Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
  • H10K85/10—Organic polymers or oligomers
  • H10K85/141—Organic polymers or oligomers comprising aliphatic or olefinic chains, e.g. poly N-vinylcarbazol, PVC or PTFE
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
  • C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L27/12—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
  • C08L27/16—Homopolymers or copolymers or vinylidene fluoride
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
  • C08L33/10—Homopolymers or copolymers of methacrylic acid esters
  • C08L33/12—Homopolymers or copolymers of methyl methacrylate
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K10/00—Organic devices specially adapted for rectifying, amplifying, oscillating or switching; Organic capacitors or resistors having potential barriers
  • H10K10/40—Organic transistors
  • H10K10/46—Field-effect transistors, e.g. organic thin-film transistors [OTFT]
  • H10K10/462—Insulated gate field-effect transistors [IGFETs]
  • H10K10/468—Insulated gate field-effect transistors [IGFETs] characterised by the gate dielectrics
  • H10K10/471—Insulated gate field-effect transistors [IGFETs] characterised by the gate dielectrics the gate dielectric comprising only organic materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
  • H10K85/10—Organic polymers or oligomers
  • H10K85/151—Copolymers
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N30/00—Piezoelectric or electrostrictive devices
  • H10N30/80—Constructional details
  • H10N30/85—Piezoelectric or electrostrictive active materials
  • H10N30/857—Macromolecular compositions
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2327/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers
  • C08J2327/02—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment
  • C08J2327/12—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
  • C08J2327/16—Homopolymers or copolymers of vinylidene fluoride
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2427/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers
  • C08J2427/02—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment
  • C08J2427/12—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
  • C08J2427/16—Homopolymers or copolymers of vinylidene fluoride
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2433/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
  • C08J2433/04—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters
  • C08J2433/06—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters of esters containing only carbon, hydrogen, and oxygen, the oxygen atom being present only as part of the carboxyl radical
  • C08J2433/10—Homopolymers or copolymers of methacrylic acid esters
  • C08J2433/12—Homopolymers or copolymers of methyl methacrylate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/16—Applications used for films
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/20—Applications use in electrical or conductive gadgets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
  • C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates to a composition comprising a blend of electroactive fluorinated polymers and having a more stable dielectric permittivity over the range of temperature of use relative to each polymer employed alone.
• the invention also relates to formulations and films made from said composition.
• the invention also relates to a field effect transistor of which at least a portion of the dielectric layer is composed of a mixture of electroactive fluorinated polymers.
• the invention relates to an electronic (opto) device of which at least one layer or film is composed of a mixture of ferroelectric fluorinated polymers with a dielectric permittivity considered stable over the temperature range of use.
• Electroactive polymers are among the most promising materials for organic electronics. Electroactive polymers are polymers capable of converting mechanical or thermal energy into electricity or vice versa. Among these materials are fluorinated copolymers based on vinylidene fluoride (VDF) and trifluoroethylene (TrFE).
• VDF vinylidene fluoride
• TrFE trifluoroethylene
• PFEAs electroactive fluorinated polymers
• VDF-TrFE-Y certain P-type terpolymers with Y are preferably chlorotrifluoroethylene (CTFE) or chlorofluoroethylene (CFE); are ferroelectric PFEAs relaxers.
• CFE chlorotrifluoroethylene
• CFE chlorofluoroethylene
• a high dielectric permittivity allows the use of these polymers in the manufacture of devices for electronics, in particular organic electronics and more particularly field effect transistors. Indeed, the use of high dielectric permittivity polymers reduces the power consumption of the transistors by reducing the voltage to be applied to the gate ("gate" in English) necessary to make conductive the semiconductor layer.
• the dielectric permittivity of a PFEA varies as a function of temperature and is maximum at a temperature commonly referred to as "Curie temperature (Te)".
• Te urie temperature
• the Te is independent of the frequency of the electric field.
• the Te varies as a function of the frequency of the electric field.
• the maximum dielectric permittivity can reach or even exceed 30 at the Te.
