WO2012033975A1 - Fluides caloporteurs comprenant des nanomatériaux et leurs procédés de préparation et d'utilisation - Google Patents

Fluides caloporteurs comprenant des nanomatériaux et leurs procédés de préparation et d'utilisation Download PDF

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WO2012033975A1
WO2012033975A1 PCT/US2011/050929 US2011050929W WO2012033975A1 WO 2012033975 A1 WO2012033975 A1 WO 2012033975A1 US 2011050929 W US2011050929 W US 2011050929W WO 2012033975 A1 WO2012033975 A1 WO 2012033975A1
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fluid composition
particles
dimension
silver
present
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PCT/US2011/050929
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English (en)
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Joseph M. Mclellan
Graciela B. Blanchet
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Nano Terra Inc.
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/08—Materials not undergoing a change of physical state when used
    • C09K5/10—Liquid materials

Definitions

  • the present invention is directed to heat transfer fluids comprising nanomaterials, methods for making the heat transfer fluids and nanomaterials, and products prepared by the methods.
  • Fluids are often employed as the heat transfer media in cooling systems.
  • the heat transfer coefficient can be improved by increasing the velocity of recirculation or by increasing the thermal conductivity of the heat transfer medium.
  • the extent to which the thermal conductivity of conventional fluids can be improved is minimal, leaving increased velocity as the only practical means of improving the efficiency. This option typically comes at the cost of greater power and energy consumption.
  • Solids on the other hand, generally have thermal conductivities that are orders of magnitude greater than fluids.
  • the thermal conductivity of silver at room temperature is about 3000 times greater than that of engine oil, about 1700 times greater than that of ethylene glycol, and about 700 times greater than that of water.
  • Heat transfer fluids are of particular importance in transportation and cooling systems.
  • Transportation-born emissions are the second largest source of man-made carbon and were responsible for more than 23% of total emissions in developed countries in 2001.
  • Dedicated engine cooling systems are crucial components of all modern motor vehicles, preventing engine overheating and subsequent failure. Coolant in the engine absorbs heat and is pumped through a radiator, for example, where the coolant is air- cooled and then cycled back to the engine. Both the quantity and pumping speed of the coolant are determined by the thermal transfer coefficient of the fluid. Coolants with smaller coefficients require larger systems.
  • a thermal transfer coefficient of a fluid permits: 1) a lower quantity of coolant to be utilized; 2) reduction in radiator size (and weight); and 3) a lower power pump to be used for circulating the fluid.
  • Approximately 2.5% to 5% of a vehicle's energy is used to power a cooling system.
  • more efficient heat transfer fluids and smaller cooling systems can provide significant energy savings.
  • smaller radiators reduce weight and increase vehicle aerodynamics because radiators are a key source of drag, especially in large trucks.
  • Industrial cooling systems are typically closed loops in which water circulates to cool processing equipment, and chillers then remove heat from the cooling water.
  • chillers In these systems, the majority of energy is expended in the chilling and pumping processes, which account for about 1% to 2% of U.S. carbon emissions from manufacturing industries.
  • Maxwell predicted that the effective thermal conductivity of a suspension of spherical particles would increase as the volume fraction of solids was increased. See J.C. Maxwell, A Treatise on Electricity and Magnetism 1, 435, 2d. ed., Clarendon Press (1881). Early studies focused on particles with micron-to-millimeter dimensions, but these materials worked poorly due to the large size of the particles. Even with constant agitation, the fluids routinely clogged small passages and, additionally, the suspensions were often abrasive.
  • nanophase materials materials having a dimension of about 100 nm or less
  • advanced heat transfer fluids and termed these new materials nanofluids.
  • nanophase materials materials having a dimension of about 100 nm or less
  • nanofluids materials having a dimension of about 100 nm or less
  • nanoparticles can form stable suspensions that will typically do not clog even microscale passages.
  • nanoparticles have a much larger surface area-to-volume ratio than their microscale counterparts. This ratio is critical because thermal conductivity in a suspension is limited by the heat transfer between the base fluid and the particles, which occurs at the surface of the particles.
  • a mass of a material comprised of spheres with a diameter of 25 nm has 100- fold more surface area than the same mass of material composed of spheres with a diameter of 2.5 ⁇ .
