Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G41/00—Compounds of tungsten
  • C01G41/02—Oxides; Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/02—Printing inks
  • C09D11/03—Printing inks characterised by features other than the chemical nature of the binder
  • C09D11/037—Printing inks characterised by features other than the chemical nature of the binder characterised by the pigment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y40/00—Manufacture or treatment of nanostructures
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/01—Particle morphology depicted by an image
  • C01P2004/04—Particle morphology depicted by an image obtained by TEM, STEM, STM or AFM
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/30—Particle morphology extending in three dimensions
  • C01P2004/32—Spheres
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/80—Compositional purity

Definitions

• the present invention relates to a method of synthesizing nanoparticles
• the present invention also relates to the tungsten oxide nanoparticles which can be obtained from the claimed method of synthesis.
• the present invention relates to tungsten oxide nanoparticles formulated in a wide range of inks which can advantageously be used in numerous applications.
• Tungsten trioxide has a very wide range of potential applications by virtue of its very promising properties.
• a major drawback of the available synthesis methods lies in their inability to be able to prepare, by means of a single reproducible synthesis method, a tungsten trioxide having the morphology and the properties then allowing its use in a large number of the applications cited above. -above.
• One of the most widely used methods of synthesizing tungsten oxide consists in dissolving tungstic sodium Na2W04.2H20 in water and adding hydrochloric acid HCl to it until a gel is obtained, gel which is then dissolved in order to obtain a stabilized dispersion.
• This technique has the aforementioned drawbacks for various reasons, the difficulty of which we will cite as an example.
• the present invention aims to overcome one or more drawbacks of the prior art by providing an alternative synthesis method for preparing in a simple and reproducible tungsten trioxide nanoparticles which can be formulated in a large number of different inks allowing their use in a large number of applications.
• this objective is achieved by a method of synthesis of tungsten oxide nanoparticles comprising the following consecutive steps
• halogenated tungsten compound may advantageously be used in the context of the present invention, for example tungsten compounds comprising chlorine, bromine, iodine, fluorine atoms, and / or a mixture of two or more of these atoms, and optionally one or more oxygen atoms.
• tungsten (II) bromide tungsten (II) chloride, tungsten (II) iodide, tungsten (III) bromide, tungsten (III) chloride, tungsten (IV) tetrachloride, bromide tungsten (V), tungsten chloride (V), tungsten fluoride (V), tungsten oxytribromide (V), tungsten oxytrichloride (V), tungsten bromide (VI), tungsten chloride (VI), tungsten dioxydibromide (VI), tungsten dioxydichloride (VI), tungsten dioxydiiodide (VI), tungsten fluoride (VI), tungsten oxytetrabromide ( VI), tungsten oxytetrachloride (VI), tungsten oxytetrafluoride (VI), and tungsten halides
• Tungsten phexachloride Any source of tungsten hexaeze may advantageously be used in the context of the present invention. Commercial compounds with a degree of purity of more than 98% by weight, preferably more than 99% by weight of tungsten hexachloride will be favored. By way of illustration, the examples of the present invention were produced with a tungsten hexachloride (CAS number 13283-01-7) from Alfa Aesar with the following characteristics: 99%, formula WC16, molecular weight 396.57, under the powder form, melting point of 275 ° C, boiling point of 346 ° C and density of 3.52.
• glycols for example ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, 1, 3-butylene glycol, 1,2-
• Butylene glycol, 2,3-Butylene glycol, P entamethylene glycol, hexylene glycol,. ), and / or glycol ethers for example the glycol mono- or di-ethers among which we will mention, for example, ethylene glycol propyl ether, ethylene glycol butyl ether, ethylene glycol phenyl ether, propylene glycol phenyl ether , di ethylene glycol methyl ether, di ethylene glycol ethyl ether, di ethylene glycol propyl ether, di ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, propylene glycol propyl ether, ethylene glycol di-butyl ether, diethyl ether ethylene glycol, di butylene glycol diethyl ether, diglymes, ethyl diglyme, butyl diglyme), and or glycol ether acetates (e.
