Use of a reactive composition as an adhesion primer precursor between a fluoropolymer and a substrate, methods of producing coatings, coated substrates and devices comprising same

Abstract

The invention relates to a use of a reactive composition as an adhesion primer precursor between a substrate and a coating comprising at least one fluoropolymer, said reactive composition comprising at least one polymer PG comprising a repeating unit derived from methyl methacrylate and at least one repeating unit comprising at least one reactive function, said at least one repeating unit derived from methyl methacrylate representing at least 40% by weight of the weight of said at least one polymer PG; said reactive composition comprising a photoinitiator and optionally a synergistic coinitiator such as derivatives comprising at least one amine or silyl function.

Description

[0001] Description

[0002] Title: Use of a reactive composition as a precursor of adhesion primer between a fluoropolymer and a substrate, methods of manufacturing coatings, coated substrates and devices comprising them

[0003] Field of invention

[0004] The invention relates to the field of adhesion of a fluoropolymer to a surface. More particularly, the invention relates to the use of a reactive composition, in particular a crosslinkable composition, on the surface of a substrate as a precursor of an adhesion primer between a fluoropolymer coating and a substrate.

[0005] The invention also relates to a method for treating a substrate, intended to increase its adhesion properties with a fluoropolymer. The invention also relates to a method for manufacturing a coating based on fluoropolymer(s) on a treated substrate.

[0006] The invention also relates to composites, in particular those capable of being obtained by the two aforementioned processes.

[0007] The invention finally relates to a device comprising one of these composites.

[0008] Technical background

[0009] Fluoropolymers, for example those based on vinylidene fluoride CF2=CH2 (VDF) such as PVDF (polyvinylidene fluoride) are known to offer excellent mechanical stability properties, very high chemical inertness, as well as good resistance to aging. These qualities are exploited for very varied application areas. In particular, certain fluorinated polymers, such as vinylidene fluoride (VDF) based polymers, such as P(VDF-TrFE), P(VDF-TrFE-CTFE), P(VDF-TrFE-CFE) are used for their electroactive properties, particularly in electronic devices.

[0010] However, due to their high chemical inertness, fluoropolymers suffer from an adhesion problem on substrates, particularly on metallic substrates, which can be particularly problematic for certain applications. However, if the fluoropolymer is detached or delaminated from the surface of the substrate with which it is in direct contact, it can no longer fulfill its initial function (transformation of a physical quantity for a transducer, binder for an electrode, protective coating, thermal insulation, etc.). For example, a transducer formed by an electroactive fluoropolymer placed between two electrodes will no longer function or will function poorly if the fluoropolymer is detached or delaminated, even partially, from its electrodes. It is recalled that a polymer is said to be electroactive if it exhibits a response (deformation, temperature variation, etc.)) when an electric field is applied and / or if a stress (mechanical, thermal, etc.) induces an electrical response within the material.

[0011] A solution to overcome the problem of adhesion between a substrate and a fluoropolymer is generally to interpose a layer of primer between the substrate and the fluoropolymer to improve adhesion. For example, it is known from the prior art to use the primer DOWSIL™ Primer C, marketed by the Dow Chemical Company. As demonstrated in the examples, this adhesion primer proves to have limited performance with at least some fluoropolymers.

[0012] There is currently a need to provide new adhesion primers that can substantially increase the adhesion of a fluoropolymer to a substrate.

[0013] Objectives of the invention

[0014] An objective of the invention is to provide a reactive composition which can be used as an adhesion primer precursor to improve the adhesion of a fluoropolymer to a substrate.

[0015] According to certain embodiments, the adhesion primer obtained must modify as little as possible the useful properties of said fluoropolymer. According to certain embodiments where the fluoropolymer has electroactive properties, an objective of the invention is to essentially retain its electroactive properties.

[0016] Another objective of the invention is to provide a method for treating a substrate, intended to increase its adhesion properties with regard to fluorinated polymer(s). According to certain embodiments, an objective of the invention is to provide such a method which is easy and / or rapid and / or inexpensive to implement.

[0017] Another objective of the invention is also to provide a method for manufacturing a coating of a fluoropolymer on a substrate covered with an adhesion primer which is easy and / or quick and / or inexpensive to implement.

[0018] According to certain embodiments, the aforementioned methods must be able to be implemented under mild conditions.

[0019] According to certain embodiments, the aforementioned manufacturing methods are efficient, and can in particular be implemented sufficiently quickly. Another objective of the invention is to provide a composite comprising an adhesion primer adhering well to a substrate and intended to adhere well to a fluoropolymer.

[0020] Another objective of the invention is to provide a composite comprising a coating of a fluoropolymer adhering well to a substrate covered with an adhesion primer and / or a device incorporating this composite.

[0021] Summary of the invention

[0022] The invention relates, according to a first aspect, to the use of a reactive composition as a precursor of adhesion primer between a substrate and a coating comprising at least one fluorinated polymer, said reactive composition comprising at least one PG polymer comprising a repeating unit derived from methyl methacrylate and at least one repeating unit comprising at least one reactive function, said at least one repeating unit derived from methyl methacrylate representing at least 40% by weight of the weight of said at least one PG polymer.

[0023] The inventors of the present invention have noticed that such a PG polymer, used as an adhesion primer precursor, made it possible to improve the adhesion of the fluoropolymer to a substrate in an interesting way. Without being bound by theory, it seems that this remarkable improvement in adhesion is due to the double condition fulfilled by the PG primer: a good affinity for the fluoropolymer, and at least one reactive function making it possible to crosslink said PG polymer on the surface of the substrate.

[0024] According to certain embodiments, said at least one repeating unit derived from methyl methacrylate representing at least 45%, or at least 50%, or at least 55%, or at least 60% by weight of said at least one PG polymer.

[0025] According to certain embodiments, said at least one reactive function of at least one repeating unit of said at least one PG polymer is a photo- and / or thermoreactive function.

[0026] According to certain embodiments, said reactive composition comprises a photoinitiator and optionally a synergistic coinitiator such as derivatives comprising at least one amine or silyl type function.

[0027] According to certain embodiments, said reactive composition comprises a thermal initiator.

[0028] According to certain embodiments, said at least one reactive function of at least one repeating unit of said at least one PG polymer is chosen from groups of the oxirane, aziridine or thiirane type. According to certain variants of these embodiments, said reactive composition may comprise a photoinitiator, the photoinitiator being chosen from acid-generating photoinitiators (PAG), preferentially from onium salts, in particular sulfonium, iodonium and pyridinium salts, ferrocene derivatives, nitrobenzyl ester derivatives, sulfones, aryl phosphates, derivatives comprising N-hydroxysuccinimide sulfonate functions, sulfonic acid esters; and base-generating photoinitiators (PBG), preferentially from derivatives comprising functions of the 0-acyloxime, benzoyloxycarnoyl or o-nitrobensoyloxycarbonyl type, or formamide.According to other variants of these embodiments, said reactive composition may comprise a thermal initiator, the thermal initiator being chosen from chemical derivatives for generating a thermally activated acid proton, such as ammonium salts such as triflate, ammonium trifluoroacetate or ammonium trifluoromethanesulfonate, pyridinium salts such as pyridinium paratoluenesulfonate, phosphoric or sulfuric or sulfonic acids such as p-toluenesulfonic acid 4-nitrobenzyloate, or onium salts such as iodonium salts such as bis-4-tert-butylphenyliodonium hexafluorophosphate or phosphonium salts, or imidazolium salts.

[0029] According to certain embodiments, said at least one PG polymer comprises a repeating unit resulting from the polymerization of glycidyl methacrylate. According to certain embodiments, said at least one reactive function of at least one repeating unit of said at least one PG polymer is chosen from a carbon-carbon double bond and a carbon-carbon triple bond.

[0030] According to certain variants of these embodiments, said reactive composition comprises a photoinitiator, preferentially chosen from compounds having a function of the aryl-ketone type, α-amino ketones, benzylic acetals, xanthones or thioxanthones, phosphine oxides, and titanocene-type derivatives.

[0031] According to other variants of these embodiments, said reactive composition may comprise a thermal initiator, the thermal initiator being a radical initiator chosen from organic peroxide type derivatives such as benzoyl peroxide, or derivatives comprising an azo type chemical function such as azobisisobutyronitrile (AIBN), or even alkyl halide type derivatives.

[0032] According to certain embodiments, said at least one PG polymer comprises at least one repeating unit other than that derived from methyl methacrylate and that(s) comprising said at least one reactive function, said at least one other repeating unit being capable of grafting with said at least one reactive function (crosslinking) and being chosen from the units resulting from the polymerization of non-(meth)acrylic silylated vinyl monomers, silylated styrenic monomers, acrylic acid, methacrylic acid, and alkyl esters of acrylic or methacrylic acid whose alkyl chain is substituted by at least one group chosen from -SiHs, alkylsilane, oxysilane, phosphonate, phosphonic acid, alcohol, amino, thiol, thioester.

[0033] Advantageously, said at least one other repeating unit capable of grafting with said at least one reactive function is chosen from units derived from the polymerization of acrylic acid, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate or 2-hydroxypropyl acrylate, methacrylic acid, and hydroxyalkyl methacrylates such as 2-hydroxyethyl methacrylate or 2-hydroxypropyl methacrylate. Said at least one other repeating unit capable of grafting with said at least one reactive function may in particular be derived from 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate. said at least one PG polymer is a linear polymer.

[0034] According to certain embodiments, said at least one PG polymer is a gradient or statistical type copolymer.

[0035] In these embodiments, said at least one PG polymer may comprise from 5% to 30% by weight of said at least one repeating unit comprising at least one reactive function, relative to the weight of the PG polymer.

[0036] In these embodiments, said at least one PG polymer may comprise from 40% to 95% by weight of repeating unit resulting from the polymerization of methyl methacrylate, relative to the weight of the PG polymer.

[0037] In these embodiments, said at least one PG polymer may comprise at least one other repeating unit capable of grafting with said at least one reactive function as already described, said at least one other unit capable of grafting with said at least one reactive function representing from 1% to 30% by weight relative to the weight of the PG polymer.

[0038] According to certain embodiments, said at least one PG polymer is a block copolymer.

[0039] In these embodiments, said at least one PG polymer may comprise at least one block A comprising a repeating unit derived from methyl methacrylate and at least one block B comprising said at least one repeating unit comprising at least one reactive function.

[0040] In these embodiments, said at least one block A may advantageously not comprise said at least one repetition unit comprising at least one reactive function.

[0041] In these embodiments, said at least one block B may advantageously not comprise a repeating unit derived from methyl methacrylate.

[0042] In these embodiments, the PG polymer may be a P(AbB) type block polymer where A and B are the blocks as described above.

[0043] In these embodiments, said at least one PG polymer may comprise from 0.5% to 20% by weight of said at least one repeating unit comprising at least one reactive function, relative to the weight of the PG polymer.

