Method for peeling and / or functionalizing layered materials, and related apparatus.

Abstract

A method for exfoliating and / or functionalizing a layered object, and related apparatus, comprising the steps of: immersing at least one portion of a first electrode in a liquid containing the layered object to be exfoliated and / or functionalized; disposing a second electrode outside the liquid, with at least one portion of the second electrode facing the surface of the liquid; and applying a pulse voltage difference between the first electrode and the second electrode to generate a plasma between the surface of the liquid and the at least one portion of the second electrode facing the surface of the liquid.

Description

[Technical Field]

[0001] The present invention relates to the field of producing nanofillers intended to be incorporated into composite materials, particularly polymer composite materials. The nanofillers are, for example, lamellar materials such as graphene or graphene materials. The present invention also relates to methods for processing the nanofillers, particularly methods for exfoliating and / or functionalizing the nanofillers. [Background technology]

[0002] Conventionally, wet functionalization of layered materials by chemical acid and / or oxidation treatment is known. This treatment requires strict operating conditions and necessitates the use of hazardous chemical compounds that have a significant impact on the environment.

[0003] The functionalization of layered materials by plasma treatment has also been known. This plasma treatment process involves the interaction between the plasma and the surface of the material being treated, which results in a reaction between the plasma reactants and the material being treated.

[0004] Conventionally, ultrasonic treatment is known as a technique for delaminating layered materials. However, this method is limited in terms of efficiency because it requires multiple steps to obtain the desired result.

[0005] Furthermore, a conventional technique is micromechanical delamination, in which a sheet of graphene is mechanically separated by the separation of one sheet or a group of sheets of graphite or graphene material. This approach is not feasible on an industrial scale. [Overview of the project] [Problems that the invention aims to solve]

[0006] The objective of the present invention is, in particular, — To avoid using chemical compounds that are harmful or have a significant impact on the environment, and / or — To obtain a multilayered material, and / or, — Obtaining several layers of material from a macroscopic layered material, and / or, — Functionalizing layered materials, and / or, — To obtain a layered material, and / or, — Obtaining a layered material in one step, and / or functionalizing a layered material in one step, and / or obtaining a functionalized layered material in one step, and / or — The resulting layered material and / or the resulting functionalized layered material shall have virtually no structural defects, and / or — The advantages are that it is not very energy-intensive, but is simple and easy to implement, and / or that the resulting layered material and / or the resulting functionalized layered material can be controlled. [Means for solving the problem]

[0007] For this purpose, A method for peeling and / or functionalizing a layered material, - A step of immersing at least one portion of a first electrode in a liquid containing the layered material to be peeled and / or functionalized, - A step of arranging a second electrode outside the liquid, wherein at least one portion of the second electrode faces the surface of the liquid, - A step of generating plasma between at least one portion of the second electrode facing the surface of the liquid and the surface of the liquid by applying a pulse voltage difference between the first electrode and the second electrode, A method including this is provided.

[0008] Preferably, the voltage of the first electrode is higher than the voltage of the second electrode. The voltage of the first electrode can be lower than the voltage of the second electrode in order to increase peeling more than functionalization. The voltage of the first electrode can be lower than the voltage of the second electrode in order to reduce or cease functionalization. In other words, the voltage of the first electrode can be lower than the voltage of the second electrode mainly or exclusively for performing peeling of the layer material during the implementation of the method of the present invention.

[0009] According to the present invention, "lamellar" means a material body containing sheets parallel to the structure.

[0010] A part of the second electrode and / or the first electrode can be arranged in the gas in contact with the surface of the liquid.

[0011] At least one part of the second electrode facing the surface of the liquid is - the end of the second electrode, and / or - all or part of the surface of the electrode arranged facing the surface of the liquid.

[0012] According to the present invention, - the voltage difference between the first electrode and the second electrode is greater than 1000 volts, and / or - the distance d1 between at least one part of the second electrode facing the surface of the liquid and the surface of the liquid is greater than 1 μm, and / or - the time for applying the voltage difference between the first electrode and the second electrode is longer than 10 picoseconds, and / or - the time interval between two consecutive applications of the voltage difference between the first electrode and the second electrode is longer than 0.1 nanoseconds, and / or - the pressure of the gas in which the second electrode is arranged is greater than 1 Pascal (Pa) and / or less than 1·10 7 Pa,

[0013] Preferably, to generate plasma, i.e., to satisfy the gas breakdown condition, the voltage difference between the first electrode and the second electrode can be adapted according to the product of the gas pressure and the distance d1, or the opposite product.