  • nanofluid researchers have investigated the effects of particle size on fluid conductivity, the effects of particle geometry on conductivity are relatively unexplored. This is likely due to the difficulty of fabricating non-spherical particles.
  • precise control over particle geometry is critical for maximizing surface area.
  • the surface area of a 25 nm cubic nanoparticle is nearly twice that of a spherical nanoparticle with a 25 nm diameter.
  • nanofluid design requires flexible fabrication processes that are capable of producing nanoparticles with well-controlled sizes and geometries.
  • Nanofluids containing metal oxide nanoparticles are attractive due to the ease with which these particles can be fabricated.
  • a large volume fraction of particles must be used due to the limited intrinsic thermal conductivity of the oxide particles themselves.
  • a large volume fraction of particles also causes a dramatic increase in the viscosity and abrasiveness of a suspension, even when nanoparticles are used, which greatly diminishes the utility of a nanofluid.
  • Multi-walled carbon nanotubes dispersed in engine oil have also demonstrated impressive enhancements in the effective thermal conductivity (e.g., an enhancement of about 160% with a 1% volume fraction of nanotubes).
  • an enhancement of about 160% with a 1% volume fraction of nanotubes limits the practicality of these nanofluids.
  • the fluids of the present invention have a thermal conductivity that is several times, or an order of magnitude, or more, greater than the thermal conductivity of currently used cooling fluids.
  • the present invention is directed to a fluid composition comprising: a liquid carrier and a plurality of particles having an anisotropic shape.
  • the fluid compositions of the present invention have a high thermal conductivity, and can be used as a direct replacement for many currently used heat-transfer fluids.
  • the fibers have a cross-sectional dimension of 50 nm to 10 ⁇ , and at least one second dimension of 200 nm to 10 mm. In some embodiments, the particles have at least one dimension of 10 nm to 100 nm, and at least one second dimension of 10 nm to 250 nm.
  • the particles have an aspect ratio of 1.5 : 1 or higher.
  • At least a portion of the plurality of particles have a cage or porous structure.
  • the particles comprise a metal.
  • the plurality of particles is a mixture of particles comprising a metal selected from: copper, silver, gold, palladium, and combinations thereof
  • At least a portion of the plurality of particles comprise copper and have an anisotropic three dimensional shape selected from: a plate, a rod, a truncated prism, and combinations thereof.
  • At least a portion of the plurality of particles comprise silver and have an anisotropic three dimensional shape selected from: a cube, a bar, a plate, a wire, a rod, a right bipyramid, and combinations thereof.
  • At least a portion of the plurality of particles are silver nanocubes having a dimension of 100 nm or less per side.
  • At least a portion of the plurality of particles are silver tetragnoal pyramids having a dimension of 120 nm or less per side.
  • At least a portion of the plurality of particles are hollow silver-gold alloy nanocages having at least one dimension of 100 nm or less.
  • At least a portion of the plurality of particles are silver nanobars having an aspect ratio of at least 1 :2 and lateral dimensions of 50 nm or less and
  • At least a portion of the plurality of particles are silver nanorice having an aspect ratio of at least 1 :2 and lateral dimensions of 80 nm or less and 300 nm or less.
  • At least a portion of the plurality of particles are palladium nanoplates having a diameter of 15 nm to 80 nm.
  • At least a portion of the plurality of particles are silver nanoplates having a diameter of 20 nm to 200 nm.
  • At least a portion of the plurality of particles are silver right bi-pyramids having a dimension of 50 nm to 150 nm.
  • a fluid composition further comprises a solvent.
  • a fluid composition comprises a solvent selected from: water, an alcohol, a glycol, a glycol ester, a glycol ether, a ketone, an amide, an ester, an ether, a chlorinated solvent, an aromatic solvent, a petroleum grease, a petroleum oil, a silicone grease, a silicone oil, an ionic liquid, and combinations thereof.
  • a fluid composition further comprises a polymer.
  • At least a portion of the particles comprise a functional group. In some embodiments, at least a portion of the particles include a surface having a self-assembled monolayer thereon.