• a glycol is used as alcohol, for example ethylene glycol or, preferably, diethylene glycol. Any alcohol source may
• a mixture of two different (or more) alcohols can be used as solvent for the halogenated tungsten compound provided that one of the alcohols (preferably the one with the highest concentration in the mixture) meets the condition of standard boiling point greater than or equal to 120 ° C, preferably greater than or equal to 150 ° C; preferably, in the case of a mixture of alcohols, all the alcohols present will meet the condition of standard boiling temperature greater than or equal to 120 ° C., preferably greater than or equal to 150 ° C.
• a glycol for example an unsubstituted glycol, in particular ethylene glycol, preferably diethylene glycol; it preferably represents at least 90% by weight of the solvent used in step a), preferably at least 95%, at least 99%, and even 100% by weight.
• the solution obtained at the end of steps a) and b) is a clear blue solution.
• the solution obtained at the end of steps a) and b) is characterized by a molar ratio between the halogenated tungsten compound (for example tungsten hexachloride (WC16)) and alcohol (for example diethylene glycol) which is between 0.001 and 0.5, for example between 0.005 and 0.1, preferably between 0.010 and 0.025.
• a molar ratio between the halogenated tungsten compound for example tungsten hexachloride (WC16)
• alcohol for example diethylene glycol
• oxalic acid Any source of oxalic acid may advantageously be used in the context of the present invention. Commercial compounds with a degree of purity of more than 98% by weight, preferably more than 99% by weight of oxalic acid will be favored. Although this is not a preferred variant of the synthesis according to the present invention, oxalic acid di hydrate may also be used.
• the oxalic acid is first dissolved before its use in step c) above.
• this dissolution can advantageously be carried out in water.
• the temperature of the oxalic acid solution is controlled and / or heated so that this temperature is at least 25 ° C, preferably at least 40 ° C before its use in step c) above; this temperature will, for example, be less than 90 ° C., preferably less than 80 ° C.
• the oxalic acid before its use in step c), the oxalic acid is in the form of a clear colorless solution.
• the oxalic acid solution before its use in step c), is characterized by a molar ratio between oxalic acid and water which is between 0.0005 and 0.5, for example between 0.001 and 0.1, preferably between 0.005 and 0.020.
• step c) is characterized in that the coloring of the reaction medium turns to a dark blue color.
• step c) is characterized by a molar ratio between the halogenated tungsten compound (for example tungstenexachloride (WC16)) and the solvent (for example diethylene glycol and l water) which is between 0.0001 and 0.1, for example between 0.0005 and 0.030, preferably between 0.001 and 0.015; the said ratio corresponding to the number of moles of WC16 divided by the sum of the number of moles of diethylene glycol and the number of moles of water.
• a molar ratio between the halogenated tungsten compound for example tungstenexachloride (WC16)
• the solvent for example diethylene glycol and l water
• step c) is characterized by a molar ratio between oxalic acid and the solvent (preferably diethylene glycol and water) which is between 0 , 0005 and 0.2, for example between 0.001 and 0.05, preferably between 0.004 and 0.012; the said ratio corresponding to the number of moles of oxalic acid divided by the sum of the number of moles of diethylene glycol and the number of moles of water.
• solvent preferably diethylene glycol and water
• step c) is characterized by a molar ratio between tungsten hexaehloride (WC16) and oxalic acid of between 0.25 and 0.75, for example between 0.4 and 0.6, preferably between 0.45 and 0.55.
• WC16 tungsten hexaehloride
• oxalic acid between 0.25 and 0.75, for example between 0.4 and 0.6, preferably between 0.45 and 0.55.
• tungsten oxide nanoparticles comprising oxalic acid ligands which it was not possible to obtain with existing synthesis methods.