• the Te varies between 15 and 140 ° C depending on the composition of the PFEAs (VDF / TrFE ratio and Y termonomer ratio).
• Dielectric permittivity variations affect the performance of electroactive devices. Indeed, many properties such as polarization and deformation are directly related to the permittivity.
• electroactive devices are integrated with non-temperature-controlled electronic equipment. In order to maintain constant properties, systems must be developed to compensate for these variations. These often complex and expensive systems limit the use of PFEAs in some electronic equipment. Maintaining a high and constant dielectric permittivity over a wider temperature range is necessary to promote the development of electroactive devices. In a particular case of electroactive device, the development of field effect transistors containing a dielectric layer with high permittivity requires stable temperature properties to ensure the proper operation of the device.
• EP 0206926 discloses mixtures of ferroelectric polymers with different Curie temperatures, these alloys aimed at optimizing the dielectric properties over a wide range of temperatures and frequencies.
• the mixture of a terpolymer P (VDF-TrFE-CTFE), containing 10 mole percent of CTFE, with a copolymer P (VDF-TrFE), of molar composition VDF-TrFE 60-40, (alloy I, corresponding to the curve 18 of FIG. 7) makes it possible to obtain a material with a relative dielectric constant of between 20 and 30 for a range of temperatures ranging from 20 to 100 ° C. and whose maximum is around 80 ° C.
• the invention also aims at providing field effect transistors having a dielectric layer consisting of a mixture of electroactive fluorinated polymers with high dielectric permittivity and stable over a wide temperature range.
• the optimization of the polymer mixture makes it possible to obtain a more stable dielectric permittivity, between 15 and 120 ° C., than that obtained for a single polymer.
• the invention firstly relates to a composition comprising a mixture of electroactive fluorinated polymers, said mixture being composed of: a) at least one fluorinated terpolymer of formula P (VDF-XY) comprising units derived from vinylidene fluoride (VDF) units derived from a monomer X selected from trifluoroethylene (TrFE), tetrafluoroethylene, chlorotrifluoroethylene (CTFE), vinyl fluoride, 1,1-chlorofluoroethylene, hexafluoropropene, 3,3,3-trifluoropropene 1,1,3,3,3-tetrafluoropropene, 2,3,3,3-tetrafluoropropene, 1-chloro-3,3,3-trifluoropropene and 2-chloro-3,3,3-trifluoropropene, and a third monomer Y, b) and at least one copolymer of formula P (VDF-TrFE) comprising units derived
• said composition comprises the following characters, where appropriate combined.
• the third monomer is chlorofluoro-1, 1-ethylene or chlorotrifluoroethylene.
• the proportion of units derived from the monomer Y is from 1 to 15 mol%, more preferably from 1 to 12 mol%, relative to all the units of said terpolymer.
• the fluorinated terpolymer (component a) and the fluorinated copolymer (component b) are present in a weight ratio of 50:50 to 99: 1, preferably 55:45 to 99: 1, more preferably particularly preferred 60:40 to 95: 5.
• the composition according to the invention further comprises up to 2% by weight of an additive, said additive being a (meth) acrylic polymer, in particular poly (methyl methacrylate).
• the invention also relates to a formulation (or ink) made from the fluoropolymer mixture described above, in solution in a solvent.
• Another subject of the invention is a film or polymer layer made from said formulation.
• This layer has a more stable dielectric permittivity over the operating temperature range compared to an electroactive fluoropolymer used alone.
• the invention also relates to an electronic (opto) device comprising a substrate, and a film prepared from the formulation described above disposed thereon.
• the device further comprises electrodes on either side of the film, said device preferably being an actuator.
• the invention also relates to an organic field-effect transistor comprising a semiconductor element, electrodes and a dielectric layer with a high temperature-stable dielectric permittivity.
• the dielectric layer is composed at least in part of a mixture of electroactive fluorinated polymers.