  • the fluid composition has a thermal conductivity at least
  • the present invention is also directed to a fluid composition
  • a fluid composition comprising: a liquid carrier comprising water and ethylene glycol, wherein the ethylene glycol is present in a concentration of 50% to 90% by volume of the liquid carrier; a polyvinylpyrrolidone polymer in a concentration of 1% by weight or less; and a plurality of particles comprising a metal selected from: gold, silver, and combinations thereof, wherein the particles are present in a concentration of 0.01% to 1% by weight, and wherein the particles have an anisotropic shape that includes at least one dimension of 10 nm to 100 ran, and at least one second dimension of 10 nm to 250 nm.
  • a fluid composition has a thermal conductivity of 2 W/m-K or greater, or 5 W/m-K or greater.
  • FIGs. 1A-1B, 1C, ID, IE, IF and 1G provide images of metal nanoparticles suitable for use with the present invention.
  • bottom made herein are for purposes of description and illustration only, and should be interpreted as non-limiting upon the fluids, materials, fibers, particles, methods, and products of the present invention, which can be spatially arranged in any orientation or manner.
  • the present invention is directed to nanomaterials (e.g., nanoparticles, nanofibers, and combinations thereof), nanofluids comprising the nanomaterials, methods to prepare the nanomaterials and fluids, and products prepared therefrom.
  • nanomaterials e.g., nanoparticles, nanofibers, and combinations thereof
  • nanofluids comprising the nanomaterials
  • methods to prepare the nanomaterials and fluids and products prepared therefrom.
  • a “nanomaterial” refers to a material having a discrete shape that includes at least one average lateral dimension (e.g., cross sectional dimension, width, height, diameter, and the like) less than 1 micron ( ⁇ ). In some embodiments, a nanomaterial has at least one cross-sectional dimension of 500 nm of less, 100 nm or less, or 50 nm or less.
  • nanoparticle refers to a material having a discrete shape and an aspect ratio between two dimensions (e.g., lengthiwidth, lengththeight, length:diameter, and the like) of 1.5 to 10, 2 to 10, 3 to 10, 5 to 10, 8 to 10, or about 10.
  • nanoparticles for use with the present invention are anisotropic, which refers to an aspect ratio of 1.5 or greater.
  • a nanoparticle of the present invention is a plate (i.e., has a flat or planar shape) in which at least one surface of the nanoparticle has a trigonal, square, rectangular, pentagonal, hexagonal, or octagonal shape.
  • a nanoparticle of the present invention has a polyhedral shape that includes at least one side or facet having a trigonal, square, rectangular, pentagonal, hexagonal, or octagonal shape, or a combination thereof.
  • a nanoparticle of the present invention has a ellipsoidal shape. In some embodiments, a nanoparticle of the present invention has a rod, platelet, wire, or ribbon shape. In some embodiments, a nanoparticle of the present invention has a right bi-pyramidal shape.
  • a nanofluid of the present invention includes a plurality of nanoparticles having a single predominant shape such as, for example, a rod shape.
  • a nanofluid of the present invention includes a mixture of nanoparticles having different shapes.
  • the plurality of nanoparticles can have the same or different compositions (e.g., a plurality of nanoparticles having the same shape, but different composition; a plurality of nanoparticles having a consistent composition, but different shapes; or a plurality of nanoparticles having diverse shapes and compositions).
  • a nanoparticle of the present invention has a cage structure.
  • the nanoparticles have at least one dimension (e.g., length, width, height, diameter, thickness, and the like) that has an average size of 10 nm to 100 nm, 10 nm to 80 nm, 10 nm to 75 nm, 10 nm to 70 nm, 10 nm to 65 nm, 10 nm to 60 nm, 10 nm to 50 nm, 10 nm to 45 nm, 10 nm to 40 nm, 10 nm to 35 nm, 10 nm to 30 nm, 10 nm to 25 nm, 10 nm to 20 nm, 20 nm to 100 nm, 20 nm to 80 nm, 20 nm to 75 nm, 20 nm to 70 nm, 20 nm to 65 nm, 20 nm to 60 nm, 20 nm to 50 nm, 20 nm to 45 nm,
  • Nanoparticles suitable for use with the present invention and methods of making the nanoparticles are also described in, for example, U.S. Pub. Nos. 2005/0056118, 2007/0289409, and 2008/0003130, the entire contents of which are incorporated herein by reference.
