Single layer improved in adhesion strength to metalized surface

Abstract

To provide a single layer containing a fluoropolymer, which exhibits very high adhesion strength to a substrate while being active, shows electrically active characteristics, and is flexible.SOLUTION: The present invention relates to a single layer comprising a fluoropolymer, a silicon-sulfur compound, and a vinyl polymer composed of carbon and hydrogen atoms and optionally oxygen and / or nitrogen atoms, a substrate and an assembly comprising the single layer, a method for preparing the single layer, a component comprising the single layer, and a device comprising the component.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to monolayers that exhibit improved long-lasting adhesive strength to substrates, especially metallized substrates, especially under aqueous conditions.

[0002] The present invention also relates to a method for preparing such a monolayer and to the use of such a monolayer. [Background technology]

[0003] Fluoropolymers, such as materials containing polyvinylidene fluoride, are known in particular for their excellent dielectric and / or piezoelectric properties and can be very useful in a wide range of applications, especially in electronic applications. In many applications, they are used in the form of coating or printing layers, and it is essential that these layers exhibit good adhesive properties.

[0004] However, fluoropolymers have very poor adhesion strength to metals, which adversely affects their use in electronic applications where a metal substrate may be required as the substrate.

[0005] To overcome this problem, several solutions have been developed. Methods to promote adhesion of fluoropolymers to metal substrates include the use of grafted polymers. However, sourcing and using these materials can be difficult, limiting their utility for large-scale, mass-produced industrial applications.

[0006] Another solution involves the development and use of specific adhesive layers to bond the fluoropolymer layer to the metal substrate. Such layers can include acrylic, epoxy, silane-based, or thiol-based compounds. However, the main problem associated with this solution is that the presence of at least one additional layer as an adhesive layer between the fluoropolymer layer and the substrate results in a multilayer structure. Multilayer structures suffer from the following drawbacks: surface brittleness, increased thickness, reduced flexibility and pliability, delamination due to high voltage or high frequency (ultrasonic vibration), delamination due to moisture, additional manufacturing steps (printing or coating) that are difficult to handle when patterns or shapes overlap, reduced dielectric performance / electrical conductivity, limitations due to cutting (edges), and delamination / peeling due to use (rubbing, bending, scratching, sweat, etc.). Therefore, multilayer structures are not suitable for various applications in harsh environments where fluoropolymers may be considered.

[0007] One method of promoting adhesion of fluoropolymers to metal substrates is to add a sulfur-containing adhesion promoter in combination with the fluoropolymer.

[0008] For example, EP 3638733 discloses a composition comprising a fluoropolymer containing units derived from vinylidene fluoride and units derived from trifluoroethylene, and a silane agent.

[0009] JP2010182994 describes an organic piezoelectric material for an ultrasonic transducer suitable for high frequency and wide band, comprising a layer of an organic piezoelectric material containing a fluoropolymer and a material capable of forming a covalent bond with an electrode metal, the material containing a mercapto group as a functional group.

[0010] US20200239724 also describes a composition for producing a passivation layer, comprising a fluorocopolymer and a thiol-based adhesion promoter.

[0011] However, these prior art layers exhibit poor adhesion to metal substrates, especially after the layer and substrate assembly is immersed in an aqueous solution, a problem that is significant for end uses in harsh environments, especially in outdoor applications, electronic or medical devices, and other applications that come into contact with water. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] EP3638733 [Patent Document 2] JP2010182994 [Patent Document 3] US20200239724 Summary of the Invention [Problem to be solved by the invention]

[0013] Therefore, there is a need for a monolayer comprising a fluoropolymer that exhibits very high adhesive strength to substrates, particularly metal substrates, especially when the component is used in a device that comes into contact with fluids such as water.

[0014] There is also a need for monolayers comprising fluoropolymers that are active yet exhibit very high adhesive strength to substrates, particularly metal substrates. There is a particular need for monolayers that exhibit electroactive properties, particularly electrical or electronic or piezoelectric or dielectric or electrostrictive properties.

[0015] There is a particular need for a monolayer that exhibits these properties while being flexible. [Means for solving the problem]

[0016] Therefore, the present invention provides a fluoropolymer; a silicon-sulfur compound, vinyl polymers consisting of carbon and hydrogen atoms, and optionally oxygen and / or nitrogen atoms; The present invention relates to a monolayer comprising:

[0017] In fact, the inventors have found that in order to achieve very good adhesive strength to a single layer metal substrate, in particular to make the fluoropolymer and silicon-sulfur compound resistant to contact with aqueous solutions while maintaining the desired active properties of the fluoropolymer, the fluoropolymer and silicon-sulfur compound should be combined with a vinyl polymer.

[0018] The monolayer according to the invention has the following advantages: - A monolayer with at least two functions: adhesion to the substrate and electroactive properties (dielectric / semiconductive / piezoelectric / electric / electronic / electrostrictive). - It is a flexible layer. - has enhanced adhesion to substrates, in particular copper or gold, and in particular allows improved adhesion even when the amount of gold in the substrate is low (meaning when the quality of the gold layer is low, e.g. low gold purity, low density, low thickness and low uniformity of the gold layer), so that the use of the layer of the invention reduces the amount of gold required on the surface of the substrate, and therefore reduces production costs. - Resistant to immersion in aqueous solutions, the monolayer of the present invention is therefore adapted to withstand moisture, liquids and humid environments without the need for additional intermediate layers to avoid dielectric losses at the fluoropolymer layer / substrate interface. It can be applied to conductive substrates such as electrodes or conductive plates, in particular copper, gold, stainless steel, palladium, aluminum, and mixtures thereof.

[0019] In particular, the inventors have surprisingly discovered that the addition of silicon-sulfur compounds and vinyl polymers to fluoropolymers makes it possible to maintain electroactive properties. Indeed, certain applications require high levels of dielectric properties, such as permittivity. The use of fluoropolymers makes it possible to reach such performance levels, which would have been expected to decrease with the addition of adhesion promoters. In contrast, the present invention makes it possible to improve the adhesion of layers to substrates using non-dielectric adhesion promoters, while preserving electroactive properties, such as dielectric properties. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram of the circuit used to measure the capacitance and dissipation factor of a polymer monolayer. DETAILED DESCRIPTION OF THE INVENTION

[0021] Fluoropolymer The monolayer of the present invention comprises at least one fluoropolymer. Fluoropolymers are fluorocarbon-based polymers, that is, they contain several carbon-fluorine bonds.

[0022] Fluoropolymers contain units derived from fluorinated monomers (fluoromonomers), which contain at least one carbon-fluorine bond.