• said mixture of electroactive fluorinated polymers is composed of:
• At least one electroactive fluorinated terpolymer of formula P (VDF-X-Y) comprising units derived from vinylidene fluoride (VDF), units derived from a monomer X chosen from trifluoroethylene
• TRFE tetrafluoroethylene
• CTE chlorotrifluoroethylene
• vinyl fluoride 1,1-chlorofluoroethylene, hexafluoropropene, 3,3,3-trifluoropropene, 1,3,3,3-tetrafluoropropene, 2,3,3,3-tetrafluoropropene, 1-chloro-3,3,3-trifluoropropene and 2-chloro-3,3,3-trifluoropropene, and a third monomer Y,
• VDF-TrFE formula P (VDF-TrFE) comprising units derived from vinylidene fluoride and units derived from trifluoroethylene.
• the dielectric layer is composed at least in part of the composition according to the invention described above.
• the present invention overcomes the disadvantages of the state of the art.
• it provides a composition having a high and constant dielectric permittivity over a wider temperature range. This is accomplished by the combination of an electroactive fluorinated terpolymer and a copolymer compatible with the terpolymer having a Curie temperature different from that of the terpolymer.
• Figure 1 shows the block diagram of a field effect transistor.
• the elements 1 represent the three electrodes: source, grid ("spoil") and drain.
• Element 2 represents the dielectric layer which is in the invention composed of at least one layer made from a mixture of electroactive fluorinated polymer with high dielectric permittivity.
• Element 3 is the semiconductor.
• FIG. 2 is a graph illustrating relative permittivity curves (y-axis), measured at 1 kHz, as a function of the temperature (abscissa axis) (rise and fall) of three electro-active fluorinated polymers: P (VDF-TrFE- CTFE) (dash-dashed curve), P (VDF-TrFE-CTFE) (solid curve) and P (VDF-TrFE) (dashed curve).
• the VDF / TrFE / Y molar compositions of the polymers are: 60/30/10, 61/35/4, 70/30, respectively.
• FIG. 3 is a graph illustrating relative permittivity curves (ordinate axis), measured at 1 kHz, as a function of the temperature (abscissa axis) (rise and fall) of an electroactive fluorinated copolymer P (VDF-TrFE) of molar composition 43/57.
• FIG. 4 is a graph illustrating relative permittivity curves (ordinate axis), measured at 1 kHz, as a function of temperature (abscissa axis) (climb only shown) of 4 compositions: (i) broken black line, terpolymer P (VDF-TrFE-CFE) containing 6.9 mol% CFE, (ii) broken line gray, terpolymer P (VDF-TrFE-CFE) with 8.2 mol% CFE, (iii) solid gray line, mixture 70-30 mass of the terpolymer (ii) with a copolymer P (VDF-TrFE) of molar composition 54/46; and (iv) black solid line, 70-30 mass blend of the terpolymer (i) with a P (VDF-TrFE) copolymer of molar composition 54/46.
• Figure 5A is a graph illustrating relative permittivity curves (ordinate axis), as a function of temperature (abscissa) (rise and fall) and as a function of the frequency of the electric field (0.1 - 1 - 10 - 100 kHz), a mixture 90-10 by weight of a terpolymer P (VDF-TrFE-CFE) containing 6.9 mol% of CFE and a copolymer P (VDF-TrFE) of molar composition 54 / 46.
• VDF-TrFE-CFE terpolymer P
• VDF-TrFE copolymer P
• FIG. 6 is a graph illustrating the relative permittivity curve (ordinate axis), measured at 1 kHz, as a function of the temperature (abscissa axis) (rise and fall) of a 50-50 mass mixture of a P (VDF-TrFE) copolymer of molar composition 43/57 with a P terpolymer (VDF-TrFE-CFE) containing 8.2 mol% of CFE.
• the invention is based firstly on the use of a fluorinated terpolymer (component a).
• fluorinated is meant a terpolymer having -F groups.
• the fluorinated terpolymer is a relaxor ferroelectric polymer.