  • a nanoparticle for use with a nanofluid of the present invention comprises silver and has a cube, bar, rice, plate, wire, or right bipyramid shape.
  • a nanoparticle for use with a nanofluid of the present invention comprises copper Cu and has a plates or truncated prism shape having a ferret diameter of 10 nm to 100 nm and a thickness of 1 nm to 25 nm.
  • a “nanofiber” refers to a material having a discrete wire, thread, hair and/or tube-like shape that is generally longer than a particulate.
  • a nanofiber has an aspect ratio of a length to a cross-sectional dimension (e.g., length:width, length:height, length: diameter, and the like) of 10:1 or greater, 15:1 or greater, 20:1 or greater, 25:1 or greater, 30:1 or greater, or 50:1 or greater.
  • a nanofiber of the present invention has a cross-sectional shape selected from: a circle, an ellipse, a polyhedron (e.g., a trigonal, square, rectangular, pentagonal, hexagonal, or octagonal cross-section shape), a star, or a combination thereof.
  • a cross-sectional shape selected from: a circle, an ellipse, a polyhedron (e.g., a trigonal, square, rectangular, pentagonal, hexagonal, or octagonal cross-section shape), a star, or a combination thereof.
  • a nanofiber for use with the present invention has a cross- sectional dimension of 20 nm to 1 ⁇ , 50 nm to 900 nm, 100 nm to 800 nm, 150 nm to 700 nm, 200 nm to 600 nm, 250 nm to 500 nm, or 300 nm to 500 nm.
  • a nanofiber for use with the present invention has a length of 500 nm to 50 ⁇ , 1 ⁇ to 25 ⁇ , 1 ⁇ to 10 ⁇ , or 1 ⁇ to 5 ⁇ .
  • Nanofibers suitable for use with the present invention and methods of making the nanofibers are also described in, for example, U.S. Appl. Nos. 61/104,438, filed October 10, 2008, and 61/227,336, filed July 21, 2009, the entire contents of which are incorporated herein by reference.
  • a nanomaterial for use with the present invention comprises a material selected from: a metal, a polymer, a conductive polymer, a ceramic, a composite thereof, and combinations thereof. Other presently known and later developed materials can also be employed.
  • Nanofluids comprising metallic nanomaterials are particularly preferred because metal nanoparticles show extremely high enhancements in effective thermal conductivity, even at low nanomaterial volume fractions.
  • a nanomaterial for use with the present invention comprises a metal selected from: a transition metal, a group IIIB metal, a group IVB metal, and combinations thereof.
  • a nanomaterial for use with the present invention comprises a metal selected from: silver, copper, gold, nickel, rhodium, palladium, platinum, iridium, cobalt, chromium, aluminum, titanium, tin, and the like, an oxide thereof, and an alloy thereo
  • a nanomaterial for use with the present invention comprises a material selected from: a silver oxide (e.g., AgO), a titanium oxide (e.g., Ti0 2 ), a copper oxide (e.g., Cu 2 0), an aluminum oxide (e.g., A1 2 0 3 ), a germanium oxide (e.g., GeO), a zirconium oxide (e.g., Zr0 2 ), a yttrium oxide (e.g., Y 2 0 3 ), a zinc oxide (e.g., ZnO), a vanadium oxide (e.g., V 2 0 5 ), an indium oxide (e.g., InO), a tin oxide (e.g., SnO), an indium tin oxide, a suboxide thereof, a doped and/or alloyed form thereof, and combinations thereof.
  • a silver oxide e.g., AgO
  • a titanium oxide e.g., Ti0
  • Metallic and metal oxide nanofibers for use the present invention can be prepared by electrospinning a metal salt-polymer nanofiber followed by reduction or oxidation of the metal salt to form a metal or metal oxide.
  • Metallic and metal oxide nanofibers for use with the present invention include, but are not limited to, the metals and metal oxides listed above.
  • a nanomaterial is conductive or semiconductive.
  • conductive and semiconductive materials include species, compounds, polymers, and the like capable of transporting or carrying electrical charge.