[0014] Preferably, the gas in which the second electrode is disposed is a gas in contact with the surface of the liquid.

[0015] The gas in which the second electrode is disposed can be, as non-limiting examples, air, nitrogen, noble gases such as xenon, krypton, argon, neon or helium, or a gas mixture.

[0016] The first electrode and / or the second electrode can preferably contain a refractory material in a significant proportion.

[0017] The first electrode and / or the second electrode can be mainly or essentially composed of a refractory material.

[0018] The first and second electrodes can contain tungsten and / or carbon.

[0019] [[ID=​​​​​​​​​​​The layered material to be exfoliated and / or functionalized may include graphite and / or graphene material, and the exfoliated and / or functionalized object may consist of graphene.

[0023] Within the framework of applications, graphene is considered to consist of fewer than 25 sheets.

[0024] The layered material to be peeled and / or functionalized may have at least one dimension greater than 100 nanometers.

[0025] The peeled and / or functionalized layered material may have one dimension greater than 100 nanometers, two dimensions greater than 100 nanometers, or three dimensions greater than 100 nanometers.

[0026] The aforementioned method, - By increasing or decreasing the voltage difference between the first electrode and the second electrode, the peeling and / or functionalization of the layered material contained in the liquid is increased, and / or - By reducing or increasing the voltage difference between the first electrode and the second electrode, the peeling and / or functionalization of the layered material contained in the liquid is reduced. Therefore, the voltage difference between the first electrode and the second electrode is adjusted, and / or - ·By reducing the dielectric breakdown voltage in the gas, the peeling and / or functionalization of the layered material contained in the liquid is increased, and / or - By increasing the dielectric breakdown voltage in the gas, the peeling and / or functionalization of the layered material contained in the liquid is reduced. Therefore, to adjust the properties of the gas on which the second electrode is placed, and / or the pressure of the gas on which the second electrode is placed, and / or - By adding one or more acids to lower the pH, and / or by adding one or more salts to increase the conductivity of the liquid, the peeling and / or functionalization of the layered material contained in the liquid is increased, and / or - By adding one or more bases to increase the pH, and / or by lowering the salinity of the liquid to reduce the conductivity of the liquid, the peeling and / or functionalization of the layered material contained in the liquid is reduced. Therefore, to adjust the properties of the liquid containing the layered material that is peeled and / or functionalized, and / or the conductivity of the liquid containing the layered material that is peeled and / or functionalized, and / or - Increase the surface area of ​​the second electrode interacting with the plasma, thereby increasing the delamination and / or functionalization of the layered material contained in the liquid, and / or - By reducing the surface area that leaks and / or collects charges interacting with the plasma, the peeling and / or functionalization of the layered material contained in the liquid is reduced. This may include adjusting the surface area of ​​the second electrode.

[0027] Preferably, unless otherwise stated in this application, adjustments to parameters that have the effect of increasing (or individually decreasing) peeling and / or functionalization will not have the effect of decreasing (or individually decreasing) peeling and / or functionalization.

[0028] An acid can refer to a species that can behave like an acid in an acid-base reaction, and a base can refer to a species that can behave like a base in an acid-base reaction. In particular, a base is a species that contains one or more protons (H + Acids are chemical species that can accept one or more protons (H). + This can mean a chemical species that can provide ).

[0029] According to the present invention, adjustments may be design changes or adaptations.

[0030] According to the present invention, an increase or decrease in peeling and / or functionalization can be defined as an increase or decrease in the rate of peeling and / or the rate of functionalization.

[0031] Preferably, the above method can be carried out at atmospheric pressure.