[0023] Such fluoromonomers are preferably selected from: fluoromonomers of formula (I): C(X1)(X2)=C(X3)(X4) (I) wherein each of X1, X2, X3 and X4 is independently selected from H, Cl, Br, F, I and optionally partially or fully halogenated C1-C6 linear or branched alkyl groups, preferably methyl or ethyl groups, provided that at least one of X1, X2, X3 and X4 contains at least one fluorine atom; perfluoro(alkyl vinyl ethers) of the formula Rx-O-CF=CF2, where Rx is a C1-C8, preferably C1-C4, linear or branched alkyl group, such as perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether) (PEVE), and perfluoro(propyl vinyl ether) (PPVE), perfluoro(meth)acrylates of formula Ry-O-(O)C-CF=CF2, where Ry is H or a C1-C8, preferably C1-C4, linear or branched alkyl group, fluoro(meth)acrylates of formula Rz-O-(O)C-CH=CH2, where Rz is a C1-C8, preferably C1-C4, linear or branched alkyl group containing at least one, preferably three, fluorine atoms, - C3-C6 perfluorocycloalkenes (tetrafluorocyclopropene, hexafluorocyclobutene, octafluorocyclopentene, decafluorocyclohexene), - perfluoro(1,3-dioxole), - perfluoro(2,2-dimethyl-1,3-dioxole) (PDD), fluoromonomers of formula CF2=C(F)O-CF2CF(CF3)-O-CF2CF2-X, where X is CO2H, CH2OH, CO2CH3, SO2F, CH2OPO3H or CH2OCN, fluoromonomers of formula CF2=C(F)-O-CF2CF2SO2F, Formula: R-CH2-O-CF=CF2 (wherein R is H or F(CF2) m and m is 1, 2 or 3, Formula: R'-O-CF=CH2 (wherein R' is F(CF2) n - and n is 1, 2, or 3, or - Formula:F(CF2) z Fluoromonomers of the formula CH2-O-CF=CF2 (where z is 1, 2, 3, 4, or 5).

[0024] The fluoropolymer preferably comprises units derived from a fluoromonomer of formula (I).

[0025] Preferably, in formula (I), each of X1, X2, X3 and X4 is independently selected from H, F, Cl, I, Br or a methyl group optionally containing one or more substituents selected from F, Cl, I and Br, more preferably independently selected from H, F, Cl, Br or a methyl group optionally containing one or more substituents selected from F, Cl and Br, even more preferably independently selected from H, F, Cl or a methyl group optionally containing one or more substituents selected from F and Cl, advantageously independently selected from H, F and a methyl group optionally containing one or more F, provided that at least one of X1, X2, X3 and X4 contains at least one fluorine atom.

[0026] According to an embodiment, each of X1, X2, X3 and X4 is independently selected from H, F, Cl, I and Br, preferably independently selected from H, F, Cl and Br, more preferably independently selected from H, F and Cl, even more preferably independently selected from H and F, provided that at least one of X1, X2, X3 and X4 comprises at least one fluorine atom.

[0027] According to another embodiment, only one of X1, X2, X3 and X4 is selected from Cl, I and Br, preferably Cl, and the other X1, X2, X3 and X4 are independently selected from H, F or C1-C3 alkyl, preferably C1-C2 alkyl, more preferably methyl, said alkyl or methyl optionally bearing one or more fluorine substituents, provided that at least one of X1, X2, X3 and X4 contains at least one fluorine atom.

[0028] Examples of fluoromonomers of formula (I) include: vinyl fluoride (fluoroethylene), vinylidene fluoride (VDF), 1,2-difluoroethylene, trifluoroethylene (TrFE), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), trifluoropropenes such as 3,3,3-trifluoropropene, tetrafluoropropenes such as 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene, 1,1,3,3,3-pentafluoropropene or 1, Pentafluoropropenes such as 2,3,3,3-pentafluoropropene, hexafluoropropene, hexafluoroisobutylene, 3,3,3-trifluoro-2-(trifluoromethyl)propene, perfluorobutylethylene (PFBE), bromofluoroethylene (1-bromo-1-fluoroethylene or 1-bromo-2-fluoroethylene), bromodifluoroethylene (1-bromo-2,2-difluoroethylene or 1-bromo-1,2-difluoroethylene), bromotrifluoroethylene (cis or trans-1-bromo-3,3,3-trifluoropropene or 2-bromo-3,3,3-trifluoropropene), chlorofluoroethylene (CFE) (1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene), chlorodifluoroethylene (1-chloro-2,2-difluoroethylene or 1-chloro-1,2-difluoroethylene), chlorotrifluoroethylene (CTFE) (cis or trans-1-chloro-3,3,3-trifluoropropene or 2 -chloro-3,3,3-trifluoropropene), bromotrifluoropropene, chlorotrifluoropropene, (1 or 2 or 3 or 4)-bromo-(1 or 2)-fluorobutene, (1 or 2 or 3 or 4)-chloro-(1 or 2)-fluorobutene, (2 or 3 or 4)-chloro-1,1-difluorobutene, (2 or 3 or 4)-bromo-1,1-difluorobutene, (3 or 4)-bromo-1,1,2-trifluorobutene, and (3 or 4)-chloro-1,1,2-trifluorobutene.

[0029] A fluoropolymer may be a homopolymer of a fluoromonomer or may be obtained by copolymerizing a fluoromonomer with one or more other fluoromonomers and / or other monomers that are not fluoromonomers to form a copolymer.

[0030] Copolymer means a polymer derived from several types of monomers. Copolymers according to the invention are in particular copolymers of two monomers (dipolymers) or of three different monomers (terpolymers).

[0031] Preferably, the total molar content of fluoromonomers in the fluoropolymer is 40% to 100%, preferably 50% to 95%, more preferably 60% to 90%, based on the total molar content of monomers in the fluoropolymer.

[0032] Monomers that are not fluoromonomers and that can be copolymerized with fluoromonomers are preferably selected from non-fluorinated ethylenic monomers.

[0033] Ethylenic monomers are molecules containing at least one carbon-carbon double bond. Preferably, non-fluorinated ethylenic monomers are of the formula: C(R1)(R2)=C(R3)(R4), where R1, R2, R3 and R4 are independently selected from the group consisting of a hydrogen atom, an aromatic group, preferably phenyl, a C1-C10, preferably C1-C4 linear, branched or cyclic, saturated or unsaturated hydrocarbon group, optionally further containing an ether, ester, nitrile, carboxyl, amine and / or amide group, optionally including the possibility that two groups from R1, R2, R3 and R4 may form a 5-, 6- or 7-membered ring.

[0034] Advantageously, the non-fluorinated ethylenic monomer is chosen from ethylene, propylene, methyl or ethyl vinyl ether, vinyl esters, allyl glycidyl ether, (meth)acrylic acid, (meth)ethyl(meth)acrylic acid, and vinyl acetate.

[0035] Preferably, the molar content (or molar ratio) of the first fluoromonomer in the fluoropolymer (particularly when the first fluoromonomer is vinylidene fluoride) is 40% to 98%, preferably 50% to 90%, more preferably 60% to 80%, and even more preferably 60% to 70%. Preferably, the molar content of the second fluoromonomer in the fluoropolymer is 2% to 60%, preferably 10% to 50%, more preferably 20% to 40%, and even more preferably 30% to 40%, relative to the total molar content of the monomers in the fluoropolymer.

[0036] According to an embodiment, the fluoropolymer is a dipolymer of two different fluoromonomers, namely a first fluoromonomer and a second fluoromonomer, each independently as described above.

[0037] Preferably, the fluoropolymer is a terpolymer of at least three different fluoromonomers, i.e., a first fluoromonomer, a second fluoromonomer, and a third fluoromonomer, each independently as described above.

[0038] Terpolymers are particularly advantageous since they make it possible to obtain high electroactive properties, in particular high dielectric properties and especially high piezoelectric properties.

[0039] The fluoropolymer may comprise or consist of a first fluoromonomer unit and a second fluoromonomer unit. The fluoropolymer may also comprise or consist of a first fluoromonomer unit, a second fluoromonomer unit and a third fluoromonomer unit.