[0044] In these embodiments, said at least one PG polymer may comprise from 60% to 99.5% by weight of repeating unit derived from methyl methacrylate, relative to the weight of the PG polymer.

[0045] In these embodiments, said at least one PG polymer may comprise at least one other repeating unit capable of grafting with said at least one reactive function as already described, said at least one other repeating unit capable of grafting with said at least one reactive function representing from 0.5% to 20% by weight relative to the weight of the PG polymer.

[0046] In these embodiments, said at least one PG polymer may comprise at least one block A comprising a repeating unit derived from methyl methacrylate and at least one block B comprising said at least one repeating unit comprising at least one reactive function and said at least one other repeating unit capable of grafting with said at least one reactive function. Advantageously, said at least one block A does not comprise said at least one other repeating unit capable of grafting with said at least one reactive function.

[0047] According to certain embodiments, said PG polymer has a number average molar mass of 1,000 g / mol to 150,000 g / mol, preferably of 1,500 g / mol to 100,000 g / mol, and more preferably of 2,000 g / mol to 50,000 g / mol.

[0048] According to particular embodiments, said at least one PG polymer can be chosen from:

[0049] - a random or gradient copolymer resulting from the polymerization of methyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate, - a random or gradient copolymer of methyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate and tert-butyl methacrylate,

[0050] - an AB type block copolymer, where block A is a methyl methacrylate block and block B is a block resulting from the polymerization of glycidyl methacrylate and 2-hydroxyethyl methacrylate, and

[0051] - their mixture.

[0052] The proportions of the different monomers may advantageously be those as described in more detail in certain embodiments for a statistical or gradient polymer or for a block polymer.

[0053] According to certain embodiments, said reactive composition comprises a compound M not comprising said reactive function and comprising a function chosen from: nitroxy, -SiHs, alkylsilane, oxysilane, phosphonate, phosphonic acid, alcohol, amino, thiol, and thioester.

[0054] According to certain embodiments, said at least one fluoropolymer comprises at least 40 mol% of repeating unit derived from vinylidene fluoride, relative to the total sum of moles of repeating units constituting said polymer, and optionally at least one repeating unit derived from a monomer X, other than vinylidene fluoride, having the formula CXiX2=CX3X4, in which each group Xi, X2, X3 and X4 is independently chosen from H, Cl, F, Br, I and C1-C3 alkyl groups which are optionally partially or totally halogenated.

[0055] According to certain embodiments, said at least one fluoropolymer is a PVDF.

[0056] According to certain embodiments, said at least one fluoropolymer is a P(VDF-TrFE), a P(VDF-TrFE-CTFE), a P(VDF-TrFE-CFE), or a mixture thereof.

[0057] According to certain embodiments, said at least one fluoropolymer is a P(VDF-TFE), a P(VDF-HFP), or a mixture thereof.

[0058] According to certain embodiments, said at least one fluoropolymer has a weight average molar mass greater than or equal to 100,000 g / mol, and more preferably greater than or equal to 200,000 g / mol.

[0059] The invention relates, according to a second aspect, to a method for treating a substrate with a fluoropolymer bonding primer comprising the steps of: i) depositing a reactive composition according to the invention on the surface of the substrate to be treated; ii) removing the solvent possibly present in the composition deposited in step i) on the surface of the substrate to be treated; iii) crosslinking at least a portion of said at least one PG polymer on the surface of the substrate so as to obtain a substrate covered with a layer comprising the at least partly crosslinked PG polymer; iv) optionally, annealing after step iii), preferably at a temperature of between 100°C and 150°C; and v) recovering the substrate coated with a layer of primer comprising the crosslinked PG polymer.

[0060] According to some embodiments, the crosslinking is carried out by electromagnetic irradiation or by electron beam.

[0061] According to certain embodiments, the crosslinking is carried out by heating, preferably at a temperature less than or equal to 150°C. According to certain embodiments, the thickness of the primer layer comprising the crosslinked PG polymer is less than or equal to 500 nm, preferably less than or equal to 250 nm, and more preferably less than or equal to 100 nm.

[0062] According to certain embodiments, the recovery of the substrate coated with a layer comprising the crosslinked PG polymer comprises a washing step using at least one solvent for said at least one PG polymer, in order to remove the fraction of said at least one PG polymer which has not crosslinked.

[0063] In some embodiments, the substrate is a surface of glass, silicon, quartz, polymer material, metal, nitride, or a mixed surface composed of several of these materials.

[0064] The invention relates, according to a third aspect, to a method for manufacturing a coating based on fluoropolymer(s) on a treated substrate comprising i) a method for treating a substrate as described above to form a substrate coated with a primer layer comprising a crosslinked PG polymer; ii) deposition of a composition comprising at least one fluoropolymer on said primer layer obtained in the preceding step; iii) where appropriate, removal of the solubilization solvent of said at least one fluoropolymer possibly present in said composition comprising said at least one fluoropolymer; and iv) recovery of the treated substrate coated with said at least one fluoropolymer.

[0065] The invention relates, according to a fourth aspect, to a composite C1 comprising a layer R1 based on at least one PG polymer crosslinked on a substrate, said at least one PG polymer being said at least one PG polymer according to the invention. The composite C1 can in particular be obtained by the method according to the second aspect. The composite C1 can in particular be used to adhere thereto (on the layer R1) at least one fluorinated polymer

[0066] The invention relates according to a fifth aspect to a composite C2 comprising a coating R2 comprising, being essentially constituted, or being constituted of at least one fluoropolymer, said coating R2 adhering to a composite C1 according to the fourth aspect. The composite C2 can in particular be obtained by the method according to the third aspect.

[0067] The invention finally relates, according to a sixth aspect, to a device comprising a composite C2 according to the fifth aspect. In this device, said coating R2 may be an electroactive coating, or an insulating and / or protective coating, or an electrode binder.

[0068] According to certain embodiments, the device is an optoelectronic device, a transistor, in particular a field effect transistor, a chip, a battery, a photovoltaic cell, a light-emitting diode, in particular an organic light-emitting diode, a sensor, an actuator, a transformer, a haptic device, a microelectromechanical system, or a detector.

[0069] Brief description of the figures

[0070] [Fig 1] schematically represents the 180° peel test carried out to evaluate the adhesion of a fluoropolymer-based film on a substrate partly covered with adhesion primer according to example 5.

[0071] [Fig. 2] is a graph representing the evolution of the residual MGH thickness (ordinates expressed in nanometers, nm) after exposure of the film to different doses of the electron beam according to example 7 (abscissas expressed in micro-Coulomb per square centimeter, pC / cm 2 ).

[0072] [Fig 3] is a graph representing the evolution of the residual MGH thickness (ordinates expressed in nanometers, nm) as a function of the thermocrosslinking temperature (abscissas expressed in degrees Celsius, °C).

[0073] Detailed description of the invention

[0074] Adhesion Precursor Polymer (PG)

[0075] PG polymer is a polymer suitable for improving the adhesion of a fluoropolymer to a substrate by being used as an adhesion precursor between the fluoropolymer and the substrate. This polymer includes units derived from the polymerization of methyl methacrylate (MMA) to allow good affinity between the PF fluoropolymer chains and the PG polymer chains.

[0076] Indeed, poly(methyl methacrylate) is known to have good affinity with fluorinated polymers, particularly with poly(vinylidene fluoride) with which it is even miscible in all proportions (Flory-Huggins parameter x between PVDF and PMMA negative).

[0077] Advantageously, the Flory-Huggins parameter x between the fluoropolymer PF, in particular PVDF, and the precursor PG is less than or equal to 0.5 and preferably less than or equal to 0. In the case where the polymer PG is a block polymer, it is one of the blocks, and according to certain embodiments all the blocks, which has / have a Flory-Huggins parameter x with the fluoropolymer PF, in particular PVDF, strictly less than 0.5, and preferably strictly less than 0.

[0078] The proportion of units derived from methyl methacrylate is generally at least 40% by weight, relative to the total weight of the PG precursor.

[0079] According to advantageous embodiments, the proportion of units derived from methyl methacrylate may be at least 45%, preferably at least 50%, preferably at least 55%, and still preferably at least 60%, by weight relative to the total weight of PG precursor.

[0080] According to particular embodiments, the proportion of units derived from methyl methacrylate may in particular be at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% by weight, relative to the total weight of PG polymer.

[0081] The PG precursor comprises at least one repeating unit comprising at least one reactive function. It may therefore comprise one or more repeating units, each comprising one or more reactive chemical functions, identical or different. To simplify the writing, the determinants "a" / "an" and "the" / "the" have been used before "reactive function", "repeating unit comprising a reactive function" and "PG polymer". They mean by default, and unless otherwise stated, "at least one" and "said at least one" reactive function, "at least one" and "said at least one" repeating unit comprising at least one reactive function, and "at least one" and "said at least one" PG polymer.

[0082] Said reactive function ensures a crosslinking reaction within the polymer. Said reactive function may in particular be a photo- and / or thermoreactive function. Certain reactive functions may be both photoreactive and thermoreactive.

[0083] According to certain embodiments, the reactive function of at least one repeating unit of the PG polymer is chosen from groups of the oxirane, aziridine or thiirane type. A repeating unit comprising an oxirane type group is for example the unit derived from glycidyl methacrylate.

[0084] According to certain embodiments, the reactive function of at least one repeating unit of the PG polymer is selected from a carbon-carbon double bond and a carbon-carbon triple bond.

[0085] According to certain embodiments, the PG polymer comprises at least one repeating unit other than that derived from methyl methacrylate and that(those) comprising at least one reactive function.

[0086] This other unit may be capable of grafting with the reactive function of PG. It may in particular be chosen from units resulting from the polymerization of non-(meth)acrylic silylated vinyl monomers, silylated styrenic monomers, acrylic acid, methacrylic acid, and alkyl esters of acrylic or methacrylic acid whose alkyl chain is substituted by at least one group chosen from: -SiHs, alkylsilane, oxysilane, phosphonate, phosphonic acid, alcohol, amino, thiol, thioester.

[0087] Advantageously, the repeating unit capable of grafting with the reactive function is chosen from units derived from the polymerization of acrylic acid, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate or 2-hydroxypropyl acrylate, methacrylic acid, and hydroxyalkyl methacrylates such as 2-hydroxyethyl methacrylate or 2-hydroxypropyl methacrylate. The other repeating unit capable of grafting with the reactive function may in particular be derived from 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate.

[0088] The PG polymer may also comprise one or more repeating units not comprising a reactive function or a group capable of grafting onto the reactive function. Such a repeating unit may in particular be chosen from vinylaromatic monomers such as styrene or substituted styrenes, in particular alpha-methylstyrene, tert-butylstyrene, ortho-, meta-, or para-methylstyrene, ortho-, meta- or para-ethylstyrene, o-methyl-p-isopropylstyrene, alkyl, cycloalkyl or aryl acrylates such as methyl, ethyl, propyl, butyl, ethylhexyl or phenyl acrylate, fluorinated acrylates, isobornyl acrylate, 4-tert-butylcyclohexyl acrylate, alkyl, cycloalkyl, alkenyl or aryl methacrylates such as methyl, ethyl, propyl, butyl, lauryl, cyclohexyl, allyl, phenyl or naphthyl, and fluorinated methacrylates such as 2,2,2-trifluoroethyl methacrylate.