[0032] The aforementioned method, - By reducing the distance between at least one portion of the second electrode facing the surface of the liquid and the surface of the liquid, the homogeneous regime or filamentary regime of the layered material contained in the liquid is promoted, thereby increasing the peeling and / or functionalization, and / or - By increasing the distance between at least one portion of the second electrode facing the surface of the liquid and the surface of the liquid, the homogeneous regime or filamentary regime of the layered material contained in the liquid is promoted, thereby reducing the peeling and / or functionalization. Therefore, the distance d1 between at least one portion of the second electrode facing the surface of the liquid and the surface of the liquid is adjusted, and / or - By increasing the time for which the voltage is applied between the first electrode and the second electrode, the peeling and / or functionalization of the layered material contained in the liquid is increased, and / or - By reducing the time for which the voltage is applied between the first electrode and the second electrode, the peeling and / or functionalization of the layered material contained in the liquid is reduced. Therefore, the time for which the voltage difference between the first electrode (5) and the second electrode is applied is adjusted, and / or - By increasing the frequency between two consecutive applications of the voltage difference, the peeling and / or functionalization of the layered material contained in the liquid is increased, and / or - By reducing the frequency between two consecutive applications of the voltage difference, the peeling and / or functionalization of the layered material contained in the liquid is reduced. This may include adjusting the frequency between two consecutive applications of the voltage difference.

[0033] When adjusting distance d1, decreasing distance d1 can have the same effect as increasing distance d1, as a non-limiting example of increasing functionality. This effect is due to a change in the plasma discharge regime, for example, a transition from a uniform discharge regime to a filament discharge regime (or vice versa).

[0034] According to the present invention, an apparatus for peeling and / or functionalizing a layered material, - At least one first electrode comprising at least one portion intended to be immersed in a liquid containing the layered material to be peeled and / or functionalized, - At least one second electrode intended to be positioned outside the liquid, wherein at least one portion of the at least one second electrode is intended to face the surface of the liquid, - The apparatus also includes a pulse power generator that emits an electrical pulse between the at least one first electrode and the at least one second electrode, the pulse power generator being positioned to apply a voltage difference greater than 1000 volts between the at least one first electrode and the at least one second electrode.

[0035] Preferably, the at least one first and second electrodes are arranged facing each other, and / or the generator is arranged so that plasma is not generated between the at least one first electrode and the at least one second electrode.

[0036] Preferably, the plasma does not extend between the surface of the at least one first electrode and the surface of the at least one second electrode. The surface of the at least one second electrode may be at least one portion of the at least one second electrode intended to be positioned opposite the surface of the liquid.

[0037] Preferably, the at least one first and second electrodes are arranged opposite to each other and / or the generating device is arranged so as to generate plasma starting from at least one part of the at least one second electrode intended to be arranged facing the surface of the liquid. Preferably, the plasma starts from at least one part of the at least one second electrode facing the surface of the liquid and is generated towards the surface of the liquid in which at least one part of the at least one first electrode is intended to be immersed.

[0038] The distance d2 separating the at least one first electrode and the second electrode is greater than the distance indicated by d E1E2 The at least one first electrode and the second electrode can be arranged relative to each other such that the distance between them is greater than the distance indicated by d, from which and below this, a plasma begins to be generated in a spatial region extending along the distance d E1E2 between the at least one first electrode and the second electrode, and / or - In a region extending along the distance d2 between the at least one first electrode and the second electrode, a voltage V at which plasma is generated is applied between the at least one first electrode and the second electrode. cl-elec The generating device can be arranged to apply a voltage V smaller than V between the at least one first electrode and the second electrode.

[0039] Preferably, for a given gas and gas pressure, - And for the voltage difference indicated by V applied between the at least one first electrode and the second electrode, the relative arrangement of the at least one first electrode and the second electrode with respect to each other is such that the distance d2 between the at least one first electrode and the second electrode is greater than the distance indicated by d app separating the at least one first electrode and the second electrode, from which and below this, a plasma begins to be generated in a spatial region extending along the distance d E1E2 between the at least one first electrode and the second electrode, and / or E1E2 - The at least one first electrode and the second electrode are separated by d ​elec For an arrangement of at least one first electrode and a second electrode facing each other, separated by a predetermined distance shown by , in a region extending along the distance d2 between the at least one first electrode and the second electrode, the voltage at which plasma is generated is V cl-elec The generator is positioned to apply a smaller voltage V between the at least one first electrode and the second electrode.

[0040] Regarding the arrangement of the at least one first electrode and the second electrode, and / or the voltage V applied between the at least one first electrode and the second electrode, the dielectric breakdown voltage V of the gas in the spatial region extending along the distance d2 between the at least one first electrode and the second electrode cl-elec The dielectric breakdown voltage V of the gas in a spatial region extending along a distance d1 between at least one portion of the at least one second electrode, which is intended to be positioned opposite the surface of the liquid, and the surface of the liquid. cl-liq It is preferable that it be larger.