[0040] In particular, the fluoropolymer is a copolymer of vinylidene fluoride (as the first fluoromonomer) and at least one second fluoromonomer (the second fluoromonomer is a fluoromonomer as described above, with the proviso that it is different from vinylidene fluoride). More preferably, the fluoropolymer is a terpolymer of vinylidene fluoride (as the first fluoromonomer), the second fluoromonomer, and a third fluoromonomer, with the proviso that the second and third fluoromonomers are different from vinylidene fluoride and different from each other.

[0041] The fluoropolymer may comprise vinylidene fluoride units and second fluoromonomer units (and third fluoromonomer units, if present) or may consist of vinylidene fluoride units and second fluoromonomer units (and third fluoromonomer units, if present).

[0042] The second fluoromonomer is preferably a fluoromonomer of formula (I) above.

[0043] If present, the third fluoromonomer is preferably a fluoromonomer of formula (I) above.

[0044] Preferably, the fluoropolymer is a copolymer, preferably a dipolymer, of vinylidene fluoride and (at least) a second fluoromonomer of formula (I), wherein each of X1, X2, X3 and X4 is independently selected from H, F, Cl, I, Br or a methyl group optionally containing one or more substituents selected from F, Cl, I and Br, preferably independently selected from H, F, Cl, Br or a methyl group optionally containing one or more substituents selected from F, Cl and Br, with the proviso that at least one of X1, X2, X3 and X4 contains at least one fluorine atom, and with the proviso that the second fluoromonomer is different from vinylidene fluoride.

[0045] More preferably, the fluoropolymer is a copolymer, preferably a dipolymer, of vinylidene fluoride and (at least) a second fluoromonomer of formula (I), wherein each of X1, X2, X3 and X4 is independently selected from H, Cl, F or a methyl group optionally containing one or more F or Cl, preferably H, F or a methyl group optionally containing one or more F, with the proviso that at least one of X1, X2, X3 and X4 contains at least one fluorine atom, and with the proviso that the second fluoromonomer is different from vinylidene fluoride.

[0046] According to an embodiment, the fluoropolymer is a copolymer, preferably a dipolymer, of vinylidene fluoride and (at least) a second fluoromonomer of formula (I), wherein each of X1, X2, X3 and X4 is independently selected from H, F, Cl, I or Br, preferably selected from H, F, Cl or Br, more preferably selected from H, F and Cl, with the proviso that at least one of X1, X2, X3 and X4 contains at least one fluorine atom, and with the proviso that the second fluoromonomer is different from vinylidene fluoride.

[0047] According to another embodiment, the fluoropolymer is a copolymer, preferably a dipolymer, of vinylidene fluoride and (at least) a second fluoromonomer of formula (I), wherein only one of X1, X2, X3 and X4 is selected from Cl, I and Br, preferably Cl and Br, and the other X1, X2, X3 and X4 are independently selected from H, F or C1-C3 alkyl, preferably C1-C2 alkyl, more preferably methyl, said alkyl or methyl optionally having one or more fluorine substituents, advantageously the other X1, X2, X3 and X4 are independently selected from H and F, with the proviso that at least one of X1, X2, X3 and X4 comprises at least one fluorine atom, and with the proviso that the second fluoromonomer is different from vinylidene fluoride.

[0048] Preferably, the fluoropolymer is a copolymer of vinylidene fluoride and (at least) vinyl fluoride (fluoroethylene), vinylidene fluoride (VDF), 1,2-difluoroethylene, trifluoroethylene (TrFE), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), trifluoropropenes such as 3,3,3-trifluoropropene, tetrafluoropropenes such as 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene, 1,1,3,3,3-pentafluoropropene or 1, Pentafluoropropenes such as 2,3,3,3-pentafluoropropene, hexafluoropropene, hexafluoroisobutylene, 3,3,3-trifluoro-2-(trifluoromethyl)propene, perfluorobutylethylene (PFBE), bromofluoroethylene (1-bromo-1-fluoroethylene or 1-bromo-2-fluoroethylene), bromodifluoroethylene (1-bromo-2,2-difluoroethylene or 1-bromo-1,2-difluoroethylene), bromotrifluoroethylene (cis or trans isomers), 1-bromo-3,3,3-trifluoropropene or 2-bromo-3,3,3-trifluoropropene), chlorofluoroethylene (CFE) (1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene), chlorodifluoroethylene (1-chloro-2,2-difluoroethylene or 1-chloro-1,2-difluoroethylene), chlorotrifluoroethylene (CTFE) (cis or trans 1-chloro-3,3,3-trifluoropropene or 2-chloro-3,3,3-trifluoropropene), bromo-3,3,3-trifluoropropene, ... and a copolymer, preferably a dipolymer, of a second fluoromonomer selected from bromotrifluoropropene, chlorotrifluoropropene, (1 or 2 or 3 or 4)-bromo-(1 or 2)-fluorobutene, (1 or 2 or 3 or 4)-chloro-(1 or 2)-fluorobutene, (2 or 3 or 4)-chloro-1,1-difluorobutene, (2 or 3 or 4)-bromo-1,1-difluorobutene, (3 or 4)-bromo-1,1,2-trifluorobutene, and (3 or 4)-chloro-1,1,2-trifluorobutene.

[0049] According to the most preferred embodiment, the fluoropolymer is a copolymer, preferably a dipolymer, of vinylidene fluoride and a fluoromonomer selected from (at least) hexafluoropropylene, chlorofluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene and trifluoroethylene, preferably selected from chlorofluoroethylene, chlorotrifluoroethylene and trifluoroethylene.

[0050] According to a preferred embodiment, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer of formula (I), and a third fluoromonomer of formula (I), wherein each of X1, X2, X3, and X4 is independently selected from H, F, Cl, I, Br, or a methyl group optionally containing one or more substituents selected from F, Cl, I, and Br, and preferably independently selected from H, F, Cl, Br, or a methyl group optionally containing one or more substituents selected from F, Cl, and Br, with the proviso that at least one of X1, X2, X3, and X4 contains at least one fluorine atom, and with the proviso that the second and third fluoromonomers are different from vinylidene fluoride and different from each other.

[0051] More preferably, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer of formula (I), and a third fluoromonomer of formula (I), wherein each of X1, X2, X3, and X4 is independently selected from H, Cl, F, or a methyl group optionally containing one or more F or Cl, preferably H, F, or a methyl group optionally containing one or more F, with the proviso that at least one of X1, X2, X3, and X4 contains at least one fluorine atom, and with the proviso that the second and third fluoromonomers are different from vinylidene fluoride and different from each other.

[0052] According to an embodiment, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer of formula (I), and a third fluoromonomer of formula (I), wherein each of X1, X2, X3, and X4 is independently selected from H, F, Cl, I, or Br, preferably selected from H, F, Cl, or Br, more preferably selected from H, F, and Cl, provided that at least one of X1, X2, X3, and X4 contains at least one fluorine atom, and provided that the second and third fluoromonomers are different from vinylidene fluoride and different from each other.

[0053] According to another embodiment, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer of formula (I) and a third fluoromonomer of formula (I), wherein only one of X1, X2, X3 and X4 is selected from Cl, I and Br, preferably Cl and Br, and the other X1, X2, X3 and X4 are independently selected from H, F or C1-C3 alkyl, preferably C1-C2 alkyl, more preferably methyl, said alkyl or methyl optionally having one or more fluorine substituents; advantageously, the other X1, X2, X3 and X4 are independently selected from H and F, with the proviso that at least one of X1, X2, X3 and X4 contains at least one fluorine atom, and the second and third fluoromonomers are different from vinylidene fluoride and are different from each other.