[0089] According to preferred embodiments, the PG polymer is a linear polymer.

[0090] According to some embodiments, the PG polymer is a gradient or random copolymer.

[0091] The term "statistical copolymer" means a copolymer resulting from the polymerization of at least two monomers in which the distribution of the monomer units along the chain follows a statistical law, for example of the Bernoullian type (Markov zero order) or Markovian of the first or second order.

[0092] The term "gradient copolymer" is understood to mean a copolymer resulting from the polymerization of at least two monomers generally obtained by living or pseudo-living polymerization, such as the NMP polymerization presented below. Thanks to these polymerization modes, the polymer chains grow simultaneously and therefore incorporate the same ratios of comonomers at each instant. The distribution of the comonomers in the polymer chains therefore depends on the evolution, during the synthesis, of the relative concentrations of the comonomers.

[0093] The PG polymer may include:

[0094] - from 5% to 30% by weight of one or more repeating units each comprising at least one reactive function, relative to the weight of the PG polymer, it being understood that if the PG polymer comprises several repeating units, it is their entire weight which is taken into account; from 40% to 95% by weight of repeating unit resulting from the polymerization of methyl methacrylate, relative to the weight of the PG polymer.

[0095] The PG polymer may in particular be essentially constituted, or be constituted: - from 5% to 30% by weight of one or more repeating units each comprising at least one reactive function, relative to the weight of the PG polymer, it being understood that if the PG polymer comprises several repeating units, it is their entire weight which is taken into account; from 40% to 95% by weight of repeating unit resulting from the polymerization of methyl methacrylate, relative to the weight of the PG polymer;

[0096] - from 0% to 30% by weight of another repeating unit capable of grafting with said at least one reactive function, relative to the weight of the PG polymer;

[0097] - from 0% to less than 40% by weight of another repeating unit having neither a reactive function nor a group capable of grafting onto the reactive function, relative to the weight of the PG polymer.

[0098] The PG polymer may in particular be essentially made up of, or be made up of:

[0099] - from 10% to 25% by weight of one or more repeating units each comprising at least one reactive function, relative to the weight of the PG polymer, it being understood that if the PG polymer comprises several repeating units, it is their entire weight which is taken into account; from 50% to 75% by weight of repeating unit resulting from the polymerization of methyl methacrylate, relative to the weight of the PG polymer;

[0100] - from 1% to 25% by weight of another repeating unit capable of grafting with said at least one reactive function, relative to the weight of the PG polymer;

[0101] - from 0% to 30% by weight of another repeating unit having neither a reactive function nor a group capable of grafting onto the reactive function, relative to the weight of the PG polymer.

[0102] For example, the PG polymer may consist essentially of, or be made up of:

[0103] - from 10% to 25% by weight of a repeating unit derived from glycidyl methacrylate, from 50% to 75% by weight of a repeating unit derived from the polymerization of methyl methacrylate, relative to the weight of the PG polymer, and

[0104] - from 1% to 25% by weight of a repeating unit derived from 2-hydroxyethyl methacrylate; relative to the weight of PG polymer. The PG polymer may in particular consist essentially of, or consist of:

[0105] - from 10% to 25% by weight of one or more repeating units each comprising at least one reactive function, relative to the weight of the PG polymer, it being understood that if the PG polymer comprises several repeating units, it is their entire weight which is taken into account; from 50% to 75% by weight of repeating unit resulting from the polymerization of methyl methacrylate, relative to the weight of the PG polymer;

[0106] - from 5% to 20% by weight of another repeating unit capable of grafting with said at least one reactive function, relative to the weight of PG polymer;

[0107] - from 5% to 25% by weight of another repeating unit having neither a reactive function nor a group capable of grafting onto the reactive function, relative to the weight of PG polymer.

[0108] For example, the PG polymer may in particular be essentially made up of, or be made up of:

[0109] - from 10% to 25% by weight of a repeating unit derived from glycidyl methacrylate, from 50% to 75% by weight of a repeating unit derived from the polymerization of methyl methacrylate,

[0110] - from 5% to 20% by weight of repeating unit derived from 2-hydroxyethyl methacrylate, and

[0111] - from 5% to 25% by weight of repeating unit derived from tert-butyl methacrylate; relative to the weight of PG polymer.

[0112] According to certain embodiments, the PG polymer is a block copolymer. It may in particular comprise at least one block A comprising a repeating unit derived from methyl methacrylate and at least one block B comprising a repeating unit comprising a reactive function.

[0113] Advantageously, the block(s) A do not comprise a repeating unit comprising at least one reactive function. According to certain embodiments, the block(s) A have a Flory-Huggins parameter x with the fluoropolymer PF less than or equal to 0.5, and preferably less than or equal to 0.

[0114] Advantageously, the block(s) B do not comprise a repeating unit derived from methyl methacrylate. According to certain embodiments, the block(s) B have a Flory-Huggins parameter x with the fluoropolymer PF strictly greater than 0.5. In preferred embodiments, the polymer PG may be a block polymer of type P(AbB) where A and B are the blocks as described above.

[0115] The PG block polymer may comprise:

[0116] - from 0.5% to 20% by weight of said at least one repeating unit comprising at least one reactive function, relative to the weight of the PG polymer,

[0117] - from 60% to 99.5% by weight of repeating unit derived from methyl methacrylate, relative to the weight of the PG polymer.

[0118] The PG block polymer may in particular be essentially made up of, or be made up of:

[0119] - from 0.5% to 20% by weight of said at least one repeating unit comprising at least one reactive function, relative to the weight of the PG polymer,

[0120] - from 60% to 99.5% by weight of repeating unit derived from methyl methacrylate, relative to the weight of the PG polymer,

[0121] - from 0% to 20% by weight of another repeating unit capable of grafting with said at least one reactive function, relative to the weight of PG polymer;

[0122] - from 0% to 30% by weight of another repeating unit having neither a reactive function nor a group capable of grafting onto the reactive function, relative to the weight of PG polymer.

[0123] The PG block polymer may in particular be essentially made up of, or be made up of:

[0124] - from 0.5% to 15% by weight of said at least one repeating unit comprising at least one reactive function, relative to the weight of the PG polymer,

[0125] - from 60% to 99.5% by weight of repeating unit derived from methyl methacrylate, relative to the weight of the PG polymer,

[0126] - from 5% to 20% by weight of another repeating unit capable of grafting with said at least one reactive function, relative to the weight of PG polymer;

[0127] - from 0% to 30% by weight of another repeating unit having neither a reactive function nor a group capable of grafting onto the reactive function, relative to the weight of PG polymer.

[0128] For example, the PG block polymer may in particular be a P(AbB) type block polymer in which block A is essentially constituted, or constituted, of repeating units derived from methyl methacrylate (MMA) and block B is essentially constituted, or constituted, of repeating units derived from 2-hydroxyethyl acrylate (HEA) and glycidyl methacrylate (GMA). The proportion of MMA / HEA / GMA in the block polymer may be such that MMA represents 60% to 99.5% by weight, HEA represents from 0.5% to 15% by weight and GMA represents from 0.5% to 15% by weight, relative to the weight of the polymer.

[0129] According to some embodiments, the PG polymer has a number average molar mass of 1,000 g / mol to 150,000 g / mol, preferably 1,500 g / mol to 100,000 g / mol, and more preferably 2,000 g / mol to 50,000 g / mol. The molecular weight distribution can be estimated by SEC with polystyrene standards.

[0130] The PG precursor can be implemented by any polymerization technique known to those skilled in the art. It is generally manufactured by radical polymerization and preferably by controlled radical polymerization. Among the controlled radical polymerization techniques, we can cite: NMP ("Nitroxide Mediated Polymerization"), RAFT ("Reversible Addition and Fragmentation Transfer"), ATRP ("Atom Transfer Radical Polymerization"), INIFERTER ("Initiator-Transfer-Termination"), and RITP ("Reverse Iodine Transfer Polymerization").

[0131] Reactive composition comprising the adhesion precursor (PG)

[0132] The reactive composition comprises at least one, i.e. one or more, PG adhesion precursors.

[0133] The PG precursor can be dissolved in a solvent or mixture of solvents. By "solution" is meant a homogeneous dispersion of the constituents in the solvent, at the molecular level. The term solution is used here in contrast to a suspension of polymer particles in a liquid vehicle, and in contrast to a polymer emulsion or latex.

[0134] Preferably, the solvent is chosen from: dimethylformamide; N-methyl-2-pyrrolidone; dimethylacetamide; dimethylsulfoxide; γ-butyrolactone; ketones, in particular acetone, methyl ethyl ketone (or butan-2-one), methyl isobutyl ketone, cyclopentanone, cyclohexanone, diisobutyl ketone; furans, in particular tetrahydrofuran; esters, in particular methyl acetate, ethyl acetate, propyl acetate, butyl acetate, propylene glycol methyl ether acetate, glyceryl triacetate, diethylene glycol monobutyl ether acetate, and ethyl acetoacetate; carbonates, in particular dimethylcarbonate and propylene carbonate; and phosphates, in particular trimethylphosphate and triethylphosphate. Mixtures of these compounds can also be used.

[0135] In some embodiments, the solvent may be N-methyl-2-pyrrolidone.

[0136] In some embodiments, the solvent may be selected from the list consisting of: dimethylformamide, N-methyl-2-pyrrolidone, dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, diisobutyl ketone, tetrahydrofuran, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, propylene glycol methyl ether acetate, glyceryl triacetate, diethylene glycol monobutyl ether acetate, ethyl acetoacetate, dimethyl carbonate, propylene carbonate, trimethylphosphate, triethylphosphate. Mixtures of these compounds may also be used.

[0137] The reactive composition in solution preferably comprises from 0.1 to 60%, more preferably from 0.5 to 30%, more preferably from 1 to 20%, and more preferably from 3 to 15% by weight of PG polymer relative to the total weight of composition.

[0138] According to certain variants, the reactive composition may comprise a photoinitiator and optionally a synergistic coinitiator such as derivatives comprising at least one amine or silyl type function. According to other variants, the reactive composition may comprise a thermal initiator.