  • the charge transport properties of a semiconductive material can be modified based upon an external stimulus such as, but not limited to, an electrical field, a magnetic field, a temperature change, a pressure change, exposure to radiation, and combinations thereof.
  • Electrically conductive and semiconductive materials include, but are not limited to, metals, alloys, crystals, amorphous materials, polymers, and combinations thereof
  • a nanofluid of the present invention is transparent, translucent, or opaque to visible, UV, and/or infrared light).
  • a nanofluid of the present invention is blue, green, red or black, and the nanofluid contains nanomaterials having an absorption in the visible, ultraviolet and/or infrared regions of the electromagnetic spectrum.
  • a nanomaterial absorbs electromagnetic radiation having at least one wavelength of 180 nm to 30 ⁇ .
  • a nanoparticle is substantially transparent to a light in a first region of the electromagnetic spectrum and has an absorption at a second wavelength range from 180 nm to 30 ⁇ .
  • nanomaterials present in a heat transfer fluid have approximately the same composition.
  • nanomaterials present in a heat transfer fluid of the present invention have compositions that differ from one another, or that differ substantially from one another.
  • a nanoparticle and/or nanofiber for use with the present invention is porous.
  • porous and “porosity” are interchangeable and refer to a structure comprising void space.
  • Nanoparticles and nanofibers for use with the present invention can have a porosity of 1% to 65% by volume, 5% to 60% by volume, 10% to 50% by volume, 15% to 40% by volume, or 20% to 30% by volume.
  • Nanomaterials for use with the present invention can be rigid or flexible.
  • a nanomaterial can undergo plastic deformation such that conformal contact can be made between a flexible nanomaterial and a curved or non-planar substrate.
  • a nanomaterial of the present invention has a Young's
  • the Young's Modulus of a nanomaterial of the present invention is substantially the same as the Young's Modulus a bulk material having the same composition as the nanomaterial.
  • a nanofluid of the present invention has a thermal conductivity of 2 W/m-K or greater, 5 W/m-K or greater, 10 W/m-K or greater, 15 W/m-K or greater, 20 W/m-K or greater, 25 W/m-K or greater, 30 W/m-K or greater, 50 W/m-K or greater, 75 W/m-K or greater, or 100 W/m-K or greater.
  • a nanofluid of the present invention has a thermal conductivity 2 W/m-K to 100 W/m-K, 2 W/m-K to 50 W/m-K, 2 W/m-K to 25 W/m-K, 2 W/m-K to 10 W/m-K, 5 W/m-K to 100 W/m-K, 5 W/m-K to 50 W/m-K, 5 W/m-K to 25 W/m-K, 10 W/m-K to 100 W/m-K, 10 W/m-K to 50 W/m-K, 10 W/m-K to 25 W/m-K, 25 W/m-K to 100 W/m-K, or 25 W/m-K to 50 W/m-K.
  • a nanofluid of the present invention exhibits an increase in thermal conductivity of 1.5-fold, two-fold, 2.5-fold, three-fold, four- fold, five-fold, sixfold, eight-fold, nine-fold, or ten-fold or more compared to a fluid lacking the nanoparticles but otherwise having the same composition.
  • a nanofluid can exhibit significant increase in thermal conductivity at low nanomaterial loadings.
  • a nanofluid of the present invention comprises a nanomaterial (i.e., nanoparticles and/or nanofibers) in a concentration of 0.5% to 80%, 0.5% to 75%, 0.5% to 70%, 0.5% to 60%, 0.5% to 50%, 0.5% to 40%, 0.5% to 30%, 0.5% to 25%, 0.5% to 20%, 0.5% to 15%, 0.5% to 10%, 0.5% to 7.5%, 0.5% to 5%, 0.5% to 4%, 0.5% to 3%, 0.5% to 2%, 0.5% to 1%, 1% to 50%, 1% to 25%, 1% to 10%, 5% to 80%, 5% to 70%, 5% to 60%, 5% to 50%, 5% to 40%, 5% to 30%, 5% to 25%, 5% to 20%, 5% to 15%, 5% to 10%, 10% to 80%, 10% to 50%, 10% to 25%, 15% to 80%, 15% to 50%, 15% to 40%, 15% to 30%, 20% to 80%, 20% to 70%, 20% to 60%, 20% to 50%, 25% to 7
  • the nanomaterials within a heat transfer fluid of the present invention are not functionalized and/or derivatized.