[0054] Preferably, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer, and a third fluoromonomer, the second and third fluoromonomers being independently selected from vinyl fluoride (fluoroethylene), vinylidene fluoride (VDF), 1,2-difluoroethylene, trifluoroethylene (TrFE), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), a trifluoropropene such as 3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, or 1,3,3,3-tetrafluoropropene. tetrafluoropropenes such as 1,1,3,3,3-pentafluoropropene or 1,2,3,3,3-pentafluoropropene, pentafluoropropenes such as hexafluoropropene, hexafluoroisobutylene, 3,3,3-trifluoro-2-(trifluoromethyl)propene, perfluorobutylethylene (PFBE), bromofluoroethylene (1-bromo-1-fluoroethylene or 1-bromo-2-fluoroethylene), bromodifluoroethylene (1-bromo-2,2-difluoroethylene or 1-bromo -1,2-difluoroethylene), bromotrifluoroethylene (cis or trans 1-bromo-3,3,3-trifluoropropene or 2-bromo-3,3,3-trifluoropropene), chlorofluoroethylene (CFE) (1-chloro-1-fluoroethylene or 1-chloro-2-fluoroethylene), chlorodifluoroethylene (1-chloro-2,2-difluoroethylene or 1-chloro-1,2-difluoroethylene), chlorotrifluoroethylene (CTFE) (cis or trans 1-chloro-3,3,3- trifluoropropene or 2-chloro-3,3,3-trifluoropropene), bromotrifluoropropene, chlorotrifluoropropene, (1 or 2 or 3 or 4)-bromo-(1 or 2)-fluorobutene, (1 or 2 or 3 or 4)-chloro-(1 or 2)-fluorobutene, (2 or 3 or 4)-chloro-1,1-difluorobutene, (2 or 3 or 4)-bromo-1,1-difluorobutene, (3 or 4)-bromo-1,1,2-trifluorobutene, (3 or 4)-chloro-1,1,2-trifluorobutene.

[0055] According to a most preferred embodiment, the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer, and a third fluoromonomer, the second and third fluoromonomers being independently selected from hexafluoropropylene, chlorofluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, and trifluoroethylene, preferably selected from chlorotrifluoroethylene, chlorotrifluoroethylene, and trifluoroethylene.

[0056] Preferably, the terpolymer is a polymer of vinylidene fluoride, trifluoroethylene (as the second fluoromonomer) and chlorotrifluoroethylene (P(VDF-TrFE-CTFE)) (as the third fluoromonomer), or a terpolymer of vinylidene fluoride, trifluoroethylene (as the second fluoromonomer) and chlorofluoroethylene (P(VDF-TrFE-CFE)) (as the third fluoromonomer).

[0057] Preferably, the molar content (or molar ratio) of vinylidene fluoride in the fluoropolymer is 40% to 98%, preferably 50% to 80%, more preferably 60% to 75%, and even more preferably 60% to 70%. Preferably, the molar content of the second fluoromonomer in the fluoropolymer is 15% to 45%, preferably 20% to 40%, and more preferably 25% to 30%, based on the total molar content of the monomers in the fluoropolymer. Preferably, the molar content of the third fluoromonomer in the fluoropolymer is 1% to 15%, preferably 3% to 12%, and more preferably 5% to 10%, based on the total molar content of the monomers in the fluoropolymer.

[0058] The weight average molar mass Mw of the fluoropolymer is preferably at least 100,000 g.mol -1 , preferably at least 200,000 g.mol -1 , more preferably at least 300,000 g.mol -1 , and even more preferably at least 400,000 g.mol -1and preferably from 200,000 to 1,000,000 g.mol -1 The molecular weight distribution can be determined by size exclusion chromatography (SEC).

[0059] The monolayer of the present invention preferably comprises 80% to 99.9% by weight, preferably 90% to 99.8% by weight, preferably 95% to 98.5% by weight of fluoropolymer relative to the total weight of the monolayer.

[0060] Silicon-sulfur compounds Silicon-sulfur compounds are compounds containing at least one silicon atom and at least one sulfur atom, preferably at least one silane group and / or at least one silazane group, and at least one sulfur atom, more preferably at least one silane group and at least one sulfur atom.

[0061] The silane group is preferably a group of formula: -Si(Ra)(Rb)(Rc), where Ra, Rb and Rc are each independently selected from H, OH, Alk and -O-Alk (Alk is a C1-C8 linear or branched alkyl group), preferably OH, Alk and -O-Alk.

[0062] A silazane group contains at least a Si-N bond, and preferably contains at least one nitrogen atom covalently bonded to one hydrogen atom and two silicon atoms (-Si-NH-Si- group).

[0063] Preferably, Ra, Rb and Rc are each independently selected from Alk and -O-Alk.

[0064] Preferably, Alk (or independently the Alk of the -O-Alk group) is a C1-C4 linear or branched alkyl group, more preferably a methyl or ethyl group, even more preferably a methyl group.

[0065] Preferably, in the silicon-sulfur compound, the sulfur atom of the thiol functional group is not directly bonded to a silicon atom.

[0066] More preferably, the sulfur atoms of the silicon-sulfur compound are present in the form of -S-(Rd) groups, where (Rd) is selected from the group consisting of H and organic moieties containing 1 to 30 carbon atoms and at least one nitrogen atom and / or at least one oxygen atom. Preferably, (Rd) is selected from the group consisting of H and organic moieties consisting of 1 to 30 carbon atoms, hydrogen atoms, and one or several nitrogen atoms and / or one or several oxygen atoms.

[0067] Preferably, the silicon-sulfur compound has the formula (II): (Rd)S-Rw-Si(Ra)(Rb)(Rc) (II) wherein Rw is a linear or branched or cyclic group containing 1 to 18 carbon atoms and optionally containing one or several oxygen and / or nitrogen atoms, and Ra, Rb, Rc and Rd are as described above according to any embodiment. More preferably, Rw is a C1-C12, preferably C1-C8, preferably C1-C6, preferably C1-C4, more preferably C2-C4 linear or branched, preferably linear alkyl or alkylene group, preferably an alkyl group.

[0068] According to a preferred embodiment, Rd is H. According to this embodiment, the silicon-sulfur compound is a mercaptosilane, i.e., a compound comprising at least one silane group and at least one thiol functional group (—SH).

[0069] Preferably, the silicon-sulfur compound is not polymeric.

[0070] Preferably, the silicon-sulfur compound is 800 g.mol -1 less than 600 g.mol -1 less than 400 g.mol -1 less than 250 g.mol-1 less than, preferably 80 g.mol -1 to 800 g.mol -1 The molecular weight is between .