[0139] In the embodiments where the reactive function of the PG polymer is chosen from groups of the oxirane, aziridine or thiirane type, then:

[0140] - a photoinitiator may be chosen from acid-generating photoinitiators (PAG), preferably from onium salts, in particular sulfonium, iodonium and pyridinium salts, ferrocene derivatives, nitrobenzyl ester type derivatives, sulfones, aryl phosphates, derivatives comprising N-hydroxysuccinimide sulfonate functions, sulfonic acid esters; and base-generating photoinitiators (PBG), preferably from derivatives comprising functions of O-acyloxime, benzoyloxycarnoyl or o-nitrobensoyloxycarbonyl type, or formamide;

[0141] - a thermal initiator may be chosen from chemical derivatives for generating a thermally activated acid proton, such as ammonium salts such as triflate, ammonium trifluoroacetate or ammonium trifluoromethanesulfonate, pyridinium salts such as pyridinium paratoluenesulfonate, phosphoric or sulfuric or sulfonic acids such as p-toluenesulfonic acid 4-nitrobenzyloate, or onium salts such as iodonium salts such as bis-4-tert-butylphenyliodonium hexafluorophosphate or phosphonium salts, or imidazolium salts. In the embodiments where the reactive function of the PG polymer is chosen from a carbon-carbon double bond and a carbon-carbon triple bond, then:

[0142] - a photoinitiator may be chosen from compounds having a function of the aryl-ketone type, α-amino ketones, benzylic acetals, xanthones or thioxanthones, phosphine oxides, and titanocene-type derivatives;

[0143] - a thermal initiator, the thermal initiator being a radical initiator chosen from organic peroxide type derivatives such as benzoyl peroxide, or derivatives comprising an azo type chemical function such as azobisisobutyronitrile (AIBN), or even alkyl halide type derivatives.

[0144] The photoinitiator and optionally its synergistic coinitiator, the photoinitiator, or the thermal initiator are advantageously present in the reactive composition with a content less than or equal to 30% by weight, and preferably less than or equal to 20% by weight, and more preferably with a content less than or equal to 15% by weight relative to the weight of PG polymer in the composition.

[0145] The photoinitiator and optionally its synergistic coinitiator, the photoinitiator, or the thermal initiator are advantageously present in the reactive composition with a content greater than or equal to 1% by weight, and more preferably greater than or equal to 3% by weight.

[0146] The reactive composition may comprise a compound M not comprising said reactive function and comprising a function chosen from: nitroxy, - SiHs, alkylsilane, oxysilane, phosphonate, phosphonic acid, alcohol, amino, thiol, and thioester.

[0147] The reactive composition may in particular comprise a compound M not comprising said reactive function and comprising a function chosen from: SiHs, alkylsilane, oxysilane, phosphonate, phosphonic acid, alcohol, amino, thiol, and thioester.

[0148] Such a compound M can act as a co-crosslinker with the PG polymer and be introduced into the composition in a PG:M mass ratio of 2:1 to 99:1, and preferably of 5:1 to 95:1.

[0149] The reactive composition may optionally comprise one or more other additives, in particular chosen from surface tension modifying agents, rheology modifying agents, ageing resistance modifying agents, pigments or dyes, fillers (including nanofillers). The other additive(s) generally represent less than 10%, preferably less than 5%, and even more preferably less than 1% by weight relative to the weight of PG precursor.

[0150] According to certain embodiments, the composition is essentially constituted, or constituted, of at least one PG precursor, of an initiator chosen from: a photoinitiator optionally having a synergistic coinitiator, a photoinitiator, or a thermal initiator, optionally of a compound M, and optionally also of other additives.

[0151] According to certain embodiments, the composition is a solution essentially consisting of, or consisting of, at least one PG precursor, an initiator chosen from: a photoinitiator optionally having a synergistic coinitiator, a photoinitiator, or a thermal initiator, a solvent or a mixture of miscible solvents, optionally a compound M, and optionally also other additives. The solution preferably has a non-volatile solids content of 0.1 to 60%, preferably 0.5 to 30%, more preferably 1 to 20%.

[0152] Fluoropolymer (PF)

[0153] The PF polymer is a fluoropolymer, that is to say it comprises repeating units (or units, or structural units, or motifs) which are derived from (that is to say which are obtained by polymerization of) fluoromonomers.

[0154] The PF polymer may in particular be a polymer comprising a vinylidene fluoride (VDF) repeating unit.

[0155] The PF polymer may in particular be a polymer based on the repeating unit derived from VDF, i.e. comprising at least 50% by mole of repeating unit derived from VDF, relative to the total sum of moles of repeating units constituting the PF polymer.

[0156] In some embodiments, the PF polymer is a PVDF homopolymer, i.e., is made up of the repeating unit derived from VDF.

[0157] In certain embodiments, the PF polymer is a copolymer (in the broad sense), that is to say it comprises units derived from at least one other monomer X than VDF.

[0158] A single monomer X can be used, or several different monomers X, depending on the case.

[0159] In some embodiments, monomer X may be of formula CXiX2=CX3X4, wherein each group Xi, X2, X3 and X4 is independently selected from H, Cl, F, Br, I and C1-C3 (preferably C1-C2) alkyl groups, which are optionally partially or fully halogenated - wherein monomer X is different from VDF (i.e., if X1 and X2 are H, at least one of X3 and X4 is not F; and if Xi and X2 are F, at least one of X3 and X4 is not H).

[0160] In some embodiments, each group X1, X2, X3 and X4 independently represents an H, F, Cl, I or Br atom, or a methyl group optionally comprising one or more substituents selected from F, Cl, I and Br.

[0161] In some embodiments, each group X1, X2, X3 and X4 independently represents an H, F, Cl, I or Br atom.

[0162] In some embodiments, only one of X1, X2, X3 and X4 represents a Cl or I or Br atom, and the others of the groups X1, X2, X3 and X4 independently represent: an H or F atom or a C1-C3 alkyl group optionally comprising one or more fluorine substituents; preferably, an H or F atom or a C1-C2 alkyl group optionally comprising one or more fluorine substituents; and more preferably, an H or F atom or a methyl group optionally comprising one or more fluorine substituents.

[0163] Examples of monomers X are: vinyl fluoride (VF), trifluoroethylene (TrFE), tetrafluoroethylene (TFE), hexafluoropropene (HFP), trifluoropropenes and in particular 3,3,3-trifluoropropene, tetrafluoropropenes and in particular 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene (in cis or preferably trans form), hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropenes and in particular 1,1,3,3,3-pentafluoropropene or 1,2,3,3,3-pentafluoropropene, perfluoroalkylvinylethers and in particular those of general formula Rf-O-CF=CF2, Rf being an alkyl group, preferably C1 to C4 (preferred examples being perfluoropropylvinylether or PPVE and perfluoromethylvinylether or PMVE).

[0164] In some embodiments, the monomer X comprises a chlorine or bromine atom. It may in particular be chosen from bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoroethylene and chlorotrifluoropropene. Chlorofluoroethylene may denote either 1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene. The isomer 1-chloro-1-fluoroethylene (CFE) is preferred. Chlorotrifluoropropene is preferably 1-chloro-3,3,3-trifluoropropene (in cis or trans form, preferably trans) or 2-chloro-3,3,3-trifluoropropene.

[0165] In certain preferred embodiments, the PF polymer comprises units derived from VDF and HFP, or is a P(VDF-HFP) polymer consisting of units derived from VDF and HFP. Such a PF polymer is particularly useful for the manufacture of planarization or passivation layers of electronic devices.

[0166] The molar proportion of repeating units derived from HFP is preferably from 2 to 50%, in particular from 5 to 40%, in moles relative to the total number of moles of repeating units derived from VDF and HFP. The copolymer P(VDF-HFP) may in particular be as described in documents WO 01 / 32726 and US 6,586,547 to which express reference is made.

[0167] In certain preferred embodiments, the PF polymer comprises units derived from VDF and TFE, or is a P(VDF-TFE) polymer consisting of units derived from VDF and TFE. This polymer is generally used for its piezoelectric properties.

[0168] The molar proportion of repeating units derived from TFE is preferably from 8% to 30%, preferably from 15% to 28%, more preferably from 18% to 25%, and extremely preferably from 20% to 22%, relative to the total number of moles of the units derived from VDF and TFE.

[0169] In some embodiments, the PF polymer comprises units derived from VDF and: CFE, or CTFE, or TrFE.

[0170] In certain preferred embodiments, the PF polymer comprises units derived from VDF and TrFE. Such a PF polymer is generally useful for the fabrication of electroactive layers.

[0171] According to certain advantageous embodiments, the PF polymer may in particular be a P(VDF-TrFE) polymer, i.e. consisting of units derived from VDF and TrFE. These polymers are generally used for their piezoelectric, pyroelectric and ferroelectric properties, for example in sensors, energy harvesting devices, actuators, loudspeakers or ferroelectric memories.

[0172] The molar proportion of repeating units derived from TrFE is preferably from 15% to 50%, preferably from 17% to 35%, and more preferably from 18% to 32.5%, relative to the total number of moles of units derived from VDF and TrFE. Such polymers are ferroelectrics. The term "ferroelectric" is understood to mean an electroactive polymer characterized by a hysteresis cycle of the electric displacement-applied electric field curve. Its coercive field at 25°C is typically lower in absolute value than 60 V / pm and higher than 40 V / pm. Its remanent polarization at 25°C is quite high, and can typically reach a value higher than 50 mC / m 2 The Curie temperature corresponds to a ferroelectric -> paraelectric (FE -> PE) crystal structure transition, called the Curie transition.

[0173] The molar proportion of repeating units derived from TrFE may in particular be from 15% to 18%, or from 18% to 22.5%, or from 22.5% to 27.5%. According to particular embodiments, the molar proportion of repeating units derived from TrFE is from 18.0% to 22.5%, relative to the total number of moles of the units derived from VDF and TrFE.

[0174] The molar proportion of repeat units derived from TrFE may also be from 27.5% to 32.5%, or from 32.5% to 37.5%, or from 37.5% to 42.5%, or from 42.5% to 47.5%, or from 47.5% to 50%, relative to the total number of moles of units derived from VDF and TrFE. According to certain advantageous embodiments, the polymer PF may comprise units derived from VDF, TrFE and another monomer X as defined above, different from VDF and TrFE, or else be a polymer P(VDF-TrFE-X) consisting of units derived from VDF, TrFE and another monomer X as defined above, different from VDF and TrFE. In this case, preferably, the other monomer X is chosen from TFE, HFP, trifluoropropenes and in particular 3,3,3-trifluoropropene, tetrafluoropropenes and in particular 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene (in cis or preferably trans form), bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoroethylene and chlorotrifluoropropene.

[0175] CTFE or CFE are particularly preferred. Indeed, P(VDF-TrFE-CTFE) and P(VDF-TrFE-CFE) terpolymers are known to have a high dielectric constant (“high-k”) as well as for their electrostrictive and electrocaloric properties and are used for example as “High-k” dielectric in organic thin film transistors (OTFT), actuators and electrocaloric devices.

[0176] The molar proportion of units derived from TrFE is preferably from 10% to 60%, more preferably from 15% to 55% and more preferably from 20% to 50%, relative to the total number of moles of units derived from VDF and TrFE.