• a relaxor ferroelectric polymer has a weak coercive field (typically less than 10 V / ⁇ ), a low remanent polarization (typically less than 10 mC / m 2 ) or even zero, and a maximum of dielectric permittivity as a function of the frequency-dependent temperature. on electric field.
• the terpolymer, of formula P comprises units derived from vinylidene fluoride (VDF), units derived from a monomer X selected from trifluoroethylene (TrFE), tetrafluoroethylene, chlorotrifluoroethylene (CTFE), vinyl fluoride, 1,1-chlorofluorethylene (CFE), hexafluoropropene, 3,3,3-trifluoropropene, 1,3,3,3-tetrafluoropropene, 2,3,3,3-tetrafluoropropene, 1-chloro-3,3,3-trifluoropropene and 2-chloro-3,3,3-trifluoropropene, and a third monomer Y.
• VDF vinylidene fluoride
• a monomer X selected from trifluoroethylene (TrFE), tetrafluoroethylene, chlorotrifluoroethylene (CTFE), vinyl fluoride, 1,1-chlorofluorethylene (CFE), hex
• the monomer X is TrFE.
• Y represents units derived from CFE (1-chloro
• the third monomer can in particular be chosen from halogenated alkenes, in particular halogenated propenes or ethenes, and for example from tetrafluoropropenes (especially 2,3,3,3-tetrafluoropropene), chlorotrifluoropropenes (especially 2-chloro-3,3,3-trifluoropropene), 1-chloro-2-fluoroethylene and trifluoropropenes (especially 3,3,3-trifluoropropene), pentafluoropropenes (especially 1,1,3,3,3-pentafluoropropene or 1,2,3,3,3-pentafluoropropene), 1-chloro-2,2- difluoroethylene, 1-chloro, 2-fluoroethylene, 1-bromo-2,2-difluoroethylene, bromotrifluoroethylene, fluoroethylene (or vinyl fluoride), tetrafluoroethylene and hexafluoropropene.
• the third monomer may also be a perfluoroalkylvinylether, of general formula Rf-O-CF-CF2, Rf being an alkyl group, preferably C1 to C4.
• Rf being an alkyl group, preferably C1 to C4.
• Preferred examples are PPVE (perfluoropropylvinylether) and PMVE (perfluoromethylvinylether).
• the terpolymers of the invention may be produced using any known method, such as emulsion polymerization, microemulsion polymerization, suspension polymerization and solution polymerization.
• emulsion polymerization microemulsion polymerization
• suspension polymerization suspension polymerization
• solution polymerization solution polymerization.
• the use of the method described in WO 2010/1 16105 is particularly preferred. This process makes it possible to obtain polymers of high molecular weight and suitable structuring.
• the molar proportion of Y units in the terpolymer is from 1 to 15%, preferably from 1 to 12%.
• the molar ratio of the VDF units on the TrFE units in the terpolymer is from 85/15 to 30/70, and preferably from 75/25 to 40/60.
• the weight average molecular weight which in the context of this application is also referred to as "molecular weight" (Mw), of the terpolymer, is from 200,000 to 1,500,000 g / mol, preferably from 250,000 to 1,000,000 g / mol, and more particularly 300,000 to 700,000 g / mol.
• the latter can be adjusted by modifying certain 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) in 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 performed with polystyrene standards.
• the sample is dissolved in 0.5 g / l in DMF and filtered through a 0.45 ⁇ m nylon filter.
• the molecular weight can also be evaluated by measuring the melt index at 230 ° C under a load of 5 kg according to ASTM D1238 (ISO 1133).
• the molecular weight can also be characterized by a measurement of the viscosity in solution according to ISO 1628.
• Methyl ethyl ketone (MEK) is a preferred solvent for terpolymers for the determination of the viscosity index.
• the molar composition of the terpolymers of the invention can be determined by various means.
• Multi-core NMR techniques in this case proton ( 1 H) and fluorine ( 19 F), can also be carried out 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 various monomers are then identified in the spectra produced according to one or the other nucleus.