[0071] Non-limiting examples of silicon-sulfur compounds include: - Octanethioic acid, S-[3-(triethoxysilyl)propyl] ester, 2-methyl -reaction products with 1,3-propanediol and 3-(triethoxysilyl)-1-propanethiol (EC number: 485-270-1), - 3-(triethoxysilyl)propanethiol (CAS number 14814-09-6), - 3-(dimethoxymethylsilyl)-2-methylpropanethiol (CAS number 14857-92-2), - 3-(methoxydimethylsilyl)propanethiol (CAS number 14857-97-7), - hexamethylene diisocyanate, oligomeric, reaction products with 3-aminopropylmethylamine, trimethylacetaldehyde and 3-trimethoxysilylpropane-1-thiol (CAS number 161278-26-8), - Pentaerythritol, propoxylated, reaction products with 3-isocyanato-3,5,5-trimethylcyclohexyl isocyanate and 3-trimethoxysilylpropane-1-thiol (CAS number 161308-00-5), - hexamethylene diisocyanate, trimer, reaction products with (3-aminopropyl)methylamine, benzaldehyde and 3-trimethoxysilylpropane-1-thiol (CAS number 162491-90-9), - 2-methyl-3-(triethoxysilyl)propanethiol (CAS number 17980-28-8), - 2-(triethoxysilyl)ethanethiol (CAS number 18236-15-2), - (Trimethylsilyl)methyl thiocyanate (CAS number 18293-51-1), - Trimethylsilyl isothiocyanate (CAS number 2290-65-5), - 3-(dimethoxymethylsilyl)propanethiol (CAS number 31001-77-1), - 1-allyl-3-[3-(triethoxysilyl)propyl]thiourea (CAS number 42168-36-5), - 3-trimethoxysilylpropane-1-thiol (CAS number 4420-74-0), - 4-(triethoxysilyl)butane-2-thiol (CAS number 57640-10-5), - 2-[3-(trimethoxysilyl)propyl]isothiouronium chloride (CAS number 58505-58-1), - 3-[tris(2-ethoxyethoxy)silyl]propanethiol (CAS number 67724-41-8), - 2-(trimethoxysilyl)ethanethiol (CAS number 7538-45-6), - a mixture of S-(3-trimethoxysilyl)propyl 19-isocyanato-11-(6-isocyanatohexyl)-10,12-dioxo-2,9,11,13-tetraazanonadecanethioate and S-(3-(trimethoxysilyl)propyl 17-isocyanato-9-(isocyanatohexyl-aminocarbonyl)-10-oxo-2,9,11-triazaheptadecanethioate (CAS number 85702-90-5), - 1,3-dibutyl-2-[3-(triethoxysilyl)propyl]isothiouronium chloride (CAS number 90210-34-7), - 1,3-diphenyl-2-[3-(triethoxysilyl)propyl]isothiourea, monohydrochloride (CAS number 90210-35-8), - 3-[tris(decyloxy)silyl]propanethiol (CAS number 93777-94-7), - 1-methyl-3-(triethoxysilyl)propyl thiocyanate (CAS number 94087-37-3), - 2-methyl-3-(triethoxysilyl)propyl thiocyanate (CAS number 94087-38-4), - 3-[tris(octyloxy)silyl]propanethiol (CAS number 94291-66-4).

[0072] Advantageous examples of silicon-sulfur compounds include: - 3-(triethoxysilyl)propanethiol (CAS number 14814-09-6), - 3-(dimethoxymethylsilyl)-2-methylpropanethiol (CAS number 14857-92-2), - 3-(methoxydimethylsilyl)propanethiol (CAS number 14857-97-7), - 2-methyl-3-(triethoxysilyl)propanethiol (CAS number 17980-28-8), - 2-(triethoxysilyl)ethanethiol (CAS number 18236-15-2), - 3-(dimethoxymethylsilyl)propanethiol (CAS number 31001-77-1), - 3-trimethoxysilylpropane-1-thiol (CAS number 4420-74-0), - 4-(triethoxysilyl)butane-2-thiol (CAS number 57640-10-5), - 3-[tris(2-ethoxyethoxy)silyl]propanethiol (CAS number 67724-41-8), - 2-(trimethoxysilyl)ethanethiol (CAS number 7538-45-6), - 3-[tris(decyloxy)silyl]propanethiol (CAS number 93777-94-7), - 3-[tris(octyloxy)silyl]propanethiol (CAS number 94291-66-4).

[0073] The monolayer of the present invention preferably comprises 0.05% to 10% by weight, preferably 0.10% to 5% by weight, preferably 0.50% to 3.0% by weight, preferably 0.75% to 2.5% by weight of silicon-sulfur compounds relative to the total weight of the monolayer.

[0074] vinyl polymer The monolayer of the present invention comprises at least one vinyl polymer consisting of carbon and hydrogen atoms, and optionally oxygen and / or nitrogen atoms.

[0075] Vinyl polymers contain units derived from one or several vinyl monomers.

[0076] A vinyl monomer refers to a small organic molecule that contains at least one carbon-carbon double bond.

[0077] Preferably, the vinyl monomer has the following formula: C(X)(X')=C(X'')(X'''), where X, X', X'' and X''' are independently selected from the group consisting of a hydrogen atom, an OH group, a COOH group, a CN group, an aromatic group, preferably a phenyl group, a saturated or unsaturated hydrocarbon group containing 1 to 10 carbon atoms, preferably 2 to 10 carbon atoms, said aromatic group or hydrocarbon group optionally further containing an OH group, an ester group, a carboxyl group, an amine group, a nitrile group, and / or an amide group.

[0078] The vinyl monomer is preferably selected from the group consisting of C2 to C8, preferably C2 to C4, alkenyl monomers, C4 to C12 diene monomers, acrylate monomers, styrene monomers, vinyl alcohols, vinyl acetate, acrylamide monomers, maleic acid, and acrylonitrile.

[0079] The vinyl polymer may also be an elastomer such as, but not limited to, a copolymer of acrylonitrile and ethylene, or a terpolymer of ethyl, acrylate and other vinyl monomers.

[0080] The vinyl polymer may also be a PVA copolymer, a copolymer of vinyl acetate and acrylic acid, or a polyacrylamide.

[0081] Preferably, the vinyl polymer is an acrylate polymer.

[0082] An acrylate polymer is a polymer based on (or derived from) acrylic acid or an acrylic acid derivative, and therefore comprises units derived from acrylate monomers.

[0083] An acrylate monomer is a molecule containing at least an ester functional group and an unsaturated C=C double bond directly connected to the carbon of the acid or ester functional group. In other words, an acrylate monomer is a vinyl monomer containing an ester group, i.e., two double-bonded carbon atoms are directly attached to a carbonyl group. Acrylate polymers belong to the family of vinyl polymers.

[0084] According to the present invention, acrylic acid is included in the definition of acrylate monomers.

[0085] Preferably, the acrylate polymer comprises units derived from an acrylate monomer of formula (III):

[0086] [ka]

[0087] wherein Xa and Xb are independently selected from H, a -CN group, and a C1-C8 linear, branched, or cyclic, saturated or unsaturated group containing 1 to 8 carbon atoms; and Xc is selected from H, a benzyl group, and a linear, branched, or cyclic, saturated or unsaturated aliphatic or aromatic group containing 1 to 24 carbon atoms, which may optionally be substituted with at least one OH group and / or one COOH group and / or may optionally be interrupted by at least one -O- atom.

[0088] Preferably, Xa and Xb are independently selected from H and C1-C8 straight or branched alkyl groups.

[0089] Preferably, Xa=H.

[0090] Preferably, Xb=H, a —CN group or a C1-C2 alkyl group, preferably H or a C1-C2 alkyl group, more preferably H or a methyl group.

[0091] Preferably, Xc is selected from: - saturated, linear or branched alkyl radicals of C1 to C24, preferably C1 to C16, more preferably C1 to C8, even more preferably C1 to C4, advantageously methyl or ethyl, and - an -AO-Rx group, where A is -CH2CH(OH)CH2- or -CH2CH(CH2OH)-, and Rx is a C10 to C22 linear or branched alkyl group.