• These new nanoparticles are characterized by a higher morphology and higher content of oxalic acid ligands.
• the Applicant thinks that it is the combination of the synthesis steps as defined above and, in particular, the control of the temperature variation and of the oxalic acid concentration during steps c) and d) which made it possible to obtain the versatile nanoparticles, namely nanoparticles having different morphologies and contents of oxalic acid ligands.
• the present invention also relates to a use of the claimed method of synthesis for the production of tungsten oxide nanoparticles of morphologies and of oxalic acid ligand contents controlled by the variation in temperature and in the oxalic acid concentration during the steps c) and d) the synthesis method; which makes these nanoparticles universal, that is to say formulated in inks intended for different applications.
• the Applicant has also discovered that the tungsten oxide nanoparticles thus obtained could be formulated in a large number of different inks which thus allows their use in a large number of applications.
• This wide possibility of uses and applications as an ink also seems permitted thanks to the maintenance of a liquid phase during the synthesis of tungsten oxide nanoparticles until the formulation of inks comprising said nanoparticles and their end use.
• a liquid phase is always present during the stages of preparation of the tungsten oxide nanoparticles, as well as during all the stages (for example the washing and purification steps mentioned below) which precede the addition of other compounds used for the formulations inks.
• tungsten oxide nanoparticles are never isolated and dried before their final use as ink; they therefore preferably always remain in contact with a liquid phase (for example a solvent) in which they are dispersed. This approach also removes any step
• tungsten oxide nanoparticles obtained in step e) of the claimed method are subjected to a washing which makes it possible to remove all that is not chemically or physically linked to the nanoparticles.
• This washing is carried out preferably with G alcohol; by way of illustration, an aliphatic monohydric alcohol can be used which is preferably selected from the group consisting of ethanol, propanol, butanol, pentanol and hexanol as well as their isomers (for example isopropanol, n-butanol, tert-butanol ), and / or a mixture of two or more of said aliphatic monohydric alcohols.
• Ethanol is the preferred alcohol and the tungsten oxide nanoparticles are then preferably stored in ethanol. Washing can also advantageously be carried out by centrifugation and / or gravitational settling.
• the final solution obtained is preferably characterized by a concentration greater than 25 mg / g of W03-x.xH20 in ethanol, for example greater than 50 mg / g of W03-x.xH20 in ethanol.
• This solution is preferably dark blue and can be stored for example in the fridge at temperatures between 2 ° C and 10 ° C, for example between 3 ° C and 5 ° C.
• the present invention therefore makes it possible to obtain nanoparticles of oxide of
• tungsten comprising small oxalic acid ligands.
• These nanoparticles can be of various and varied forms; by way of illustration, mention will be made of beads (for example from 1 to 100 nm), rods (for example of length L ⁇ 200 to 300 nm), wires (for example of lengths having a few hundred nanometers or even a few microns), discs, stars, pyramids, tetrapods or crystals when they do not have a predefined shape.
• the nanoparticles have dimensions between 1 and 50 nm, preferably between 2 and 20 nm;
• the Applicant has even managed to repeatedly and constantly produce nanoparticles whose dimensions are less than 1 Onm, which constitutes a considerable advance in this field.
• the claimed method of synthesis has made it possible to obtain nanoparticles of spheroidal and / or spherical shape.
• the term "of spheroidal shape” means that the shape resembles that of a sphere but it is not perfectly round (“quasi-spherical”), for example an ellipsoidal shape.
• the nanoparticles can advantageously be identified by means of photographs taken by microscope, in particular by means of a device of the type Transmission electron microscope (TEM) from Thermofisher Scientific in accordance with the indications described in the example below.
• TEM Transmission electron microscope
• the nanoparticles are spheroidal and are preferably characterized by means of this TEM identification by an average area of nanoparticles of between 1 and 20 nm2, preferably between 5 and 15 nm2, and / or by an average nanoparticle perimeter of between 3 and 20 nm, preferably between 5 and 15 nm, and / or an average nanoparticle diameter of between 0.5 and 7 nm, preferably between 1 and 5 nm.