  • nanomaterials of the present invention are functionalized and/or derivatized.
  • “functionalized” and “derivatized” refer to the attachment of a chemical group, ligand, species, moiety, and the like to a surface of a nanomaterial.
  • nanomaterials are derivatized with a molecular species as described herein.
  • At least a portion of a nanomaterial surface is derivatized with a monolayer-forming species, for example a self-assembled monolayer forming species.
  • a monolayer-forming species for example a self-assembled monolayer forming species.
  • at least a portion of the particles include a surface having a self-assembled monolayer thereon.
  • a self-assembled monolayer can be formed on at least a portion of a metal nanomaterial surface using, for example, a thiol group.
  • functionalization and derivatization can be achieved via a covalent bonding interaction, an ionic bonding interaction, a hydrogen bonding interaction, a non-bonding interaction, an intercalation interaction, physical entanglement, a chiral interaction, a magnetic interaction, and combinations thereof.
  • derivatization and/or functionalization of the anisotropic nanomaterials can be useful for modifying a chemical and/or thermal interface between the nanomaterials and a fluid.
  • derivatization and/or functionalization of the anisotropic nanomaterials can increase the dispersibility of the nanomaterials in a fluid, increase the solubility of nanomaterials in a fluid, increase the hydrophobicity of nanomaterials, increase the hydrophilicity of nanomaterials, increase the thermal conductivity of the nanomaterials in a fluid, and combinations thereof.
  • a self-assembled monolayer on at least a portion of a surface of a nanomaterial can also improve the chemical stability of the nanomaterial by, e.g., preventing oxidation, as well maintaining the stability of the nanofluid against agglomeration and/or sedimentation.
  • Functional groups suitable for imparting hydrophilicity to a nanomaterial of the present invention include, but are not limited to, hydroxyl, alkoxyl, thiol, thioalkyl, silyl, alkylsilyl, alkylsilenyl, siloxyl, primary amino, secondary amino, tertiary amino, carbonyl, alkylcarbonyl, aminocarbonyl, carbonylamino, carboxy, alkylenedioxy, and combinations thereof.
  • increasing the length of an alkyl, alkenyl, or alkynyl chain will increase the hydrophobicity of a nanomaterial's surface.
  • alkyl by itself or as part of another group, refers to straight and branched chain hydrocarbons of up to 60 carbon atoms, such as, but not limited to, octyl, decyl, dodecyl, hexadecyl, and octadecyl.
  • alkenyl by itself or as part of another group, refers to a straight and branched chain hydrocarbons of up to 60 carbon atoms, wherein there is at least one double bond between two of the carbon atoms in the chain, and wherein the double bond can be in either of the cis or trans configurations, including, but not limited to, 2-octenyl, 1-dodecenyl, 1-8-hexadecenyl, 8-hexadecenyl, and 1-octadecenyl.
  • alkynyl by itself or as part of another group, refers to straight and branched chain hydrocarbons of up to 60 carbon atoms, wherein there is at least one triple bond between two of the carbon atoms in the chain, including, but not limited to, 1-octynyl and 2-dodecynyl.
  • aryl by itself or as part of another group, refers to cyclic, fused cyclic, and multi-cyclic aromatic hydrocarbons containing up to 60 carbons in the ring portion. Typical examples include phenyl, naphthyl, anthracenyl, fluorenyl, tetracenyl, pentacenyl, hexacenyl, perylenyl, terylenyl, quaterylenyl, coronenyl, fullerenyl and buckminsterfullereny 1.
  • aralkyl or “arylalkyl,” by itself or as part of another group, refers to alkyl groups as defined above having at least one aryl substituent, such as benzyl, phenylethyl, and 2-naphthylmethyl.
  • alkylaryl refers to an aryl group, as defined above, having an alkyl substituent, as defined above.
  • heteroaryl by itself or as part of another group, refers to cyclic, fused cyclic and multicyclic aromatic groups containing up to 30 atoms in the ring portions, wherein the atoms in the ring(s), in addition to carbon, include at least one heteroatom.