[0041] In other words, the voltage difference applied between the at least one first electrode and the at least one second electrode, and / or the relative arrangement of the at least one first electrode and the second electrode, is such that no plasma is generated in the spatial region extending between the at least one first electrode and the at least one second electrode.

[0042] Preferably, only a portion of the second electrode, referred to as the immersion portion, is intended to be located in the gas.

[0043] According to the present invention, "placing an object, such as a part of an electrode, in a medium such as a gas or liquid" means that the surface of the object is in direct contact with the medium.

[0044] In a non-restrictive example, the at least one first electrode and / or the at least one second electrode may be rectangular or plate-shaped.

[0045] The at least one first electrode and / or the at least one second electrode may be a single electrode or may include a plurality of electrodes.

[0046] The at least one first electrode and / or the at least one second electrode may be a group of electrodes connected to each other or a group of electrodes that are not connected. The at least one first electrode and / or the at least one second electrode may be electrodes of a network.

[0047] The apparatus may include a single generator or multiple generators.

[0048] The apparatus may include a plurality of generators, and the at least one first electrode and / or the at least one second electrode preferably include a plurality of electrodes, and each generator is connected to one or more electrodes among the plurality of electrodes.

[0049] Preferably, the voltage of the first electrode is greater than the voltage of the second electrode.

[0050] The at least one first electrode is - A portion intended to be located in the gas in which the at least one second electrode is located, separated from the at least one second electrode by a distance d2, wherein the distance d2 is adapted according to the properties and / or pressure of the gas in which the at least one second electrode is located, such that the voltage difference applied by the generator is less than the dielectric breakdown voltage in the gas, or - This may include the absence of the portion intended to be located in the gas in which at least one second electrode is positioned.

[0051] The distance d2 can be defined as the shortest distance separating the at least one first electrode from one portion of the at least one second electrode that is intended to be located in the gas in which the at least one second electrode is placed.

[0052] Preferably, the portion of the second electrode intended to be located in the gas in which the at least one second electrode is positioned is located in the portion of the second electrode intended to be immersed.

[0053] The entirety of the at least one first electrode may be intended to be immersed in a liquid. The absence of a portion of the at least one first electrode intended to be located in a gas may correspond to the case in which the entirety of the at least one first electrode is immersed in the liquid.

[0054] The at least one first electrode is rectangular in shape, ·mainly - A plane p1 including the at least one portion of the at least one second electrode, which is intended to be positioned opposite the surface of the liquid, - The end of the at least one portion of the at least one first electrode that is intended to be immersed in the liquid, It extends in the direction b1 connecting the two, The portion of the at least one first electrode, including the portion of the at least one first electrode intended to be immersed in the liquid, protrudes in the direction b1 with respect to the plane p1, and the distance d3 between the end of the portion of the at least one first electrode intended to be immersed in the liquid and the plane p1 is greater than 2 mm.

[0055] The at least one second electrode and / or the at least one first electrode and the at least one second electrode can be rectangular in shape.

[0056] According to the present invention, - The distance d1 between the plane p1 and the surface of the liquid can be greater than 1 μm. - The distance d4 between the plane p2 including the end of the at least one portion of the at least one first electrode intended to be immersed in the liquid and the surface of the liquid is equal to the difference between d3 and d1 and greater than 1 mm.

[0057] The apparatus may be an apparatus comprising the liquid containing the layered material to be peeled and / or functionalized, wherein the at least one first and second electrode are positioned opposite to the surface of the liquid, and / or the generator is positioned to apply a voltage difference adapted to generate plasma between the at least one portion of the at least one second electrode positioned opposite the surface of the liquid and the surface of the liquid.

[0058] Preferably, the arrangement of the at least one first electrode and the second electrode, and / or the voltage V applied between the at least one first electrode and the second electrode, - Dielectric breakdown voltage V of the gas in the spatial region extending along the distance d2 between the at least one first electrode and the second electrode cl-elec The dielectric breakdown voltage V of the gas in a spatial region extending along a distance d2 between at least one portion of the at least one second electrode, which is intended to be positioned opposite the surface of the liquid, and the surface of the liquid. cl-liq Larger, - The voltage V applied between the at least one first electrode and the second electrode is Voltage V cl-liq Larger, and Voltage V cl-elec Let's assume it's smaller.

[0059] The apparatus according to the present invention is preferably configured to carry out the method according to the present invention. Any feature of the method according to the present invention can be integrated into the apparatus according to the present invention.