• the nanoparticles are spheroidal and characterized alternatively by means of a device of the Nanosizer S type from Malvem in accordance with the indications described in the example below with D50 values between 1 and 50 nm, preferably between 2 and 20 nm, for example less than 10 nm. D50 is the diameter for which 50% of the nanoparticles by number are smaller.
• a particular example of synthesis of nanoparticles according to the present invention is described by way of illustration below: a mixture is carried out in a container with magnetic stirring at 80 ° C of tungsten hexachloride and diethylene glycol until obtaining a clear blue solution.
• oxalic acid is dissolved in magnetic stirring at room temperature in water until a clear, colorless solution is obtained.
• the aqueous oxalic acid solution is then added to the tungsten hexachloride solution at 80 ° C with magnetic stirring. Once the addition is complete, the temperature of the reaction medium is increased to 111 ° C. and the mixture is left under stirring for 3 h which allows (after decantation and washing) to obtain the nanoparticles of tungsten trioxide.
• This synthesis makes it possible to obtain nano spheres of tungsten trioxide with a distribution of particle sizes well controlled.
• the tungsten oxide nanoparticles comprising oxalic acid ligands thus obtained can thus be advantageously formulated in many different inks making it possible to meet diverse and varied applications.
• An additional advantage of the nanoparticles according to the present invention lies in the fact that their preparation can be carried out under non-binding pressure conditions, for example at pressure conditions close to or identical to normal or ambient conditions. It is better to stay at values located at less than 40% of the values of normal or ambient pressure conditions.
• the Applicant has found that it was preferable to maintain the pressure conditions during the preparation of the nanoparticles (and optionally inks) at values oscillating at most 30%, preferably 15% around the values of normal conditions or ambient. Control of these pressure conditions can therefore advantageously be included in the preparation device so as to fulfill these conditions.
• the ink formulated based on the nanoparticles according to the present invention can advantageously be used in any printing method, in particular in the following printing methods: jet d '' ink, spray, doctor blade, spin coating, and slot die coating.
• the present invention therefore also relates to a use of said inks in the so-called “security” fields, photovoltaics, sensors (for example gas sensors), touch screens, biosensors, and technologies without contact (“contactless technologies”).
• nanoparticles of W03 were obtained by following the specific synthetic example described in the text above. They were stored in ethanol as described in the description above.
• TGA thermogravimetric
• The% of organic phase is between 10 and 15%.
• the table below shows the ink compositions (formulated from the same nanoparticles of W03) which are particularly suitable for the fields of electronics.
• the additive is a rheology modifying agent selected from rheology modifying agents of the cellulosic type.
• the constituents are indicated in the table as well as their concentration by weight for each of the compositions.
• hydrodynamic diameter The values of hydrodynamic diameter and D50 are given in the table below.
• the inks are particularly suitable for the following printing modes and type of OPV structures:

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)

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• 2018
  • 2018-12-13 FR FR1872893A patent/FR3089969B1/fr not_active Expired - Fee Related
• 2019
  • 2019-12-03 TW TW108144146A patent/TW202031595A/zh unknown
  • 2019-12-04 JP JP2021533573A patent/JP2022512415A/ja active Pending
  • 2019-12-04 US US17/309,622 patent/US20220024780A1/en not_active Abandoned
  • 2019-12-04 EP EP19812799.5A patent/EP3894356A1/de not_active Withdrawn
  • 2019-12-04 KR KR1020217021364A patent/KR20210100164A/ko not_active Withdrawn
  • 2019-12-04 WO PCT/EP2019/083640 patent/WO2020120250A1/fr not_active Ceased
  • 2019-12-04 CN CN201980082915.2A patent/CN113454030A/zh active Pending
  • 2019-12-04 SG SG11202106154SA patent/SG11202106154SA/en unknown

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