[0177] The molar proportion of units derived from another monomer X, in addition to VDF and TrFE (the monomer X being in particular CTFE or CFE), relative to the number of moles of the units constituting the polymer PF, is preferably from 0.05% to 15%, and more preferably from 2% to 12%.

[0178] According to certain embodiments, X is CTFE or CFE, the molar proportion of X relative to the number of moles of the units constituting the PF polymer being from 4% to 10%. The P(VDF-TrFE-CFE) and P(VDF-TrFE-CTFE) having the aforementioned proportions of TrFE and CFE or CTFE are relaxor ferroelectrics. The term "relaxor ferroelectric" is understood to mean an electroactive polymer characterized by a relaxor-ferroelectric (RFE) paraelectric (PE) crystalline transition over a wide temperature range. At this transition, a broad peak of dielectric permittivity is observed, the temperature of this maximum depending on the frequency of the applied electric field: the lower the frequency of the electric field, the more the maximum of dielectric permittivity is shifted towards low temperatures.At the (RFE)->(PE) transition temperatures or slightly higher, the application of an electric field allows the generation and alignment of nanopolar regions, inducing an entropy variation, and thus a significant electrocaloric effect over a wide temperature range. Relaxant ferroelectric polymers are characterized at 25°C, and at a frequency of about 1 Hz by a hysteresis cycle of the "electric displacement" curve as a function of the "applied electric field" much finer than the hysteresis cycle of a ferroelectric polymer. They typically have a coercive field less than or equal in absolute value to 45 V / pm and a remanent polarization less than or equal to 40 mC / m. 2 .

[0179] In the embodiments where X is CTFE or CFE, the molar proportion of units derived from CTFE or CFE may in particular be from 0.05% to 0.5%, or from 0.5% to 2%, or from 2% to 3%, or from 3% to 4%, or from 10% to 12%, or from 12% to 15%, relative to the number of moles of the units constituting the PF polymer.

[0180] The molar composition of units in fluoropolymers can be determined by various means such as infrared spectroscopy or RAMAN spectroscopy. Classical methods of elemental analysis in carbon, fluorine and chlorine or bromine or iodine, such as X-ray fluorescence spectroscopy, allow the mass composition of polymers to be calculated unambiguously, from which the molar composition is deduced.

[0181] Multi-nucleus NMR techniques, including proton (1 H) and fluorine (19 F), can also be used by analyzing a solution of the polymer in a suitable deuterated solvent. The NMR spectrum is recorded on an FT-NMR spectrometer equipped with a multi-nuclear probe. The specific signals given by the different monomers are then identified in the spectra produced according to one or the other nucleus. Thus, for example, the unit derived from TrFE gives a specific signal in proton NMR characteristic of the CFH group (at approximately 5 - 7 ppm, when the solvent is pyridine for example). The same is true for the CH2 groups of VDF (massive between 2 - 4 ppm, when the solvent is pyridine for example). The relative integration of the two signals gives the relative abundance of the two monomers, i.e. the VDF / TrFE molar ratio.

[0182] Similarly, the CF3 group, for example, gives characteristic and well-isolated signals in fluorine NMR. The combination of the relative integrations of the different signals obtained in proton NMR and fluorine NMR leads to a system of equations whose resolution leads to obtaining the molar concentrations of the units resulting from the different monomers.

[0183] Finally, it is possible to combine elemental analysis, for example for heteroatoms such as chlorine, bromine or iodine, and NMR analysis. Thus, the content of CTFE-derived units in a P(VDF-TrFE-CTFE) terpolymer, for example, can be determined by measuring the chlorine content by elemental analysis.

[0184] The skilled person thus has a range of methods or combinations of methods enabling him to determine the composition of fluoropolymers unambiguously and with the necessary precision. The PF polymer is preferably statistical. The PF polymer is preferably linear.

[0185] PF polymer can be produced using any known process, such as emulsion polymerization, suspension polymerization and solution polymerization.

[0186] When the fluoropolymer comprises units derived from VDF and / or TrFE as well as another monomer X as described above, it is preferable to use the method described in document WO 2010 / 116105. This method makes it possible to obtain polymers of high molecular weight and suitable structuring.

[0187] In brief, the preferred method includes the following steps:

[0188] - loading an initial mixture containing only VDF and / or TrFE (without the other monomer X) into a stirred autoclave containing water;

[0189] - heating the autoclave to a predetermined temperature, close to the polymerization temperature;

[0190] - injecting a radical polymerization initiator mixed with water into the autoclave, in order to reach a pressure in the autoclave which is preferably at least 80 bars, so as to form a suspension of the VDF and / or TrFE monomers in water;

[0191] - the injection of a second mixture of VDF and / or TrFE and X into the autoclave;

[0192] - as soon as the polymerization reaction starts, the continuous injection of said second mixture into the autoclave reactor, in order to maintain the pressure at an essentially constant level, preferably at least 80 bars.

[0193] The radical polymerization initiator may be, in particular, an organic peroxide of the peroxydicarbonate type. It is generally used in an amount of 0.1 to 10 g per kilogram of the total monomer loading. Preferably, the amount used is 0.5 to 5 g / kg.

[0194] The initial mixture advantageously comprises only VDF and / or TrFE in a proportion equal to that of the desired final polymer.

[0195] The second mixture advantageously has a composition which is adjusted so that the total composition of monomers introduced into the autoclave, including the initial mixture and the second mixture, is equal to or approximately equal to the composition of the desired final polymer.

[0196] The weight ratio between the second mixture and the initial mixture is preferably from 0.5 to 2, more preferably from 0.8 to 1.6.

[0197] Implementing this process with an initial mixture and a second mixture makes the process independent of the reaction start-up phase, which is often unpredictable. The polymers thus obtained are in the form of a powder, without a crust or skin.

[0198] The pressure in the autoclave reactor is preferably 80 to 110 bars, and the temperature is maintained at a level preferably of 40°C to 60°C.

[0199] The second mixture can be injected continuously into the autoclave. It can be compressed before being injected into the autoclave, for example by using one or two successive compressors, generally at a pressure higher than the pressure in the autoclave.

[0200] After synthesis, the polymer can be washed and dried.

[0201] The weight average molar mass Mw of the PF polymer is preferably at least 100,000 g. mol' 1 , preferably at least 200,000 g. mol' 1and more preferably at least 300,000 g. mol' 1 or at least 400,000 g. mol' 1 . It can be adjusted by changing some process parameters, such as the temperature in the reactor, or by adding a transfer agent. The molecular weight distribution can be estimated by SEC (size exclusion chromatography) with dimethylformamide (DMF) as eluent, with a set of 3 columns of increasing porosity. The stationary phase is a styrene-DVB gel. The detection method is based on a measurement of the refractive index, and the calibration is carried out with polystyrene standards. The sample is dissolved at 0.5 g / L in DMF and filtered through a 0.45 µm nylon filter.

[0202] Composition based on fluorinated polymer(s)

[0203] The composition comprises at least one, i.e. one or more, fluoropolymer PF.

[0204] The determinants "a" and "the" have been used before "fluoropolymer PF". They mean by default, and unless otherwise stated, "at least one" and "said at least one" fluoropolymer PF. They include, according to particular embodiments, cases where the composition comprises only one type of fluoropolymer.

[0205] The PF polymer can be dissolved in a solvent or a mixture of solvents. By "solution" is meant a homogeneous dispersion of the constituents in the solvent, at the molecular level. The term solution is used here in contrast to a suspension of polymer particles in a liquid vehicle, and in contrast to a polymer emulsion or latex.

[0206] Preferably, the solvent is chosen from: dimethylformamide; N-methyl-2-pyrrolidone; dimethylacetamide; dimethylsulfoxide; γ-butyrolactone; ketones, in particular acetone, methyl ethyl ketone (or butan-2-one), methyl isobutyl ketone, cyclopentanone, cyclohexanone, diisobutyl ketone; furans, in particular tetrahydrofuran; esters, in particular methyl acetate, ethyl acetate, propyl acetate, butyl acetate, propylene glycol methyl ether acetate, glyceryl triacetate, diethylene glycol monobutyl ether acetate, and ethyl acetoacetate; carbonates, in particular dimethylcarbonate and propylene carbonate; and phosphates, in particular trimethylphosphate and triethylphosphate. Mixtures of these compounds can also be used.

[0207] In some embodiments, the solvent may be N-methyl-2-pyrrolidone.

[0208] In some embodiments, the solvent may be selected from the list consisting of: dimethylformamide, N-methyl-2-pyrrolidone, dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, diisobutyl ketone, tetrahydrofuran, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, propylene glycol methyl ether acetate, glyceryl triacetate, diethylene glycol monobutyl ether acetate, ethyl acetoacetate, dimethyl carbonate, propylene carbonate, trimethylphosphate, triethylphosphate. Mixtures of these compounds may also be used.

[0209] The composition, in solution form, preferably comprises from 0.1 to 60% by weight, preferably from 0.5 to 30% by weight, more preferably from 1 to 20% by weight, and extremely preferably from 3 to 15% by weight of non-volatile dry matter.

[0210] The composition may optionally comprise one or more additives, in particular chosen from surface tension modifying agents, rheology modifying agents, ageing resistance modifying agents, pigments or dyes, fillers (including nanofillers). The additive(s) generally represent less than 10%, preferably less than 5%, and even more preferably less than 1% by weight relative to the weight of PF polymer.

[0211] According to certain embodiments, the composition consists essentially of, or consists of, at least one fluoropolymer. The composition may optionally comprise one or more additives.

[0212] According to some embodiments, the composition consists essentially of, or consists of, at least one fluoropolymer and one or more miscible solvents. The composition may optionally comprise one or more additives.

[0213] According to certain embodiments, the composition based on PG precursor(s), respectively the composition based on fluorinated polymer(s), are solutions in which the PG precursor(s), respectively the fluorinated polymer(s), are dispersed in the same solvent or the same mixture of solvents.

[0214] Method for treating a substrate The method for treating a substrate with a fluoropolymer primer comprising the steps of: i) depositing a reactive composition as defined in the invention on the surface of the substrate to be treated; ii) removing the solvent possibly present in the composition deposited in step i) on the surface of the substrate to be treated; iii) crosslinking at least a portion of the PG polymer on the surface of the substrate so as to obtain a substrate covered with a layer comprising the at least partly crosslinked PG polymer; iv) optionally, annealing after step iii), preferably at a temperature between 100°C and 150°C; and v) recovering the substrate coated with a layer of primer comprising the crosslinked PG polymer.

[0215] The substrate on which the composition based on PG adhesion precursor(s) can be deposited may be an electrical conductor, an electrical insulator or a semiconductor. The substrate may in particular be a surface of glass, or silicon, or quartz, or polymer material (in particular polyethylene terephthalate, polyethylene naphthalate, PEDOT-PSS), or metal, or a mixed surface composed of several different materials.