[0060] Preferably, the method according to the present invention is carried out using the apparatus according to the present invention. Any feature of the apparatus according to the present invention can be integrated into the method according to the present invention. [Brief explanation of the drawing]

[0061] Further advantages and features of the present invention will become apparent upon reading the detailed description of non-limiting embodiments and examples in reference to the accompanying figures.

[0062] [Figure 1] Figure 1 is a schematic diagram showing an embodiment of the apparatus according to the present invention. [Figure 2] Figure 2 is a graph showing the changes in the pH of the solution, the electrical conductivity of the solution, and the temperature of the solution as a function of time while the method according to the present invention is being carried out. [Figure 3] Figure 3 shows a photograph comparing the layered filler treated by this method in a suspension with a reference layered filler in a suspension. [Figure 4] Figure 4 shows the Raman spectra of the layered filler before and after treatment. [Modes for carrying out the invention]

[0063] The embodiments described below are not limiting, and variations of the present invention may be realized by including only a selection of features described below, separated from other features described below (even if this selection is separated from a single sentence containing these other features) (where this selection of features is sufficient to provide a technical advantage or to differentiate the present invention from the prior art). This selection includes at least one preferably functional feature, which does not involve structural details or involves only a portion of structural details (where this portion alone is sufficient to provide a technical advantage or to differentiate the present invention from the prior art).

[0064] Referring to Figure 1, the apparatus 1 and method according to the present invention will be described. The layered material used when carrying out the exfoliation and / or functionalization method of the present invention using the apparatus 1 is a graphite filler sold under the trade name "KNG-180" by "Knano" Corporation. This graphite filler has a macroscopic size, and its dimensions are greater than 100 nanometers. The exfoliated and / or functionalized object is made of graphene. The exfoliated and / or functionalized object may include graphene and graphene materials. The method is carried out at ambient temperature. The gas 2 is air 2, and it is intended that at least one second electrode 6, according to this embodiment, a single second electrode 6 is placed therein. The pressure of the gas 2 in which the second electrode 6 is placed is greater than 1 Pascal (Pa) and / or 1.10 7 Less than Pa. According to this embodiment, air 2 is atmospheric pressure. Liquid 3 is demineralized water 3 containing a layered material, and is intended to immerse at least one first electrode 5, or at least one portion 4 of a single first electrode 5 according to this embodiment. The method is carried out with a solution in which the volume of liquid 3 is 300 ml and the mass of graphite filler is 200 mg. Unless otherwise indicated, the method is carried out for 1 hour. The second electrode 6 is intended to be placed outside the liquid 3. At least one portion 7 of the second electrode 6 is intended to face the surface 8 of the liquid 3. Apparatus 1 includes a pulse power generator 10 that emits electrical pulses between the first electrode 5 and the second electrode 6. The pulse power generator 10 is positioned to apply a voltage difference greater than 1000 volts between the first electrode 5 and the second electrode 6. The voltage difference is 6 kV according to this embodiment. Preferably, the voltage of the first electrode 5 is greater than the voltage of the second electrode 6. According to this embodiment, the second electrode 6 is connected to ground, and the first electrode 5 is connected to the pulse generator 10.

[0065] When this method is implemented, a portion 4 of the first electrode 5 is immersed in the liquid 3. The first electrode 5 and the second electrode 6 are positioned facing each other, and / or a generator 10 is positioned to apply a suitable voltage difference to generate plasma 9 between a portion 7 of the second electrode 6, which is positioned facing the surface 8 of the liquid 3, and the surface 8 of the liquid 3. In practice, the onset of plasma is called dielectric breakdown and occurs under conditions that follow Paschen's law, i.e., when the product of the gas pressure and the distance between electrodes is the minimum value of the gas's dielectric breakdown voltage. Typically, in a mixture of gases 2 or a pure gas 2, a voltage greater than the dielectric breakdown voltage is combined, and a distance of a few millimeters is selected between the second electrode 5 and the surface 8 of the liquid 3 to ensure plasma discharge 9.

[0066] The first electrode 5 and the second electrode 6 are positioned opposite each other, and / or the generator 10 is positioned so that plasma is not generated between the first electrode 5 and the second electrode 6. By applying a voltage difference between the first electrode 5 and the second electrode 6, plasma 9 is generated between the portion 7 of the second electrode 6 facing the surface 8 of the liquid 3 and the surface 8 of the liquid 3. As a non-limiting example, the plasma generated by the present invention is approximately 1 mm in size. 3 It can be considered a small plasma. Its size is 10 cm. 3 The plasmas described above can be considered large-scale plasmas.