[0092] More preferably, Xc is a saturated linear or branched alkyl group of C1 to C24, preferably C1 to C16, more preferably C1 to C8, even more preferably C1 to C4, advantageously methyl or ethyl.

[0093] The acrylate monomer may be an acrylate having an additional methyl group attached to Xb and Xc being a methyl group. The acrylate monomer may also be a methacrylate. One of the most common methacrylate polymers is polymethyl methacrylate (PMMA).

[0094] The acrylate monomer is in particular ethyl acrylate, ethyl methacrylate, butyl acrylate, ethylhexyl acrylate or a derivative.

[0095] The acrylate polymer may be a homopolymer of an acrylate monomer, preferably of formula (III), or may be obtained by copolymerizing an acrylate monomer with one or more other acrylate monomers and / or other monomers that are not acrylate monomers to form a copolymer.

[0096] For example, the acrylate polymer may be a copolymer of methyl acrylate and methyl methacrylate, a copolymer of ethyl acrylate and methyl acrylate, or a copolymer of butyl acrylate and 2-ethylhexyl acrylate.

[0097] The acrylate polymer may also be an acrylonitrile styrene (meth)acrylate terpolymer, a styrene-acrylonitrile copolymer with a grafted acrylic elastomer, or a copolymer of styrene and an acrylate monomer. Monomers that can be copolymerized with acrylate monomers that are not acrylate monomers are preferably selected from the vinyl monomers mentioned above, with the proviso that the vinyl monomer is not an acrylate monomer.

[0098] Monomers that are not acrylate monomers and can be copolymerized with acrylate monomers may be C2 to C8, preferably C2 to C4, alkenyl monomers, C4 to C12 diene monomers, styrene monomers, vinyl alcohols, vinyl acetate, acrylamide monomers, maleic acid, and acrylonitrile.

[0099] The acrylic monomer may be ethyl acrylate, butyl acrylate, ethylhexyl acrylate or a derivative.

[0100] The vinyl (co)monomer is preferably of the formula: C(X)(X')=C(X'')(X'''), where X, X', X'' and X'''' are as defined above.

[0101] Preferably, X=X'=H.

[0102] According to an embodiment, X=X'=H, X" is H or a C1-C2 alkyl group, preferably H, and X"' is -C6H5, -CN, -C(O)NH2, -NC4H6O, -C(O)NHC(CH3), -C(O)N(CH3), C(O)NHC(CH3)2(CH2)4CH3, and -C(O)NHC(CH3)2CH2S(O)(O)OH.

[0103] According to another embodiment, X=X'=H, X"=H or a C1-C2 alkyl group, preferably H, and X"' is -OC(O)-Xm, where Xm is a linear or branched C1-C18 alkyl group.

[0104] Preferably, the vinyl polymer is non-fluorinated, which means a vinyl polymer that does not contain any fluorine atoms.

[0105] According to an embodiment, the vinyl polymer is not sodium poly(meth)acrylate. In particular, the vinyl polymer is not a superabsorbent polymer. In particular, the vinyl monomer is not an alkali salt of acrylic acid or an acrylate monomer.

[0106] The monolayer of the present invention preferably contains 0.05% to 10.0% by mass, preferably 0.10% to 8.0% by mass, preferably 0.50% to 5.0% by mass, preferably 0.75% to 4.0% by mass of vinyl polymer relative to the total mass of the monolayer.

[0107] Single layer Preferably, the thickness of the monolayer according to the invention is between 0.1 μm and 50 μm, preferably between 0.5 μm and 40 μm, preferably between 1.0 μm and 30 μm, preferably between 1.0 μm and 20 μm, preferably between 2.0 μm and 10 μm.

[0108] Preferably, the total mass of the fluoropolymer, silicon-sulfur compound, and vinyl polymer in the monolayer accounts for more than 80% by mass, preferably more than 90% by mass, preferably more than 95% by mass, more preferably more than 98% by mass, preferably between 80% and 99.99% by mass, based on the total mass of the monolayer.

[0109] According to an embodiment, the monolayer is free of metal oxide particles, preferably free of metals, and more preferably free of inorganic crystals.

[0110] Preferably, the piezoelectric compound of the single layer is essentially an organic (preferably polymeric) piezoelectric compound.

[0111] Preferably, the monolayer is an active monolayer, preferably an electroactive monolayer. "Active monolayer" or "electroactive monolayer" means a monolayer that contains properties that respond to, interact with, or anneal the effects of an electric or magnetic field. Such active functionality can include direct or inverse piezoelectric, electronic, dielectric, semiconductive, electric, and / or electrostrictive capabilities.

[0112] In particular, the dielectric constant ε of a single layer at 10 kHz r is 15 to 40 F / m, preferably 18 to 35 F / m, and more preferably 20 to 30 F / m.

[0113] Dielectric constant ε r is 2.0 to 8.0 mm for a monolayer having a thickness between 2.9 and 3.2 μm, in particular according to the method described in the examples. 2 is determined on the surface of

[0114] In contrast to self-assembled monolayers (SAMs), monolayers exhibit strong interactions with the substrate, ensuring adhesive and dielectric properties. (Self-assembled monolayers of organic molecules are ordered, organized molecular assemblies that form spontaneously on surfaces by adsorption and contain domains of various sizes. In some cases, the molecules that form the monolayer do not interact strongly with the substrate.)

[0115] The present invention also relates to an assembly comprising a substrate and a monolayer according to the invention, wherein the monolayer is applied to at least one surface of the substrate or to part of the surface of the substrate. The monolayer is in contact with at least one surface of the substrate. The monolayer can be applied to the substrate as a thin film, either entirely or partially. The monolayer can be applied as a continuous or discontinuous surface, pattern, track, etc.

[0116] The substrate may be, in particular, glass, silicon, quartz, a polymeric material, a metal, or a mixed surface made up of several of these materials.

[0117] Preferably, the substrate is or comprises a metal, in particular selected from gold, stainless steel, copper and aluminium, chromium and silver.

[0118] Preferably, the substrate comprises a metal surface, in particular a gold, stainless steel, copper, aluminum, chromium or silver surface, more particularly a copper or gold surface. Preferably, the monolayer is applied onto and in contact with said metal surface.

[0119] According to an embodiment, the substrate comprises a gold surface, preferably consisting of gold.

[0120] According to another embodiment, the substrate comprises a copper surface, preferably consisting of copper.

[0121] More preferably, the substrate comprises (or consists of) gold, preferably a gold surface.

[0122] The substrate may be of any shape: it may be flat or contoured, smooth or rough, linear or curved, porous or non-porous.

[0123] Methods and Uses The present invention also relates to a method for producing a monolayer, preferably according to the present invention, comprising the step of applying a composition comprising at least a fluoropolymer, a silicon-sulfur compound, and a vinyl polymer onto a substrate to form a film on the substrate.

[0124] The present invention also relates to a method for producing an assembly comprising a substrate and the monolayer described above, the method comprising the step of applying onto the substrate a composition comprising at least a fluoropolymer, a silicon-sulfur compound, and a vinyl polymer.