[0216] According to certain preferred variants, the substrate is or comprises a metallic surface M, comprising gold, silver, chromium, aluminum, copper, lithium, zinc, nickel, cobalt, manganese, and their alloys. According to certain preferred variants, the substrate is or comprises an oxidized surface, with functions of the -M-OH type, M representing a metallic atom which may in particular be gold, silver, chromium, aluminum, copper, lithium, zinc, nickel, cobalt, manganese, and their alloys.

[0217] According to certain preferred variants, the substrate is or comprises a surface comprising silanol -SiOH functions, and in particular a glass or silicon surface.

[0218] The application of the composition to form a precursor layer to be crosslinked may include spreading by discrete or continuous means. The deposition may be carried out in particular by spin-coating, by spray coating, by coating in particular with a bar or film puller, by coating with a slotted head, by immersion, by dip coating, by roll-to-roll printing, by screen printing, by flexographic printing, by lithographic printing or by inkjet printing, by electrospinning, or by extrusion.

[0219] When the composition is applied in solution form, the solvent must be evaporated after deposition. Evaporation can be carried out at room temperature (23°C) and / or by heating to a temperature preferably ranging from 50 to 150°C. The layer may be subjected to ventilation to facilitate evaporation. The evaporation time may be, for example, 1 minute to 1 hour. In particular, the evaporation time may be less than 10 minutes.

[0220] Crosslinking can be carried out by electromagnetic irradiation or by electron beam, or by heating, preferably at a temperature less than or equal to 150°C. The duration of crosslinking can in particular be less than 10 minutes, and advantageously less than 5 minutes.

[0221] One or more annealing steps may be carried out after the formation of the dry layer of adhesion primer (PG precursor having crosslinked). Annealing is advantageously carried out at a temperature less than or equal to 150°C. The annealing time may in particular be less than 10 minutes, and advantageously less than 5 minutes.

[0222] Once at least a fraction of the PG precursor has been crosslinked to the surface of the substrate, washing using at least one solvent of said at least one PG polymer can be carried out in order to remove the fraction of said at least one PG polymer which has not been crosslinked.

[0223] The primer layer on the surface of the substrate is generally very thin. It can have a thickness less than or equal to 500 nm, preferably less than or equal to 250 nm, and preferably less than or equal to 100 nm.

[0224] The composite formed by the stacking of the substrate and the thin layer of primer constitutes a treated substrate capable of exhibiting good adhesion properties with a fluoropolymer.

[0225] Method of manufacturing a coating of fluoropolymer(s) on a treated substrate

[0226] The application of the composition based on fluoropolymer(s) to form a coating on the substrate treated with the primer layer may comprise spreading by discrete or continuous means. The deposition may be carried out in particular by spin-coating, by spray coating, by coating in particular with a bar or film puller, by coating with a slotted head, by immersion, by dip coating, by roll-to-roll printing, by screen printing, by flexographic printing, by lithographic printing or by inkjet printing, by electrospinning, or by extrusion.

[0227] According to particular embodiments, the deposition of a composition not comprising a solvent can be carried out by extrusion.

[0228] According to particular embodiments, the deposition of a composition in the form of a solution can be carried out by coating, in particular with a bar or a film puller ("bar coating") or by screen printing.

[0229] When the composition is applied in solution form, the solvent must be evaporated after deposition. Evaporation may be carried out at room temperature (23°C) and / or by heating to a temperature preferably ranging from 50 to 150°C. The layer may be subjected to ventilation to facilitate evaporation. The evaporation time may be, for example, from 1 minute to 24 hours, preferably from 2 minutes to 5 hours, and more preferably from 3 minutes to 2 hours. The evaporation time may in particular be less than 1 hour. The evaporation time may in particular be 30 minutes or less, or 20 minutes or less, or 15 minutes or less, or 10 minutes or less.

[0230] The dry coating of fluorinated polymer(s) formed may have a thickness of 1 μm to a thickness of the order of a millimeter. Such thicknesses may be obtained by deposition of a single layer according to one of the aforementioned methods or by deposition of successive layers produced by iteration of at least one of the aforementioned methods.

[0231] According to certain embodiments, the coating has a thickness of 1 μm to 100 μm. The coating may in particular have a thickness of 1 μm to 10 μm, or of 10 μm to 50 μm, or of 50 μm to 100 μm. The coating may in particular be in the form of a film of substantially constant thickness.

[0232] According to certain embodiments, the coating has a thickness of 100 μm to 1000 μm. The coating may in particular have a thickness of 100 μm to 250 μm, or of 250 μm to 500 μm, or of 500 μm to 1000 μm. The coating may in particular have a substantially constant thickness.

[0233] According to certain embodiments, the coating has a thickness strictly greater than 1000 μm, for example 1 to 2 mm.

[0234] According to certain embodiments, the grafted primer layer has a thickness generally not exceeding 20%, preferably not exceeding 10%, preferably not exceeding 5%, and more preferably not exceeding 1% of the thickness of the coating of fluoropolymer(s). One or more annealing steps may be carried out after the formation of the coating to increase the crystallization of the fluoropolymer in a manner known per se. Each annealing step may be carried out at a temperature ranging from 50°C to 150°C, and preferably from 70°C to 140°C.

[0235] The composite formed by the stacking of the substrate, the layer of primer(s) on the substrate and the coating of PF fluorinated polymer(s) generally exhibits very good adhesion to the substrate / primer(s) interface and to the primary(s) / PF fluorinated polymer(s) interface, so that in the examples presented below the ruptures observed during the application of shear force to the interface of the primer / PF fluorinated polymer, only cohesive type ruptures of the PF fluorinated polymer could be observed.

[0236] In embodiments where the fluoropolymer is a ferroelectric polymer, for example P(VDF-TrFE), the composite formed by the stack of the substrate, the primer layer and the fluoropolymer PF coating, can then be polarized according to methods known per se: by contact polarization by applying a direct or alternating voltage or by non-contact polarization using the Corona effect.

[0237] Device

[0238] The invention also relates to a device comprising such a composite. The coating of fluorinated polymer(s) may be electroactive, be an insulating and / or protective coating, or even be an electrode binder.

[0239] The device may in particular be an optoelectronic device, a transistor, in particular a field effect transistor, a chip, a battery, a photovoltaic cell, a light-emitting diode, in particular an organic light-emitting diode, a sensor, an actuator, a transformer, a haptic device, a microelectromechanical system and a detector. a reactive function and a good affinity for fluorinated eras

[0240] The synthesis of different random copolymers that can be used as adhesion primer precursors according to the invention was carried out in solution by controlled radical polymerization. A first copolymer, referred to as "MGH" hereinafter, is a random type copolymer obtained by bringing together in the reaction medium methyl methacrylate (MMA), glycidyl methacrylate (GMA) and 2-hydroxyethyl methacrylate (HEMA), so as to obtain a P(MMA-GMA-HEMA) having a mass proportion of MMA / GMA / HEMA of 65 / 20 / 15.

[0241] A second copolymer, hereinafter referred to as “MGHT”, is a random type copolymer manufactured by bringing together in the reaction medium methyl methacrylate (MMA), glycidyl methacrylate (GMA), 2-hydroxyethyl methacrylate (HEMA) and tert-butyl methacrylate (MtBu), so as to obtain a P(MMA-GMA-HEMA-MtBu) having a mass proportion MMA / GMA / HEMA / MtBu) of 65 / 15 / 10 / 10.

[0242] MGH and MGHT copolymers have a particular affinity for fluoropolymers, in particular PVDF and VDF-based copolymers, due in particular to their high proportion of MMA repeat units, and comprise repeat units comprising at least one reactive function capable of crosslinking the polymer.

[0243] The process of obtaining photo-crosslinked films was carried out as follows (bar-coating, UV irradiation, annealing, rinsing).

[0244] Four solutions sia, si b, S2 and S3 were first prepared.

[0245] The sia solution corresponds to a solution in which the MGH copolymer has been dissolved in methyl ethyl ketone (MEK) at a concentration of 5% by mass.

[0246] The sib solution corresponds to a solution in which the MGHT copolymer has been dissolved in MEK at a rate of 5% by mass.

[0247] Solution S2 corresponds to a solution in which the SpeedCure® BPO product, marketed by Lambson, was dissolved in the same solvent (MEK, alternatively but not implemented PGME) at a rate of 5% by mass.

[0248] Solution S3 corresponds to a solution in which the SpeedCure® EHA product marketed by Lambson has been dissolved in MEK at a rate of 5% by mass.

[0249] The three solutions sia, S2 and S3 on the one hand and si b, S2 and S3 on the other hand were mixed with a mass ratio of 90 / 5 / 5 respectively. Each mixture thus obtained was dispensed by bar-coating on a portion of a 15 pm thick 1235 aluminum substrate while another portion of the aluminum substrate remained bare, then was dried under ambient atmosphere (23 ° C). Each of the films obtained was then irradiated under LED type UV lamps, at a wavelength of 385 nm (Keol-LED 100 type lamp, marketed by the company Keol Solution Collage), for a dose of 100 mJ.crrr 2. The substrates coated with the crosslinked films were finally annealed at 140°C for 3 minutes, then rinsed in a MEK bath for 10 minutes. The films did not dissolve after rinsing. Since MEK is an excellent solvent for PVDF and VDF-based copolymers, this point guarantees good film integrity during subsequent coating of a PVDF film or a VDF-based copolymer.

[0250] Alternative solvents for preparing solutions sia, sib, S2 and S3 could have been PGME or a PGME-ethanol mixture.

[0251] Examples 2b: Thermocrosslinking on the surface of a substrate of random copolymers comprising at least one repeating unit before a reactive function and having good affinity for fluorinated polymers

[0252] The same 5% by mass MGH and MGHT copolymer solutions in MEK as in Example 2a were used [solutions sia and sib].

[0253] A solution of ammonium triflate was prepared at 5% by mass in MEK [solution S4].

[0254] The two solutions sia and S4 on the one hand and sib and S4 on the other hand were mixed with the mass ratio 90 / 10. Each mixture thus obtained was dispensed by bar-coating on a portion of a 15 pm thick 1235 aluminum substrate while another portion of the aluminum substrate remained bare, then was dried under ambient atmosphere.

[0255] The difference with example 2a is that the crosslinks were implemented thermally during annealing and did not require UV radiation. Indeed, for this example the solutions comprising the adhesion primer precursor were dispensed by bar coating on a portion of a 15 μm thick 1235 aluminum substrate while another portion of the aluminum substrate remained bare, then dried in ambient atmosphere. The substrate was then annealed at 140°C for 20 minutes, then rinsed in a MEK bath. The films did not dissolve following rinsing. crosslinking on the surface of a substrate at least one unit of a reactive function and poor affinity for fluoropolymers

[0256] The synthesis of different random copolymers which cannot be used as adhesion primer precursors according to the invention was carried out in solution by controlled radical polymerization.