  • heteroatom is used herein to mean an oxygen atom ("O"), a sulfur atom ("S”) or a nitrogen atom (“N”).
  • heteroaryl also includes TV-oxides of heteroaryl species that containing a nitrogen atom in the ring. Typical examples include pyrrolyl, pyridyl, pyridyl JV-oxide, thiophenyl, and furanyl.
  • Any one of the above groups can be farther substituted with at least one of the following substituents: hydroxyl, alkoxyl, thiol, alkylthio, silyl, alkylsilyl, alkylsilenyl, siloxyl, primary amino, secondary amino, tertiary amino, carbonyl, alkylcarbonyl, aminocarbonyl, carbonylamino, carboxy, halo, perhalo, alkylenedioxy, and combinations thereof.
  • hydroxyl by itself or as part of another group, refers to an
  • alkoxyl by itself or as part of another group, refers to one or more alkoxyl (-OR) moieties, wherein R is selected from the alkyl, alkenyl, alkynyl, aryl, aralkyl, and heteroaryl groups described above.
  • thiol by itself or as part of another group, refers to an (-SH) moiety.
  • alkylthio refers to an (-SR) moieties, wherein R is selected from the alkyl, alkenyl, alkynyl, aryl, aralkyl, and heteroaryl groups described above.
  • sil by itself or as part of another group, refers to an (-Si3 ⁇ 4) moiety.
  • alkylsilyl by itself or as part of another group, refers to an
  • alkylsilenyl by itself or as part of another group, refers to a
  • R is selected from the alkyl, alkenyl, alkynyl, aryl, aralkyl, and heteroaryl groups described above.
  • silica by itself or as part of another group, refers to a
  • secondary amino by itself or as part of another group, refers to an (-NRH) moiety, wherein R is selected from the alkyl, alkenyl, alkynyl, aryl, aralkyl, and heteroaryl groups described above.
  • tertiary amino by itself or as part of another group, refers to an
  • R and R 1 are independently selected from the alkyl, alkenyl, alkynyl, aryl, aralkyl, and heteroaryl groups described above.
  • alkylcarbonyl by itself or as part of another group, refers to a
  • R is independently selected from hydrogen and the alkyl, alkenyl, alkynyl, aryl, aralkyl, and heteroaryl groups described above.
  • aminocarbonyl by itself or as part of another group, refers to a
  • R and R 1 are independently selected from hydrogen and the alkyl, alkenyl, alkynyl, aryl, aralkyl, and heteroaryl groups described above.
  • R is independently selected from hydrogen and the alkyl, alkenyl, alkynyl, aryl, aralkyl, and heteroaryl groups described above.
  • alkylenedioxy by itself or as part of another group, refers to a ring and is especially C 1-4 alkylenedioxy. Alkylenedioxy groups can optionally be substituted with halogen (especially fluorine). Typical examples include methylenedioxy (-OCH 2 0-) or difmoromethylenedioxy (-OCF 2 0-).
  • halo by itself or as part of another group, refers to any of the above alkyl, alkenyl, alkynyl, aryl, aralkyl, and heteroaryl groups wherein one or more hydrogens thereof are substituted by one or more fluorine, chlorine, bromine, or iodine atoms.
  • perhalo by itself or as part of another group, refers to any of the above alkyl, alkenyl, alkynyl, aryl, aralkyl, and heteroaryl groups wherein all of the hydrogens thereof are substituted by fluorine, chlorine, bromine, or iodine atoms.
  • a nanomaterial of the present invention has a fluorinated surface.
  • a fluorinated moiety refers to a molecule, particulate, or molecular species that contains a bond to fluorine and can be used to derivatize a nanomaterial of the present invention.
  • a fluorinated moiety comprises a C-F bond and/or an Si-F bond.
  • an outer surface of a nanomaterial is fluorinated (e.g., by exposure to F 2 , SiF 4 , SF 6 , a fluorinated alkyl and/or alkoxy silane, and the like, as well as other fluorination processes that would be apparent to a person of ordinary skill in the art of surface fluorination) to provide a fluorinated surface.
  • a nanomaterial is derivatized with a self-assembled monolayer forming species comprising any of the above alkyl, alkenyl, alkynyl, aryl, aralkyl, and heteroaryl groups containing a functional group suitable for forming a bond with a metal.