[0125] The composition can be applied by any conventional coating, printing, or laminating method known to those skilled in the art. Coating methods can be batch or roll-to-roll (also called reel-to-reel or R2R), or roll-to-sheet or sheet-to-roll, or sheet-to-sheet. Preferred methods include roll-to-roll methods such as roll coating or roll printing, knife coating, curtain coating, dipping, roll coating, spin coating, spray coating, gravure coating, jet printing, flat or rotary screen printing, slot die, and light-induced forward transfer printing (LIFT).

[0126] The composition may further comprise a solvent. Preferably, the method further comprises a step of evaporating the solvent from the composition. The evaporation of the solvent is preferably carried out by heating and drying the film applied to the substrate, for example, at a temperature of 60 to 190°C. Drying can be carried out by any method, including, but not limited to, air drying, hot plate drying, infrared drying, laser drying, and microwave drying. Drying is preferably carried out by passing the liquid composition applied to the substrate through a furnace, stenter, or oven, for example, in a roll-to-roll manner. Alternatively, the film can be formed by batch drying or curing. The drying temperature varies depending on the type and content of the solvent. The drying temperature and time can also be affected when a blend of solvents is used.

[0127] The composition can be prepared by blending or mixing or coupling together the fluoropolymer, the silicon-sulfur compound, and the vinyl polymer, preferably by dissolving the fluoropolymer, the vinyl polymer, and the silicon-sulfur compound in a suitable solvent.

[0128] The present invention also relates to a part comprising a monolayer according to the present invention. Preferably, in the part, the monolayer is coated on a substrate. No pretreatment, such as corona pretreatment, is required before coating the composition on the substrate.

[0129] The substrate is preferably as described above.

[0130] The component therefore preferably comprises the assembly described above, ie substrate / single layer laminate.

[0131] In some embodiments, the component has piezoelectric functionality and takes part in the manufacture of a piezoelectric element or device, an electronic element or device, an energy storage device or device, a semiconductor element or device, an energy generating element or device, or a dielectric element or device, or a tactile element or device.

[0132] Piezoelectric and electroactive devices preferably have active or passive functionality.

[0133] Examples of piezoelectric elements or devices include piezoelectric transducers, piezoelectric sensors, piezoelectric actuators, and piezoelectric energy harvesters.

[0134] Examples of electronic elements or devices include capacitors, microelectromechanical system elements, flexible electronics, printed circuit boards, integrated circuits, and haptic devices.

[0135] An example of a semiconductor element or device is a light emitting element.

[0136] Examples of energy storage elements or devices include electrodes, especially flexible electrodes.

[0137] Examples of energy generating elements or devices include photoelectric conversion elements, piezoelectric elements, thermoelectric conversion elements, actuators for micro / nano machines, and solar cells.

[0138] The invention also relates to a device including the above-mentioned component.

[0139] In some embodiments, the device is a transducer, a sensor, an actuator, a medical device such as a pacemaker, a tactile sensor for defect inspection or disease diagnosis / treatment, a strain resistant material such as a building, a bridge, a dam, an aircraft or space equipment, a broadcasting equipment, a wireless mobile device, a mobile communication device, a radar, a high speed information processing device, a display device, a probe.

[0140] The present invention also relates to the use of a vinyl polymer consisting of carbon and hydrogen atoms, and optionally oxygen and / or nitrogen atoms, and a silicon-sulfur compound to improve the adhesive strength of a fluoropolymer to a substrate, preferably a metal surface of the substrate.

[0141] The present invention also relates to a method for improving the adhesive strength of a fluoropolymer to a substrate by adding a vinyl polymer consisting of carbon and hydrogen atoms, and optionally oxygen and / or nitrogen atoms, and a silicon-sulfur compound to a composition comprising the fluoropolymer, and applying the composition onto the substrate.

[0142] In particular, the adhesive strength of the fluoropolymer is improved in aqueous solutions, and in particular when in contact with water, moisture, sweat, saliva, or any type of body fluid.

[0143] The fluoropolymer, vinyl polymer, silicon-sulfur compound, and substrate are as described above according to any of the embodiments.

[0144] The present invention also relates to the use of a monolayer according to the invention as a dielectric insulating layer.

[0145] The invention also relates to the use of a monolayer according to the invention as a piezoelectric layer.

[0146] The present invention also relates to the use of a monolayer according to the invention as an electroactive layer.

[0147] The present invention also relates to the use of a monolayer according to the invention as a pyroelectric layer.

[0148] The following examples illustrate the present invention without, however, limiting it. [Example]

[0149] On a laboratory scale, several monolayers with different compositions were prepared according to the following protocol (each step is carried out at room temperature):

[0150] 1 / Weigh out the solvent into a vial. 2 / The fluoropolymer is weighed into the same vial and the mixture is stirred for 30 minutes and then allowed to stand for 1 hour. 3 / The silicon-sulfur compound and the vinyl polymer are weighed and introduced into a vial. The mixture is then stirred for 10 minutes and then left to stand until all air bubbles have disappeared. The total content of "active ingredients" (fluoropolymer, silicon-sulfur compound and vinyl polymer) is 15% by weight.

[0151] Each composition is then applied by screen printing onto a metallized substrate and the solvent is evaporated by heating.

[0152] The adhesion of each layer was evaluated using cellophane tape according to the following protocol: Tape type: 3M2525 Adhesion strength to steel: 75N / 100mm Process: 1 / Cut a piece of adhesive tape about 3cm long and fold one end over. 2 / Apply adhesive tape to the sample by applying controlled and uniform pressure (finger pressure) to its surface. 3 / Using moderate, consistent pressure (by hand), peel off the adhesive tape at a 180° angle. 4 / Visually inspect the test area on the sample to identify any delamination of the film on the substrate. Scoring criteria: 5: No delamination, all layers are still intact on the substrate 4: Less than 5% of the layers (surface) were delaminated over the area where the tape was applied 3: Between 5% and 15% of the layers (surface area) were delaminated over the area where the tape was applied. 2: Between 15% and 35% of the layers (surface) were delaminated over the area where the tape was applied. 1: Between 35% and 65% of the layers (surface area) were delaminated over the area where the tape was applied 0: More than 65% of the layers (on the surface) were delaminated over the area where the tape was applied

[0153] Measurement of the adhesive strength level of each monolayer after immersion in aqueous solution was also evaluated according to the following protocol: Immersion delay: 3 days, 7 days, 10 days, 14 days Process: 1 / Prepare a tank of aqueous solution. 2 / Immerse each sample completely in the aqueous solution, carefully avoiding contact or rubbing against the layer (which could cause damage). 3 / Close the container to prevent evaporation of the solution. 4 / Remove the sample after x days of immersion. 5 / Carefully dab the layer with a lint-free cloth to remove any remaining aqueous solution, ensuring the layer is preserved and allowed to dry. 6 / Carry out a peel test using the procedures and criteria specified above.

[0154] The details of the composition of each layer and the results of the tests carried out on each layer are summarized in the table below (the vinyl polymer content and adhesion promoter content are calculated relative to the mass of the fluoropolymer):

[0155] [Table 1]

[0156] [ka]

[0157] Pentaerythritol tetrakis(3-mercaptopropionate): [ka]

[0158] These results show that the presence of both an adhesion promoter and a vinyl polymer is essential to obtain a fluoropolymer layer that exhibits high adhesive performance even after 14 days of immersion in aqueous solution.

[0159] They also show that the silicon-free thio compounds are not efficient in obtaining fluoropolymer layers that exhibit high adhesive performance even after 14 days of immersion in aqueous solution.

