG. 5C spectra, intense distinguishable peaks at 1328 and 1598 cm^"1 corresponding to D and G bands, respectively, of graphene. The D band is ascribed to the lattice defect induced phonon mode and G band refers to the C-C bond expansion or contraction in the hexagonal carbon plane. It is known that the 2D band is valuable to differentiate the monolayer from multi-layer sheets in graphene based materials. Without wishing to be bound by theory, it is believed that the 2D band intensity in f-PVC-g-GO suggests the formation of exfoliated GO sheets from the dense multilayer GO sheets. Besides the much higher Raman efficiency of the GO signals, weak bands of the PVC were observed at 615-630, 699, and 1429 cm^"1. The Raman spectrum of f-PVC shows the bands of the polymer on the top of a broad fluorescent band originated in the aromatic moieties. This fluorescent band was absent in the spectrum of f-PVC-g-GO due to quenching of fluorescence by the carbon nanostructures, which is an indirect evidence of the effective attachment of GO on the PVC.

[0064] Fourier Transmission Infrared (FTIR). FTIR spectrum of the f-PVC-g-GO was obtained using a Thermo Fisher Scientific Nicolet™ 6700 spectrometer. FIGS. 6A-6C depict FTIR spectra of (6 A) PVC, (6B) f-PVC, (6C) f-PVC-g-GO. Absorption bands characteristic of the f-PVC (signals at 1497, 1587, and 1602 cm^"1 corresponding to the aromatic C=C vibration modes, and a band around 3400 cm^"1 due to hydroxyl function) overlapped with new bands (FIG. 6B) were observed. The effective linkage between the GO and the f-PVC was evident from the FTIR spectrum, which showed a band at 1658 and 1737 cm^"1 corresponding to C=0 stretching of carboxylic acid and ester groups, respectively (FIG. 6C). Detection of the ester group (-COOAr) peak clearly shows the effective covalent interaction between GO and f-PVC.

[0065] ¾ NMR. ¾ MR spectra of the Example 4 samples in deuterated THF were obtained using a Bruker 400 mHz spectrometer (Bruker Corporation, U.S.A.). FIGS. 7A-7C show ¾ NMR spectra of (7 A) PVC, (7B) f-PVC, (7C) f-PVC-g-GO. The ¾ NMR spectrum of the f-PVC-g-GO (FIG. 7C) was quite different from the corresponding f-PVC (FIG. 7B), especially in the zone of the aromatic (7.5-6.9 ppm) and hydroxyl protons (7.9 ppm). First, the intensity of the hydroxyl proton peak remarkably decreased after the esterification reaction. On the other hand, two new signals at 7.21 and 7.62 ppm appear. These signals correspond to aromatic protons in a different environment and can be due to the influence of the carbonyl of the ester group on the protons of the benzene ring. As was explained for PVC grafted GO, the discrimination of both types of protons, i.e. protons of the f-PVC-g-GO samples and protons of them PVC units, allowed the percentage of GO in the sample to be estimated. On the basis of the integration of the signals the amount of GO in f-PVC-g-GO was estimated to be about 1.5 wt. % units based on total composition.

Example 6

(Preparation of a Triboelectrically Active Film of the Present Invention-Coating) [0066] The f-PVC-g-GO and PVC-GO films were formed by doctor blading in the range of thickness 15 μπι on an ITO coated glass substrate and then reduced using photonic energy. Pulse Forge 1300 (Novacentrix (U.S. A)) was used for photonic energy source and applied energy was controlled by controlling the voltage and pulse length. FIGS. 8A-E are images of the f-PVC-g-GO samples at different photonic energy strength exposure. f-PVC-g-GO sample without any photonic treatment is shown in FIG. 8A. In FIG. 8B, 300V and 800 pulse length were used, which yielded an amount of applied energy of 0.675 J/cm^"2. There was no defect observed at this energy, except the color of the film darkened. Applied photonic energy was increased 1.655 J/cm^"2 and 2.291 J/cm^"2 by increasing the applied voltage to 400 V and 500 V, respectively with pulse length 800 (FIGS. 8C and 8D). No damage or wrinkle up was observed. Application of photonic energy at 3.025 J/cm^"2, resulted darker films and surface damage was observed (FIG. 8E). All samples were analyzed, to study the effect of reduction on the triboelectric properties after exposed various strength of photonic energy.

Example 7

(FTIR Characterization of Reduction Using Photonic Energy. ) [0067] Confirmation that reduction of GO in Example 6 samples occurred was performed using FTIR by analysis of the carboxylic peak at 1653 cm^"1 of portions of the film removed from the ITO surface. FIGS. 9A-E show FTIR spectra of reduced f-PVC-g-GO film after different photonic energy treatments. The decrease in the peak intensity of the carboxylic group was attributed to the reduction of GO in the f-PVC-g-GO film. Increasing of the power of photonic energy correspondingly reduction effect was recognized by carboxyl peak intensity from FIGS. 9A-E. Noticeably, photonic curing does not show any adverse impact on the polymer as there is no new peak recognized in the FTIR spectrum. It shows clearly, photonic energy effectively reduced the GO without impacting the nanocomposites properties.