[0067] The distance d1 between the portion 7 of the second electrode 6, which is intended to face the surface 8 of the liquid 3, and the surface 8 of the liquid 3 is greater than 1 μm, and according to this embodiment, it is 1 mm. Apparatus 1 includes a nanosecond chopper 11, which is positioned to apply a voltage between the first electrode 5 and the second electrode 6 for an application time longer than 10 picoseconds. According to this invention, the application time is 1 μsecond. The average power of the pulse is approximately 36 W. The nanosecond chopper 11 is positioned such that the time interval between applying the voltage difference twice consecutively between the first electrode 5 and the second electrode 6 is preferably longer than 0.1 n seconds. According to this embodiment, this time interval is approximately 170 μseconds. The advantage of a high-voltage pulse regime (typically voltage greater than 1000 volts) is that the process of delaminating the graphite is accelerated by igniting a shock wave during plasma dielectric breakdown 9 in atmospheric pressure air 2. Subsequently, the graphite filler located on the surface 8 of the liquid 3 can undergo mechanical separation of the graphene plane. Another advantage of this discharge regime is that it enables high-energy plasma functionalization in a way that does not consume a very large amount of energy, using an average power of 10 to 120 W depending on the discharge conditions. Since it only requires the dielectric breakdown voltage of gas 2 (air in this case), this method is allowed to proceed until a current of several amperes is reached.

[0068] A portion 12 of the first electrode 5 is intended to be located in the gas in which the second electrode is placed. The portion 12 is separated from the second electrode 6 by a distance d2. The distance d2 is adapted according to the properties and / or pressure of the gas in which the second electrode 6 is placed, such that the voltage difference applied by the generator 10 is less than the dielectric breakdown voltage in the gas.

[0069] According to this embodiment, the first electrode 5 and the second electrode 6 are rectangular in shape. The first electrode 5 is • A plane p1 including a portion 7 of the second electrode 6, which is intended to be positioned opposite the surface 8 of the liquid 3, • The end 13 of the portion 4 of the first electrode 5, which is intended to be immersed in liquid 3, It mainly extends in the direction b1 that connects them.

[0070] The portion of the first electrode 5, including the portion 4 intended to be immersed in the liquid 3, protrudes in direction b1 with respect to a plane p1. The distance d3 between the end 13 of the portion 4 of the first electrode 5 intended to be immersed in the liquid 3 and the plane p1 is greater than 2 mm. The distance d4 between the plane p2, which includes the end 13 of the portion 4 of the first electrode 5 intended to be immersed in the liquid 3, and the surface of the liquid 3 is equal to the difference between d3 and d1 and is greater than 1 mm.

[0071] Figure 2 illustrates the effect of this method on solution 3. The aqueous phase 3 undergoes significant changes in its initial intrinsic properties, particularly its composition, resulting in changes in pH and electrical conductivity. This change in liquid 3 composition is due to the interaction between plasma 9 and liquid 3, more specifically to the solvation of species originating from plasma 9, such as electrons, ions, and other radicals or energy species, on the surface 8 of liquid 3. The dissipation of medium 3, its acidification, and the resulting temperature rise are equally changing parameters, facilitating the process of exfoliating graphite on the surface and within the volume of liquid 3, as well as the reaction mechanism that functionalizes the graphene plane.

[0072] Figure 3 shows the effectiveness of the functionalization effect of this method on the obtained graphene nanofillers. The precipitation rate of the nanofiller suspension is an indicator of the surface state of the nanofillers in the suspension. Functionalization of nanofillers involves introducing chemical groups containing oxygen atoms, such as hydroxyl, carbonyl, and / or carboxyl, particularly polar groups or functional groups, to the surface of the nanofillers, especially promoting the suspension and stability of the nanofillers. In Figures 3a), 3b), and 3c), the sample on the left is an aqueous solution of nanofillers suspended by this method, and the sample on the right is an aqueous solution of nanofillers sold under the trade name "KNG-180" by "Knano" Corporation. Figures 3a), 3b), and 3c) show images of the samples immediately after stirring, after 5 minutes of stirring, and after 1 hour of stirring, respectively. After 1 hour, no significant precipitation is observed in the sample containing nanofillers in the suspension obtained by this method. On the other hand, after 5 minutes, significant precipitation is observed in the reference nanofiller-containing suspension solution. This demonstrates the effectiveness of the method for functionalizing nanofillers according to the present invention. This modification of the filler surface state is also confirmed by the detection of carboxylic acid groups on the surface of the graphene plane, which is revealed by thermogravimetric analysis combined with mass spectrometry and X-ray photoelectron spectroscopy. These groups can then be used to facilitate specific functionalization treatments or the dispersion of graphene planes within a polymer matrix.