[0257] A first comparative copolymer, denoted “FGH” hereinafter, is a random type copolymer obtained by bringing together in the reaction medium glycidyl methacrylate (GMA), 2-hydroxyethyl methacrylate (HEMA) and 2,2,2-trifluoroethyl methacrylate (MATRIFE) so as to obtain a P(GMA-HEMA-MATRIFE) having a mass proportion of MMA / GMA / HEMA of 27 / 26 / 47.

[0258] A second comparative copolymer, denoted "GHT", is a random type copolymer obtained by bringing together in the reaction medium glycidyl methacrylate (GMA), 2-hydroxyethyl methacrylate (HEMA), and tert-butyl acrylate (AtBu), introduced into the reaction medium in such a way as to obtain a P(GMA-HEMA-AtBu) having a mass proportion of GMA / HEMA / AtBu of 25 / 42 / 33.

[0259] Like the MGH and MGHT copolymers of Example 2a, the FGH and GHT copolymers of Comparative Example 2a have repeating units comprising at least one crosslinkable reactive function. Unlike the MGH and MGHT copolymers of Example 2a, the FGH and GHT copolymers of Comparative Example 2a have a poor affinity for fluoropolymers, in particular due to the absence of an MMA repeating unit in their structure.

[0260] The process for obtaining photocrosslinked films of FGH and GHT, each dissolved at 5% by mass in MEK, was similar to that implemented in Example 2a (bar-coating, UV irradiation, annealing, rinsing). crosslinking on the surface of a substrate of at least one rehearsal unit a reactive function and a bad affinity THE The process for obtaining thermocrosslinked films of FGH and GHT, each dissolved at 5% by mass in MEK, was similar to that implemented in example 2b (bar-coating, annealing, rinsing).

[0261] Example 3a: Photocrosslinking on the surface of a substrate of a block copolymer comprising at least one repeating unit before a reactive function and having good affinity for fluorinated polymers

[0262] A block copolymer, PMMA-bP(HEA-co-GMA) was synthesized in solution by controlled radical polymerization, by sequentially introducing into the reaction medium methyl methacrylate (MMA) and a mixture of 2-hydroxyethyl acrylate (HEA) and glycidyl methacrylate (GMA) introduced into the reaction medium so as to obtain a PMMA-bP(HEA-co-GMA) block copolymer having a mass proportion of MMA / HEA / GMA of 85 / 14 / 1.

[0263] The process for obtaining a photocrosslinked film from a solution of PMMA-bP(HEA-co-GMA) dissolved at 5% by mass in MEK was similar to that implemented in example 2a (bar-coating, UV irradiation, annealing, rinsing).

[0264] Example 3b: Thermocrosslinking on the surface of a substrate of a block copolymer comprising at least one repeating unit before a reactive function and having good affinity for fluorinated polymers.

[0265] The process for obtaining a thermocrosslinked film from a solution of PMMA-bP(HEA-co-GMA) dissolved at 5% by mass in MEK was similar to that in example 2b (bar-coating, annealing, rinsing).

[0266] Examples 4a: Photocrosslinking of an MGH+PMMA-bP(HEA-co-GMA) mixture on a substrate

[0267] For this example, a blend of the MGH copolymer described in Example 2a with the PMMA-bP(HEA-co-GMA) block copolymer described in Example 3a was prepared, in a mass proportion of MGH / PMMA-bP(HEA-co-GMA) 80 / 20. A solution of the polymer blend at 5% by mass in MEK was prepared and the procedure described in Example 2a for photocrosslinking (bar-coating, UV irradiation, annealing, rinsing) was followed.

[0268] 4b: Thermocrosslinking of a MGH+PMMA-bP(HEA-co- mixture on a substrate

[0269] For this example, a blend of the MGH copolymer described in Example 2a with the PMMA-bP(HEA-co-GMA) block copolymer described in Example 3a was prepared, in a mass proportion of MGH / PMMA-bP(HEA-co-GMA) 80 / 20. A solution of the polymer blend at 5% by mass in MEK was prepared and the procedure described in Example 2b for thermal crosslinking (bar-coating, annealing, rinsing) was followed. PF-1 fluorinated era on substrates coated with i- or thermo-crosslinked according to the 2a, 2b, 3a, 3b, 4a and

[0270] 4b and comparative examples 2a, 2b.

[0271] A P(VDF-TrFE) copolymer, consisting of repeating units derived from vinylidene fluoride (VDF) and trifluoroethylene (TrFE), having a VDF:TrFE molar ratio of 80.0:20.0 (Piezotech®FC20, marketed by Arkema), was used as a fluoropolymer. This polymer is referred to as “PF-1” in the following examples. A PF-1 solution was prepared at 10% by mass in methyl ethyl ketone (MEK).

[0272] The PF-1 solution was dispensed by bar-coating over the entire surface of the functionalized substrates (according to examples 2a, 2b, 3a, 3b, 4a and 4b and comparative examples 2a, 2b) or non-functionalized substrates (hereinafter referred to as comparative example 1: use of a 15 μm thick 1235 aluminum substrate without any primer) so as to obtain a wet film with a theoretical thickness of 500 μm, then the film was left to dry at room temperature for about fifteen minutes. The film was then placed in an oven for 20 minutes at 140°C in order to increase the crystallinity of PF-1. Then the film was rapidly cooled to room temperature.

[0273] The substrates thus prepared were cut into strips of 25 mm sides to carry out an adhesion test. The samples made from the substrates treated in Examples 2a, 2b, 3a, 3b, 4a and 4b and Comparative Examples 2a, 2b all include a part where the PF-1 film rests on the area where a primer (crosslinked precursor) has been applied and a part where it rests directly on the aluminum substrate. The control sample corresponds to a PF-1 film resting on the entire aluminum substrate (Comparative Example 1).

[0274] The samples produced were tested on an Instron 5565 type tensile testing machine, equipped with a 100 N force sensor, via a 180° peel test carried out at a speed of 0.5 mm / s, according to the diagram described in Figure 1. With reference to this figure, the PF-1 film 3, deposited on the aluminum substrate 1 comprising an adhesion primer 2 on a part of its surface (except the control which does not include a primer layer) undergoes a 180° peel test by applying a tensile force 4.

[0275] The results of these tests are presented in Table 1 below. The column titled “Tensile Force” represents the force used during the peel test and is expressed in Newtons per 25 mm (N / 25mm). Two types of failure were observed: either an adhesive type failure (“A”) between two layers, or a cohesive type failure of a material in a given layer (“C”).

[0276] [Table 1]

[0277] Thus, the primer precursors according to the invention make it possible, once crosslinked, to obtain very good adhesion of a fluoropolymer with the treated substrate since the measured adhesion force is very high and the type of rupture is cohesive (rupture of the PF-1 coating itself).

[0278] Example 6: Electroactive properties of fluoropolymer PF-1 on substrates coated with thermally crosslinked primers according to Examples 2a, 2b, 3a, 3b, 4a and 4b and Comparative Examples 2a, 2b.

[0279] The samples were prepared as for the adhesion tests except that the primer precursors were applied and crosslinked over the entire substrate surface. The thickness of the primer layers after solvent evaporation and crosslinking was about 200 nm. The thickness of the PF-1 coating was about 30 μm after solvent evaporation.

[0280] The electroactive properties of the obtained films were evaluated as follows: each film was placed between two gold electrodes on the sample holder, then compressed to a height of 2.5 kN / crrr 2 under a hydraulic press to ensure good contact between the film and the electrodes. An alternating voltage was then applied to the electrode terminals so as to obtain an electric field depending on the thickness (15 pm) of the film, ranging from 25 V / pm up to 150 V / pm in steps of 5 V / pm. The remanent polarization (P r ) of the film considered was then extracted from the hysteresis curve obtained at 150 V / pm.

[0281] The results of this test are shown in Table 2 below.

[0282] [Table 2]

[0283] Thus, the primer precursors according to the invention make it possible, once crosslinked, to obtain very good adhesion of an electroactive fluorinated polymer with the treated substrate without, however.

[0284] Example 7: Electron beam (e-beam) crosslinking of MGH copolymer on a silicon substrate

[0285] The equipment used for e-beam lithography is a JEOL 6300FS device operating at 100kV, with the electron beam intensity set at 5nA; a different exposure dose is tested for each sample, of 30pC / cm 2 at 180pC / cm 2 , in steps of 30pC / cm 2 .

[0286] The example below was carried out with an MGH copolymer as synthesized according to example 2a; the behavior of the material with respect to crosslinking by e-beam would however be identical with the other crosslinkable primer precursors according to the invention.

[0287] A 2% by mass solution of MGH copolymer was prepared in absolute ethanol. A 2% by mass solution of triphenylsulfonium trifluoromethanesulfonate (hereinafter abbreviated as "TPST") was also prepared in absolute ethanol. A solution of MGH and TPST mixture was then prepared at a ratio of 90% MGH to 10% TPST, by mass. The resulting solution was filtered through a PTFE filter with a porosity of 200nm, then dispensed by spin-coating at 2000rpm onto a 3cm silicon substrate, to obtain a homogeneous film of approximately 60nm thickness. A gentle annealing was then carried out at 60°C for 1 minute to remove residual solvent traces from the copolymer film, then the sample was exposed to an electron beam at a precise dose to draw rectangular patterns of 200pmx100pm spaced 400pm apart.After exposure, a post-exposure annealing was performed at 90°C for 2 minutes to allow the diffusion of the electro-generated acid into the MGH film. The sample was then rinsed in an absolute ethanol bath for 1 minute to remove the unexposed areas of the substrate, then the residual solvent was removed under nitrogen flow. The sample thus prepared was then cleaved so that the fracture performed cuts the drawn patterns, then the residual thickness corresponding to the crosslinked MGH copolymer was estimated by scanning electron microscopy via a cross-sectional view on the drawn patterns.

[0288] The thickness values ​​thus determined were reported in Figure 2. It is thus demonstrated that the MGH copolymer can be crosslinked via an electron beam, and that if an area of ​​the film is not exposed to the beam, it will be eliminated during the solvent rinsing step. The example therefore shows that areas of the film can be specifically selected to undergo a crosslinking reaction. It is noted that the sensitivity of the material to the beam can be easily modified by adjusting various parameters well known to those skilled in the art (ratio of constituents, chemical nature of the sulfonium salt, etc.)

[0289] Example 8: UV patterning crosslinking of MGH copolymer on a silicon substrate

[0290] The UV unit used is a MJB4 mask aligner designed by Süss MicroTec. It includes a UV lamp delivering a power of ~12W.crrr 2at the wavelength 365 nm located a few centimeters above the sample. The sample is first placed on the dedicated sample holder, then the lithography mask is placed on the sample by contact, and the lamp is switched on for a defined time corresponding to a given light dose of ~300 mJ / cm 2

[0291] The example below was carried out with an MGH copolymer as synthesized according to example 2a. The behavior by UV patterning would however be identical with the other adhesion primer precursors according to the invention.