• the TrFE unit CF2 gives proton NMR a specific signal characteristic of the CFH group (at about 5 ppm). It is the same for the VDF Ch groups (massive centered at 3 ppm).
• the relative integration of the two signals gives the relative abundance of the two monomers, i.e. the VDF / TrFE molar ratio.
• the invention is then based on the use of a copolymer (component b) of formula P (VDF-TrFE) comprising units derived from vinylidene fluoride and units derived from trifluoroethylene, compatible with the terpolymer and having a Curie temperature. different from that of the terpolymer.
• a copolymer component b) of formula P (VDF-TrFE) comprising units derived from vinylidene fluoride and units derived from trifluoroethylene, compatible with the terpolymer and having a Curie temperature. different from that of the terpolymer.
• ком ⁇ онент is meant that the mixture of the two polymers forms a homogeneous phase with a single glass transition temperature.
• the proportion of units derived from trifluoroethylene is greater than 45 mol% relative to the sum of the units derived from vinylidene fluoride and trifluoroethylene, preferably greater than 50 mol%.
• the Curie temperature of the copolymer is between 20 and 80 ° C.
• the Curie temperature of the polymers of the invention can be measured by differential scanning calorimetry or by dielectric spectroscopy.
• composition according to the invention is a mixture of relaxor ferroelectric fluoropolymers comprising at least one fluorinated terpolymer (component a) and at least one copolymer P (VDF-TrFE) having a molar composition of TrFE greater than 45 mol% (component b) .
• the mass proportion of component b) is between 0.1 and 50%, preferably between 1 and 45%, advantageously between 5 and 40% of the total weight of the composition.
• the composition of the invention comprises at least one terpolymer as described above (optionally two or more thereof), and at least one copolymer as described above (optionally two or more thereof).
• the composition of the invention may also comprise an additive, whose role is to increase the dielectric permittivity.
• the composition comprises up to 2% by weight of an additive, said additive being a (meth) acrylic polymer, in particular poly (methyl methacrylate) (PMMA).
• Another subject of the invention consists of a formulation (or ink) based on electroactive fluorinated polymers comprising the composition described above, in solution in a solvent.
• said solvent is selected from dimethylformamide, dimethylacetamide, dimethylsulfoxide, ketones, especially acetone, methylethylketone, methylisobutylketone and cyclopentanone, furans, especially tetrahydrofuran; esters, in particular methyl acetate, ethyl acetate, propyl acetate, butyl acetate and propylene glycol methyl ether, carbonates, especially dimethyl carbonate, phosphates, especially triethylphosphate, and mixtures thereof.
• the solvent may be present in the formulation, in a mass proportion of at least 50%, preferably at least 80%.
• the formulation of the invention can be manufactured by dissolving its various compounds in a solvent.
• the electroactive fluorinated polymers can be dissolved simultaneously in the solvent, or one after the other, or separately and then formulations are mixed. It is preferred to dissolve the terpolymer in the solvent before the copolymer.
• the invention notably provides films made from formulations according to the invention and deposited on a substrate.
• the substrate may, for example, be a polymeric substrate, such as a substrate of polyethylene terephthalate or polyethylene naphthalate, or a substrate of paper, glass or silicon.
• the film is deposited in solvent or molten route; then dried (evaporation of the solvent) and annealed to improve its crystallinity (by heating at a temperature below the melting temperature and above the Curie temperature of the composition, for a period greater than or equal to 1 minute).
• the film according to the invention has a relative dielectric permittivity, referred to as stable, varying from +/- 10, preferably +/- 5, advantageously + 1-2 over a temperature range of between 0 and 100 ° C. preferably between 10-80 ° C and advantageously between 15-70 ° C.
• the dielectric permittivity measurement can be carried out by means of a LCF meter Sefelec LCR 819, which makes it possible to measure a capacitance which is proportional to the permittivity.
• This film is therefore suitable for the manufacture of electronic devices which require for their operation a stable permittivity over a wide range of temperatures.
• the invention therefore provides electronic devices comprising a substrate, and at least one film according to the invention.