[0160] The dielectric properties of the adhesion-improved layer were compared to one of a single layer of fluoropolymer. Test samples were prepared according to the following protocol: 1. A polymer layer was coated onto a metal foil and cured as described above. 2. A mask containing several circular holes was placed on top of the polymer film. 3. The stack was placed inside a metallizer where evaporated gold was applied onto the film not covered by the mask, allowing the creation of conductive pads of defined surface area. 4. The actual surface of each pad was then measured under a microscope. 5. The capacitance C and dissipation factor tan δ of each pad at different frequencies (1, 10, 50 and 100 kHz) were determined using a GWIntek LCR-819 instrument (see Figure 1).

[0161] The dielectric constant, ε, indicates the tendency of a material to store electrical energy in an electric field. It essentially defines how a material responds to an electric field and describes the polarizability of a dielectric material: a material with a high dielectric constant will polarize more in response to an applied electric field than a material with a low dielectric constant, thereby storing more energy in the material. It is a fundamental property of electromagnetism and plays an important role in designing capacitors, insulators, and other electronic devices.

[0162] The loss factor tan δ quantifies the energy loss in a dielectric material when subjected to an AC electric field. It represents the energy loss due to dissipative effects within the material, such as dielectric conductivity and dipole orientation.

[0163] Relative permittivity ε r was calculated by the following formula:

[0164]

number

[0165] where C = capacitance, t = film thickness, and A s = surface area of ​​the pad, and ε0 = permittivity of vacuum.

[0166] Each measurement was repeated 15 to 18 times and the average values ​​of the dielectric constant and loss factor were calculated. The results are summarized in the table below showing the average values:

[0167] [Table 2]

[0168] These results show that all of these layers, whether containing fluoropolymer alone, or a mixture of fluoropolymer and silicon-sulfur compound, or a mixture of fluoropolymer, silicon-sulfur compound, and vinyl compound, have remarkably the same dielectric properties. Surprisingly, the presence of the silicon-sulfur compound and vinyl compound does not change the dielectric properties of the fluoropolymer, despite the fact that they have no dielectric properties of their own.

[0169] These results indicate that the adhesion promoter not only provides better adhesion and avoids delamination after water immersion, but also limits the decrease in dielectric constant.

[0170] Such monolayers can therefore withstand humidity, submersion, or contact with other liquids and still perform a response in electronic applications such as actuators (devices that convert electrical energy into mechanical motion), sensors (devices that sense changes in the environment and convert them into electrical signals), or energy storage (electrodes and membranes in batteries and supercapacitors).

Claims

1. a fluoropolymer; a silicon-sulfur compound, vinyl polymers consisting of carbon and hydrogen atoms, and optionally oxygen and / or nitrogen atoms; Including, single layer.

2. The fluoropolymer has formula (I): C(X 1 )(X 2 )=C(X 3 )(X 4 ) (I) (In the formula, X 1 , X 2 , X 3 and X 4 are each independently selected from H, Cl, Br, F, I, and optionally partially or fully halogenated C1-C6 straight or branched alkyl groups, with the proviso that X 1 , X 2 , X 3 and X 4 provided that at least one of the groups contains at least one fluorine atom.

2. The monolayer of claim 1, comprising units derived from a fluoromonomer of

3. the fluoropolymer is a terpolymer of vinylidene fluoride, a second fluoromonomer, and a third fluoromonomer, with the proviso that the second and third fluoromonomers are different from vinylidene fluoride and different from each other; The second and third fluoromonomers are represented by formula (I): C(X 1 )(X 2 )=C(X 3 )(X 4 ) (I) (In the formula, X 1 , X 2 , X 3 and X 4 are each independently selected from H, Cl, Br, F, I, and optionally partially or fully halogenated C1-C6 linear or branched alkyl groups, with the proviso that X 1 , X 2 , X 3 and X 4 provided that at least one of the groups contains at least one fluorine atom.

2. The monolayer of claim 1, having:

4. 2. The monolayer according to claim 1, wherein the fluoropolymer content is between 80% and 99.9% by weight relative to the total weight of the monolayer.

5. The silicon-sulfur compound has the formula (II): (Rd)S-Rw-Si(Ra)(Rb)(Rc) (II) wherein Rw is a linear, branched or cyclic group containing 1 to 18 carbon atoms and optionally one or several oxygen and / or nitrogen atoms; Ra, Rb and Rc are each independently selected from H, OH, Alk and -O-Alk, where Alk is a C1-C8 linear or branched alkyl group; and Rd is selected from the group consisting of H and an organic moiety containing 1 to 30 carbon atoms and at least one nitrogen and / or at least one oxygen atom.

2. The monolayer of claim 1, having:

6. 2. The monolayer according to claim 1, wherein the content of said silicon-sulfur compound is between 0.05% and 10% by weight relative to the total weight of said monolayer.

7. The vinyl polymer has the formula: C(X)(X') =C(X'')(X'') wherein X, X', X'' and X''' are independently selected from the group consisting of a hydrogen atom, an OH group, a COOH group, a CN group, an aromatic group, a saturated or unsaturated hydrocarbon group containing from 1 to 10 carbon atoms, and the aromatic or hydrocarbon group may optionally further contain an OH group, an ester group, a carboxyl group, an amine group, a nitrile group, and / or an amide group.

2. The monolayer of claim 1, comprising units derived from vinyl monomers of the formula:

8. The vinyl polymer has the formula (III): 【Chemistry 1】 wherein Xa and Xb are independently selected from H, a -CN group, and a C1-C8 linear, branched, or cyclic, saturated or unsaturated group containing 1 to 8 carbon atoms; and Xc is selected from H, a benzyl group, and a linear, branched, or cyclic, saturated or unsaturated aliphatic or aromatic group containing 1 to 24 carbon atoms, optionally substituted with at least one OH group and / or one COOH group and / or optionally interrupted by at least one -O- atom.

2. The monolayer of claim 1, which is an acrylate polymer comprising units derived from an acrylate monomer of formula:

9. 2. The monolayer according to claim 1, wherein the vinyl polymer content is between 0.05% and 10.0% by weight relative to the total weight of the monolayer.

10. 10. The monolayer of claim 1 having a thickness between 0.1 μm and 50 μm.

11. 10. The monolayer of claim 1, wherein the combined weight of the fluoropolymer, the silicon-sulfur compound, and the vinyl polymer in the monolayer accounts for more than 80% by weight of the total weight of the monolayer.

12. 12. An assembly comprising a substrate and a monolayer according to any one of claims 1 to 11, An assembly wherein the monolayer is applied to and in contact with at least one surface of the substrate or a portion of a surface of the substrate.

13. the substrate comprises a metal surface; 13. The assembly of claim 12, wherein the monolayer is applied onto and in contact with the metal surface.

14. The assembly of claim 12 , wherein the substrate comprises a gold surface.

15. The assembly of claim 12 , wherein the substrate comprises a copper surface.

16. 12. A method for producing a monolayer according to any one of claims 1 to 11, comprising the step of applying onto a substrate a composition comprising at least a fluoropolymer, a silicon-sulfur compound, and a vinyl polymer.

17. 12. A component comprising a monolayer according to any one of claims 1 to 11 coated on a substrate.

18. A device comprising the component of claim 17.

19. The use of a vinyl polymer consisting of carbon and hydrogen atoms, and optionally oxygen and / or nitrogen atoms, and a silicon-sulfur compound to improve the adhesive strength of a fluoropolymer to a substrate.

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