[0292] A 2% by mass MGH copolymer solution was prepared in absolute ethanol. A 4% by mass solution of the PAG "TAPS" initially in 50% solution in propylene carbonate was prepared in methanol. A solution of MGH and TAPS mixture was then prepared at 90% MGH for 10% TAPS, by mass. The solution thus obtained was filtered on a PTFE filter with a porosity of 200nm, then dispensed by spin-coating at 2000rpm on a silicon substrate of 3cm side, so as to obtain a homogeneous film of approximately 60nm thickness. A gentle annealing was then carried out at 60°C for 1 minute in order to remove residual solvent traces from the copolymer film, then the sample was placed on the sample holder of the mask aligner and then subjected to a specific dose of light radiation through the lithography mask (arbitrary line-type patterns of variable dimensions up to 1 pm in width, for example).Subsequently, a post-exposure annealing was carried out at 90°C for 2 minutes on a simple hot plate to allow the diffusion of the photo-generated acids into the copolymer film, then the sample was rinsed in an absolute ethanol bath for 2 minutes to remove the non-crosslinked copolymer chains and the residual solvent was evacuated under nitrogen flow. The sample thus prepared was then observed under an optical microscope and by SEM to observe the drawn patterns. The gray / black areas that stand out correspond to the patterns drawn via crosslinking of the MGH copolymer.

[0293] The example therefore clearly demonstrates that the MGH copolymer can be used as a resin for optical lithography via UV radiation in order to draw patterns of nanometric dimensions of interest allowing the local modulation of the adhesion force of a film based on fluoropolymer subsequently dispensed on this first layer.

[0294] Example 9: Thermocrosslinking of MGH copolymer on a silicon substrate at different annealing temperatures

[0295] The thermally induced crosslinking reaction of the adhesion primer precursors used can be demonstrated as follows: a solution of MGH material and ammonium triflate (mass ratio 9 / 1) at 2% by mass in ethanol is dispensed by spin-coating onto a silicon substrate at 1500 rpm. Once dried, the deposit directly after dispensing measures approximately 70 nm in thickness (the thicknesses are measured by ellipsometry, on a UVISEL ellipsometer from Horiba Scientific). The different samples of identical initial thickness are then annealed using a hot plate, each at a different temperature, for two minutes. The samples were then rinsed in an ethanol bath to remove the non-crosslinked material, and dried under nitrogen flow, before measuring their respective thickness. The results are plotted in the graph in Figure 3.The graph shows that the material thickness after rinsing becomes constant and equivalent to the initial thickness for temperatures of the order of 100°C. Furthermore, it is notable to mention that without the thermal annealing carried out, the thickness measured for the material after rinsing is negligible: all of the material has been eliminated. The example therefore shows that the materials used in the context of the invention are capable of undergoing a crosslinking reaction in times and temperatures that are particularly advantageous for an industrial application requiring a high production rate.

Claims

Claims 1. Use of a reactive composition as a precursor for an adhesion primer between a substrate and a coating comprising at least one fluorinated polymer, said reactive composition comprising at least one PG polymer comprising a repeating unit derived from methyl methacrylate and at least one repeating unit comprising at least one reactive function, said at least one repeating unit derived from methyl methacrylate representing at least 40% by weight of the weight of said at least one PG polymer; said reactive composition comprising a photoinitiator and optionally a synergistic coinitiator such as derivatives comprising at least one amine or silyl type function.

2. Use according to claim 1, wherein said at least one repeating unit derived from methyl methacrylate represents at least 45%, or at least 50%, or at least 55%, or at least 60% by weight of said at least one PG polymer.

3. Use according to any one of claims 1 to 2, in which said at least one reactive function of at least one repeating unit of said at least one PG polymer is chosen from groups of the oxirane, aziridine or thiirane type.

4. Use according to claim 3, in which the photoinitiator is chosen from acid-generating photoinitiators (PAG), preferably from onium salts, in particular sulfonium, iodonium and pyridinium salts, ferrocene derivatives, nitrobenzyl ester type derivatives, sulfones, aryl phosphates, derivatives comprising N-hydroxysuccinimide sulfonate functions, sulfonic acid esters; and base-generating photoinitiators (PBG), preferably from derivatives comprising O-acyloxime, benzoyloxycarnoyl or o-nitrobensoyloxycarbonyl, or formamide type functions.

5. Use according to any one of claims 1 to 4, wherein said at least one PG polymer comprises a repeating unit resulting from the polymerization of glycidyl methacrylate.

6. Use according to any one of claims 1 to 5, in which said at least one PG polymer comprises at least one repeating unit other than that derived from methyl methacrylate and that(s) comprising said at least one reactive function, said at least one other repeating unit being capable of grafting with said at least one reactive function and being chosen from the units resulting from the polymerization of non-(meth)acrylic silylated vinyl monomers, silylated styrenic monomers, acrylic acid, methacrylic acid, and alkyl esters of acrylic or methacrylic acid whose alkyl chain is substituted by at least one group chosen from -SiHs, alkylsilane, oxysilane, phosphonate, phosphonic acid, alcohol, amino, thiol, thioester.

7. Use according to claim 6, wherein said at least one other repeating unit capable of grafting with said at least one reactive function is chosen from units derived from the polymerization of acrylic acid, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate or 2-hydroxypropyl acrylate, methacrylic acid, and hydroxyalkyl methacrylates such as 2-hydroxyethyl methacrylate or 2-hydroxypropyl methacrylate.

8. Use according to claim 7, in which said at least one other repeating unit capable of grafting with said at least one reactive function is derived from 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate.

9. Use according to any one of claims 1 to 8, wherein said at least one PG polymer is a gradient or statistical type copolymer and comprises from 5% to 30% by weight of said at least one repeating unit comprising at least one reactive function, relative to the weight of the PG polymer.

10. Use according to claim 9, wherein said at least one PG polymer comprises from 40% to 95% by weight of unit of repetition resulting from the polymerization of methyl methacrylate, relative to the weight of the PG polymer.

11. Use according to any one of claims 9 and 10, in which said at least one PG polymer comprises at least one other repeating unit capable of grafting with said at least one reactive function according to any one of claims 6 to 8, said at least one other unit capable of grafting with said at least one reactive function representing from 1% to 30% by weight relative to the weight of the PG polymer.

12. Use according to any one of claims 1 to 8, wherein said at least one PG polymer is a block copolymer.

13. Use according to claim 12, wherein said at least one PG polymer comprises at least one block A comprising a repeating unit derived from methyl methacrylate and at least one block B comprising said at least one repeating unit comprising at least one reactive function.

14. Use according to claim 13, wherein said at least one block A does not comprise said at least one repeat unit comprising at least one reactive function.

15. Use according to any one of claims 13 and 14, wherein said at least one block B does not comprise a repeating unit derived from methyl methacrylate.

16. Use according to any one of claims 13 to 15, wherein said at least one PG polymer is a block polymer of type P(AbB) where A and B are the blocks as defined in claims 22 to 24.

17. Use according to any one of claims 13 to 16, wherein said at least one PG polymer comprises from 0.5% to 20% by weight of said at least one repeating unit comprising at least one reactive function, relative to the weight of the PG polymer.

18. Use according to claim 17, wherein said at least one PG polymer comprises from 60% to 99.5% by weight of repeating unit derived from methyl methacrylate, relative to the weight of the PG polymer.

19. Use according to any one of claims 17 and 18, in which said at least one PG polymer comprises at least one other repeating unit capable of grafting with said at least one reactive function according to any one of claims 6 to 8, said at least one other repeating unit capable of grafting with said at least one reactive function representing from 0.5% to 20% by weight relative to the weight of the PG polymer.

20. Use according to claim 19, in which said at least one PG polymer comprises at least one block A comprising a repeating unit derived from methyl methacrylate and at least one block B comprising said at least one repeating unit comprising at least one reactive function and said at least one other repeating unit capable of grafting with said at least one reactive function.

21. Use according to claim 20, wherein said at least one block A does not comprise said at least one other repeat unit capable of grafting with said at least one reactive function.

22. Use according to any one of claims 1 to 21, in which said at least one PG polymer is chosen from: - a statistical or gradient copolymer resulting from the polymerization of methyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate, - a random or gradient copolymer of methyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate and tert-butyl methacrylate, - an AB-type block copolymer, where block A is a methyl methacrylate block and block B is a block resulting from the polymerization of glycidyl methacrylate and 2-hydroxyethyl methacrylate, and - their mixture.

23. Use according to any one of claims 1 to 22, wherein said reactive composition comprises a compound M not comprising said reactive function and comprising a function chosen from: nitroxy, -SiHs, alkylsilane, oxysilane, phosphonate, phosphonic acid, alcohol, amino, thiol, and thioester.

24. Use according to any one of claims 1 to 23, wherein said at least one fluoropolymer comprises at least 40 mol% of repeating unit derived from vinylidene fluoride, relative to the total sum of moles of repeating units constituting said polymer, and optionally at least one repeating unit derived from a monomer X, other than vinylidene fluoride, having the formula CXiX2=CX3X4, in which each group Xi, X2, X3 and X4 is independently chosen from H, Cl, F, Br, I and C1-C3 alkyl groups which are optionally partially or totally halogenated.

25. Use according to any one of claims 1 to 24, wherein said at least one fluoropolymer is a P(VDF-TrFE), a P(VDF-TrFE-CTFE), a P(VDF-TrFE-CFE), or a mixture thereof.

26. A method of manufacturing a coating based on fluorinated polymer(s) on a substrate to be treated comprising the steps of: i) depositing a reactive composition as defined in claims 1 to 25 on the surface of the substrate to be treated; ii) removing the solvent possibly present in the composition deposited in step i) on the surface of the substrate to be treated; iii) crosslinking at least a portion of said at least one PG polymer on the surface of the substrate so as to obtain a substrate covered with a layer comprising the at least partly crosslinked PG polymer; iv) optionally, annealing after step iii), preferably at a temperature of between 100°C and 150°C; v) recovering the treated substrate coated with a primer layer comprising the crosslinked PG polymer, to form a substrate coated with a primer layer comprising a crosslinked PG polymer;vi) depositing a composition comprising at least one fluoropolymer on said primary layer obtained in the preceding step; vii) where appropriate, removing the solubilization solvent for said at least one fluoropolymer possibly present in said composition comprising said at least one fluoropolymer; and viii) recovering the treated substrate coated with said at least one fluoropolymer.; 27. Composite C2 comprising a coating R2 comprising, being essentially constituted, or being constituted of at least one fluoropolymer, said coating R2 adhering to a composite C1, said composite C1 comprising a layer R1 based on at least one PG polymer crosslinked on a substrate, said at least one PG polymer being said at least one PG polymer according to any one of claims 1 to 25, wherein said coating R1 adheres to said coating R2.

28. Device comprising a composite C2 according to claim 27, wherein said coating R2 is an electroactive coating, or an insulating and / or protective coating, or an electrode binder.

Images