• electronic device is intended to mean a single electronic component or a set of electronic components capable of performing one or more functions in an electronic circuit such as transistors (in particular with a field effect), chips, batteries, photovoltaic cells, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), sensors, actuators, transformers, haptic devices, electromechanical microsystems, electro-thermal devices and detectors.
• the electronic device is more particularly an optoelectronic device, that is to say capable of emitting, detecting or controlling electromagnetic radiation.
• the device comprises at least one composition film of the invention and electrodes on either side, and thus forms an actuator.
• Another subject of the invention relates to an organic field-effect transistor comprising (with reference to appended FIG. 1), a semiconductor element (3), electrodes (1) and a dielectric layer (2).
• the dielectric layer is composed at least in part of a mixture of electroactive fluorinated polymers.
• said mixture of electroactive fluorinated polymers is composed of: at least one electroactive fluorinated terpolymer of formula P (VDF-XY) comprising units derived from vinylidene fluoride (VDF), units derived from a monomer X chosen from trifluoroethylene (TrFE), tetrafluoroethylene, chlorotrifluoroethylene, (CTFE), vinyl fluoride, 1,1-chlorofluoroethylene, hexafluoropropene, 3,3,3-trifluoropropene, 1,3,3,3-tetrafluoropropene, 2,3,3,3-tetrafluoropropene 1-chloro-3,3,3-trifluoropropene and 2-chloro-3,3,3-trifluoropropene, and a third monomer Y,
• VDF-TrFE formula P (VDF-TrFE) comprising units derived from vinylidene fluoride and units derived from trifluoroethylene.
• the monomer X is preferably trifluoroethylene.
• the dielectric layer is composed at least in part of the composition according to the invention, in which the proportion of units derived from trifluoroethylene in copolymer b is greater than 45 mol%, preferably greater than 50. mol% relative to the sum of units derived from vinylidene fluoride and trifluoroethylene.
• a 7% by weight formulation in butan-2-one (methyl ethyl ketone, MEK) is produced by mixing the electroactive polymer (s) in a flask surmounted by a straight and heated condenser. at 80 ° C for 16 h. After complete dissolution, the solution is filtered at 1 ⁇ on a PTFE filter.
• a film of about 250 nm is made on a spin silicon substrate from the previously prepared formulation. It is then dried at 60 ° C for 5 min. The films obtained are then annealed at 115 ° C. for 2 hours. The upper gold electrode is deposited by evaporation under vacuum or by spraying.
• the dielectric properties of the films are measured by impedance spectroscopy.
• Figures 2 and 3 show a strong evolution of dielectric permittivity as a function of temperature.
• the hysteresis between rise and fall in temperature is clear.
• the copolymer P (VDF-TrFE) of molar composition 43/57 the hysteresis is negligible.
• the hysteresis observed for certain P (VDF-TrFE) copolymers is also measurable by differential scanning calorimetry which makes it possible to measure the Curie temperatures at the peak of the transition to heating and cooling.
• Table 1 contains the Curie temperature values measured at the peak of the DSC transition during the second and third cooling.
• the delta T is less than 2 ° C.
• the terpolymers alone have a dielectric permittivity that varies greatly with temperature.
• a dielectric permittivity stability is observed in the case of the mixtures studied with a copolymer rich in TrFE ( Figures 4 and 6). Addition of a copolymer does not reveal hysteresis in the mixture ( Figure 5). An increase in the dielectric permittivity is observed. This result is surprising and differs from the examples of the patent WO 2017/093145 where the addition of 3 or 6% of PMMA decreases the permittivity (Comparative Examples C2 and C3).

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• 2017
  • 2017-08-09 FR FR1757604A patent/FR3070042B1/fr active Active
• 2018
  • 2018-08-07 EP EP23194005.7A patent/EP4255162A3/fr not_active Withdrawn
  • 2018-08-07 JP JP2020507048A patent/JP7508365B2/ja active Active
  • 2018-08-07 KR KR1020237027970A patent/KR102759816B1/ko active Active
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