Example 8

(Fabrication of a Triboelectric Material)

[0068] A one-square inch indium tin oxide (ITO) coated glass substrate was used as an electrode and a triboelectrically active film containing reduced f-PVC-g-GO (prepared as described for Examples 1-4), or a PVC-GO film was layered as triboelectric active layer on top of the ITO and was connected through the ITO layer to a conventional resistor of 500 ΜΩ as schematically depicted as shown in FIG. 10. The graphene oxide in each sample was reduced using photonic energy at various levels listed in Tables 1 and 2 below. All the films in the device had a similar thickness of about 15 μπι.

Example 9

(Characterization of Comparative and Inventive Triboelectric Component)

[0069] The triboelectric components made from reduced f-PVC-g-GO film and reduced PVC-GO film were characterized for triboelectric voltage output. A touch force was applied on the film, which was connected to electrometer to record the output voltage. The touch sensor was characterized using a Keithley 6514 electrometer system (Tektronix, U.S.A.), which was able to measure output voltage generated by the sensor, which is the same as voltage drop across the load. In the device, an external load of 500 ΜΩ was used. Lab View software (National Instruments, U.S.A.) was programed to record all the data measured by the electrometer, and used to plot the output voltage.

[0070] Table 1 lists the data of applied photonic energy, maximum positive voltage (+V), maximum negative voltage (-V), average of +V and -V; and triboelectric total output V for the triboelectric devices containing PVC, untreated PVC-GO, and reduced PVC-GO films. Table 2 lists the data of applied photonic energy, maximum +V, maximum -V, average of +V and - V; and triboelectric total output V and triboelectric total output voltage for the triboelectric devices containing PVC, untreated f-PVC-g-GO, and reduced f-PVC-g-GO films. The PVC triboelectric device had a total triboelectric voltage of 0.867 V, the untreated PVC-GO triboelectric device had a maximum total triboelectric voltage of 2.311, and the untreated f- PVC-g-GO triboelectric device had a triboelectric voltage of 2.086 V. Without wishing to be bound by theory, it is believed that the GO enhanced the electronegativity of the entire triboelectric active layer as well as having surface charge carrier mobility. The untreated f- PVC-g-GO triboelectric device had higher total voltages than the treated PVC-GO. Table 1

Table 2

[0071] FIGS. 11A-E (PVC-GO), 12A (PV), and 12B-F (f-PVC-g-GO material of the present invention) show the triboelectric energy output voltage from the prepared triboelectric devices. From the data in FIGS. 11 and 12, it was determined that the amount of photonic energy used to prepare the triboelectrically active film impacted the triboelectric output voltage. It was also determined that covalently bonding of the graphene to the PVC via a linker group {i.e., f-PVC-g-GO) increased the triboelectric output voltage as compared to devices made with PVC physically mixed with graphene oxide {i.e., PVC-GO). Noticeably, the materials containing f-PVC-g-GO films subjected to higher photonic energy exposure {e.g., greater than 0.827 J.cm^"2), showed more consistency in output voltage as compared to those at low power treatment {e.g., less than or equal to 0.827 J.cm^"2). Overall, the f-PVC-g-GO containing films of the present invention showed almost two times higher output voltage as compared to pristine PVC {see, FIG. 12). FIGS. 13 (PVC-GO) and 14 (f-PVC-g-GO of the present invention) are graphical depictions of the triboelectric response versus different photonic energy treatment the triboelectric devices containing PVC-GO and f-PVC-g-GO films, respectively. From the data, it was observed that photonic energy exposure up to 1 J/cm² increased triboelectric energy, but after that the triboelectric energy start dropping. Example 10

(Comparative Experiments)

[0072] Comparative films of PVC and PVDF-TrFe were made by dissolving a 12 wt. % formulation of the polymer (PVC or PVDF-TrFE), in DMF and then spin coating at 1000 rpm to yield 10 μπι thick film. The films were fabricated into triboelectric devices as described in Example 9. FIG. 15 shows data plotted with comparative materials PVC, PVDF-TrFE, PCV- g-GO with no reduction, physically mixed PVC and GO, and the triboelectric component of the present invention. PVC and PVDF-TrFE had touch output voltages of 0.827 V and 1.98 V, respectively. A triboelectric output voltage increment was observed in both PCV-g-GO with no reduction, physically mixed PVC and GO samples. The triboelectric component of the present invention has the highest touch output voltage of 4.0 V.