[0073] In Figure 4, the Raman spectrum for the initial graphite filler before performing this method is shown in the left figure. The Raman spectrum for the graphene nanofiller obtained after performing this method is shown in the right figure. The small degradation of the carbon plane is one-tenth the size of that observed when the latest chemical treatment is completed. "Defect rate" is "I D / I G This is evaluated by the ratio of the spectral bands represented by G, which is specific to the sp2 hybridization state of carbon, to the spectral bands represented by D, which are specific to defects.

[0074] Therefore, in modified embodiments in which the above-described embodiments can be combined, - The layered material to be exfoliated and / or functionalized includes clay material, transition metal chalcogenide, phyllosilicate and / or graphene material, and / or - The first electrode 5 and / or the second electrode 6 preferably contain a significant proportion of fire-resistant material and / or - The first electrode 5 and / or the second electrode 6 contain tungsten and / or carbon, and / or - The first electrode 5 is completely immersed in the liquid 2. Therefore, the first electrode 5 does not include the portion 12 that is intended to be located in the gas 2 in which the second electrode 6 is placed.

[0075] Furthermore, the different features, shapes, variations, and embodiments of the present invention can be combined with each other in various combinations, provided that they are not incompatible or mutually exclusive.

Claims

1. A method for peeling and / or functionalizing layered materials, - A step of immersing at least one portion (4) of the first electrode (5) in a liquid (3) containing the layered material to be peeled and / or functionalized, - A step of placing a second electrode (6) outside the liquid in a gas in contact with the surface of the liquid, wherein at least one portion (7) of the second electrode faces the surface (8) of the liquid, - A step of generating plasma (9) between at least one portion of the second electrode facing the surface of the liquid and the surface of the liquid by applying a pulse voltage difference between the first electrode and the second electrode, A method that includes this.

2. - The voltage difference between the first electrode (5) and the second electrode (6) is greater than 1000 volts, and / or - The distance d1 between the at least one portion (7) of the second electrode facing the surface (8) of the liquid (3) and the surface of the liquid is greater than 1 μm, and / or - The time for which the voltage difference between the first electrode and the second electrode is applied is longer than 10 picoseconds, and / or - The time interval between applying the pulse voltage difference between the first electrode and the second electrode twice in succession is longer than 0.1 n seconds, and / or - The pressure of the gas (2) on which the second electrode is placed is greater than 1 Pascal (Pa) and / or 1.10 ７ Smaller than Pa The method according to claim 1.

3. The method according to claim 1 or 2, wherein the first electrode (5) and / or the second electrode (6) preferably contain a fire-resistant material in a significant proportion.

4. The method according to any one of claims 1 to 3, wherein the first (5) and second (6) electrodes include tungsten and / or carbon.

5. The method according to any one of claims 1 to 4, wherein the layered material to be exfoliated and / or functionalized comprises graphite, clay material, transition metal chalcogenide, phyllosilicate and / or graphene material.

6. The method according to any one of claims 1 to 5, wherein the layered material to be peeled and / or functionalized comprises graphite and / or graphene material, and the peeled and / or functionalized object is made of graphene.

7. The method according to any one of claims 1 to 6, wherein the layered material to be peeled and / or functionalized has at least one dimension greater than 100 nanometers.