[0073] In summary, the triboelectric components of the present invention demonstrated an increase in the triboelectric properties through GO covalently grafted on to PVC and in situ reduction of the GO by applying photonic energy. Importantly, when physically GO mixed PVC nanocomposite and triboelectric film of the present invention was exposed the similar photonic power, a higher triboelectric output was recorded in the triboelectric film of the present invention (covalently attached). Without wishing to be bound by theory, it is believed that covalently attaching GO to the polymer through a linking group increases the electronegativity in the resulting material {e.g., nanocomposites). Furthermore, when triboelectric film of the present invention was exposed to higher photonic power, reduction the GO on the surface was achieved without influencing the properties of bulk polymer.

[0074] As demonstrated in the Examples, the triboelectrically active film of the present invention provides an advantage over conventional triboelectric active materials PVDF-TrFE, which are saturated on touch sensor output voltage. The preparation of GO covalently grafted PVC and further reduction of the GO in the nanocomposite via photonic energy can be seamless. Furthermore, the in situ reduction of GO in the triboelectric active materials provides an economical advantage over chemical or thermal reduction methods as well as minimal to no change in the polymer properties.

[0075] Although embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the above disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein can be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

1. A triboelectric-based component comprising a triboelectrically active film positioned on at least a portion of a surface of an electrode, the triboelectrically active film comprising a graphene material attached to a functionalized polymer.

2. The triboelectric-based component of claim 1, wherein the graphene material is covalently bonded to the functionalized polymer.

3. The triboelectric-based component of claim 2, wherein the functionalized polymer comprises a linker group, and wherein the linker group is covalently bonded to the graphene material.

4. The triboelectric-based component claim 3, wherein the linker group comprises a sulfur atom, a nitrogen atom, an oxygen atom, or combinations thereof.

5. The triboelectric-based component of claim 4, wherein the linker group comprises sulfur and oxygen atoms, and wherein the sulfur atom covalently bonds to the polymer and the oxygen atom covalently bonds to the graphene material.

6. The triboelectric-based component of claim 1, wherein the functionalized polymer comprises a thermoplastic material.

7. The triboelectric-based component of claim 6, wherein the thermoplastic material is polyvinyl chloride (PVC), polyvinyl dichloride (PVDC), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polycholorotrifluoro ethylene (PCTFE), polytetrafluoroethylene (PTFE).

8. The triboelectric-based component of claim 1, wherein the graphene material comprises reduced graphene oxide.

9. The triboelectric-based component of claim 8, wherein the reduced graphene oxide is derived from photonic energy reduction of graphene oxide.

10. The triboelectric-based component of claim 1, wherein the triboelectric film is a blend of the graphene material and at least one of polyvinylidene fluoride (PVDF), a PVDF copolymers, polydimethylsiloxane (PDMS), PVC, polymethylmethacrylate, polytetrafluoroethylene, a polymer foam, or poly(methylmethacrylate)-copoly(lH-lH- perfluoroctylmethyacylate), a fluorinated parylene.

11. An electronic device comprising a triboelectric-based component of claim 1 and an integrated circuit coupled to the triboelectric-based component and configured to readout a user input to the triboelectric-based component.

12. The electronic device of claim 11, wherein the electronic device is an energy harvester, a sensor, a mobile device, a wearable device, a flexible device, a displays device, a thin film transistor (TFT), or any combination thereof.

13. A process to produce a triboelectrically active material, the process comprising applying photonic energy to a film comprising graphene oxide attached to a functionalized polymer under conditions sufficient to reduce at least a portion of the graphene oxide to reduced graphene oxide.

14. The process of claim 13, wherein the reduced graphene oxide is attached to functionalized polymer through covalent bonds.

15. The process of claim 13, wherein the applied photonic energy is at least 0.2 joules per centimeter squared (J/cm^"2) or 0.5 J. cm^"2 to 3.1 J. cm^"2 at room temperature and pressure.

16. The process of claim 13, wherein graphene oxide attached to the functionalized polymer is obtained by:

subjecting a polymer and a linker group to conditions sufficient to covalently bond the polymer with the linker group, forming a polymer/linker group material; and

contacting the polymer/linker group material with graphene oxide under conditions sufficient to covalently bond the linker group to the graphene oxide, forming the graphene oxide attached to a functionalized polymer, wherein the linker group is covalently bonded to the graphene oxide and the polymer.

17. The process of claim 16, wherein the linker group comprises an oxygen atom, a sulfur atom, a nitrogen atom, or combinations thereof.

18. The process of claim 17, wherein the linker group is a thiophenol, an aminothiophenol, a diamine compounds, or a maleic anhydride compound.

19. The process of claim 13, wherein the film is obtained by:

coating at least a portion of a surface of a substrate with a solution comprising a solvent and the graphene oxide attached to the functionalized polymer; and removing the solvent to form the film on at least a portion of the surface of the substrate.

20. The process of claim 19, wherein the solution further comprises polyvinylidene fluoride (PVDF), a PVDF copolymers, polydimethylsiloxane (PDMS), polymethylmethacrylate, polytetrafluoroethylene, a polymer foam, PVC,poly(methylmethacrylate)-copoly(lH-lHperfluoroctylmethyacylate), a fluorinated parylene, or blends thereof.