8. - By increasing or decreasing the voltage difference between the first electrode and the second electrode, the peeling and / or functionalization of the layered material contained in the liquid (3) is increased, and / or - By reducing or increasing the voltage difference between the first electrode and the second electrode, the peeling and / or functionalization of the layered material contained in the liquid is reduced. Therefore, the voltage difference between the first electrode (5) and the second electrode (6) is adjusted, and / or - • By reducing the dielectric breakdown voltage in the gas, the peeling and / or functionalization of the layered material contained in the liquid is increased, and / or - By increasing the dielectric breakdown voltage in the gas, the peeling and / or functionalization of the layered material contained in the liquid is reduced. Therefore, the properties of the gas (2) on which the second electrode is placed, and / or the pressure of the gas on which the second electrode is placed, and / or - By adding one or more acids to lower the pH of the liquid, and / or by adding one or more salts to increase the conductivity of the liquid, the peeling and / or functionalization of the layered material contained in the liquid is increased, and / or - By adding one or more bases to increase the pH of the liquid, and / or by lowering the salt concentration of the liquid to decrease the conductivity of the liquid, the peeling and / or functionalization of the layered material contained in the liquid is reduced. To that end, adjust the properties of the liquid containing the layered material that is peeled and / or functionalized, and / or the conductivity of the liquid containing the layered material that is peeled and / or functionalized. The method according to any one of claims 1 to 7, including the method described in any one of claims 1 to 7.

9. - By increasing the time for which the voltage between the first electrode and the second electrode is applied, the peeling and / or functionalization of the layered material contained in the liquid is increased, and / or - By reducing the time for which a voltage is applied between the first electrode and the second electrode, the peeling and / or functionalization of the layered material contained in the liquid is reduced. Therefore, the time for which the voltage difference between the first electrode (5) and the second electrode is applied is adjusted, and / or - By increasing the frequency between two consecutive applications of the voltage difference, the peeling and / or functionalization of the layered material contained in the liquid is increased, and / or - By reducing the frequency between two consecutive applications of the voltage difference, the peeling and / or functionalization of the layered material contained in the liquid is reduced. Therefore, the frequency between two consecutive applications of the voltage difference is adjusted. The method according to any one of claims 2 to 8, including the method described in any one of claims 2 to 8.

10. A device for peeling and / or functionalizing layered materials, - At least one first electrode (5) including at least one portion (4) intended to be immersed in a liquid (3) containing the layered material to be peeled and / or functionalized, - In the gas (2) in contact with the surface of the liquid, there is at least one second electrode (6) intended to be positioned outside the liquid, wherein at least one portion (7) of the at least one second electrode (6) is intended to face the surface (8) of the liquid, - A pulse power generator (10) that emits an electrical pulse between the at least one first electrode and the at least one second electrode, and further comprising a pulse power generator (10) positioned to apply a voltage difference greater than 1000 volts between the at least one first electrode and the at least one second electrode, An apparatus in which the at least one first and second electrodes are arranged opposite to each other, and / or the generator does not generate plasma between the at least one first electrode and the at least one second electrode.

11. The at least one first electrode (5) is - A portion (12) intended to be located in the gas (2) in which the at least one second electrode (6) is placed, and separated from the at least one second electrode by a distance d2, wherein the distance d2 is adapted according to the properties and / or pressure of the gas in which the at least one second electrode is placed, such that the voltage difference applied by the generator is less than the dielectric breakdown voltage in the gas, or - The absence of the portion intended to be located in the gas in which at least one second electrode is positioned, The apparatus according to claim 10, including the following:

12. The at least one first electrode (5) is rectangular in shape, ·mainly - A plane p1 including the at least one portion (7) of the at least one second electrode (6) which is intended to be positioned opposite the surface (8) of the liquid (3), - The end (13) of the at least one portion (4) of the at least one first electrode which is intended to be immersed in the liquid, It extends in the direction b1 connecting the two, - The portion of the at least one first electrode, including the portion of the at least one first electrode intended to be immersed in the liquid, protrudes in the direction b1 with respect to the plane p1, and the distance d3 between the end of the portion of the at least one first electrode intended to be immersed in the liquid and the plane p1 is greater than 2 mm. The apparatus according to claim 10 or 11.

13. - The distance d1 between the plane p1 and the surface (8) of the liquid (3) is greater than 1 μm. - The distance d4 between the plane p2 including the end (13) of the at least one portion (4) of the at least one first electrode (5) intended to be immersed in the liquid and the surface of the liquid is equal to the difference between d3 and d1 and greater than 1 mm. The apparatus according to claim 12.

14. Apparatus according to any one of claims 10 to 13, comprising the liquid (3) containing the layered material to be peeled and / or functionalized, wherein the at least one first (5) and second (6) electrodes are positioned opposite to each other, and / or the generator (10) is positioned, to apply a voltage difference adapted to generate plasma (9) between the at least one portion (7) of the at least one second electrode positioned opposite to the surface of the liquid and the surface of the liquid.

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