  • a self-assembled monolayer forming species includes one or more hydroxyl, thiol, silyl, primary amino, secondary amino, and/or carboxyl groups.
  • the nanomaterials are hydrophobic.
  • a nanomaterial is derivatized with a hydrophobic functional group.
  • hydrophobic refers to coatings that have a tendency to repel water, are resistant to water and/or cannot be wetted by water.
  • a hydrophobic nanomaterial comprises a surface that is at least 50%, at least 60%, at least 70%, or at least 80% covered by a hydrophobic molecular species.
  • a hydrophobic molecular species comprises an optionally substituted Q-Ceo alkyl, an optionally substituted C 2 -C 60 alkenyl, an optionally substituted C 2 -C 60 alkynyl, an optionally substituted C 6 -C 60 aryl, an optionally substituted C 6 -C 60 aralkyl, an optionally substituted C 6 -C 60 heteroaryl, and combinations thereof, wherein these groups can be linear or branched.
  • Optional substituents for hydrophobic molecular species include, but are not limited to, a halo and perhalo (i.e., wherein halo is any one of: fluorine, chlorine, bromine, iodine, and combinations thereof), alkylsilyl, siloxyl, tertiary amino, and combinations thereof.
  • an optionally substituted hydrophobic molecular species is chosen from a Q-C60 fluoroalkyl, a Q-C60 perfluoroalkyl, and combinations thereof.
  • a nanofluid of the present invention can further comprise a component selected from: an isotropic nanoparticle, a nanofiber, a solvent, a polymer, a surfactant, a dispersant, a stabilizer, an antioxidant, a chelator, and the like, and combinations thereof.
  • a nanofluid of the present invention can further comprise a component selected from: an isotropic nanoparticle, an anisotropic nanoparticle, a nanofiber, a solvent, a polymer, a surfactant, a dispersant, a stabilizer, an antioxidant, a chelator, and the like, and combinations thereof.
  • a nanofluid of the present invention comprises a solvent.
  • Solvents suitable for use with the present invention include both aqueous and nonaqueous solvents and solvent mixtures.
  • a composition of the present invention includes an aliphatic non-aqueous solvent, an aromatic non-aqueous solvent, or a combinations thereof.
  • Solvents suitable for use with the present invention also include, but are not limited to, water, an alcohol (e.g., methanol, ethanol, propanol, butanol, pentanol, hexanol, and the like), a glycol (e.g., ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, and the like, and ethers and esters thereof such as, but not limited to, ethylene glycol dimethylether, ethylene glycol diethylether), a ketone (e.g., acetone, methylethylketone, butanone, and the like), an amide (e.g., dimethylformamide, dimethylacetamide, and the like), an ester (e.g., ethylacetate, and the like), an ether (e.g., dimethylether, dipropylether, and the like), N-methylpyrrolidone (NMP), a chlorinated solvent (e
  • a solvent is a glycol or an ether or ester thereof selected from: ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol methyl ether acetate, ethylene glycol monethyl ether acetate, ethylene glycol monobutyl ether acetate, and the like, and combinations thereof,
  • the nanofluid comprises an aqueous solution that includes a glycol in a concentration of 50% to 90%, 50% to 75%, 60% to 90%, 75% to 90%, about 50%), about 60%, about 75%, or about 90% by volume.
  • the glycol is ethylene glycol.
  • a nanofluid of the present invention comprises a polymer such as, but not limited to, a polyvinylpyrrolidone, a cellulose (e.g., a methylcellulose, ethylcellulose, a hydroxyethylcellulose, a hydroxypropylmethylcellulose, a carboxymethylcellulose, and the like), a polyethylene glycol, a polypropylene glycol, a polyacrylic acid, a polyvinylacetate, a polyvinylalcohol, and the like, and combinations thereof.
  • a polymer such as, but not limited to, a polyvinylpyrrolidone, a cellulose (e.g., a methylcellulose, ethylcellulose, a hydroxyethylcellulose, a hydroxypropylmethylcellulose, a carboxymethylcellulose, and the like), a polyethylene glycol, a polypropylene glycol, a polyacrylic acid, a polyvinylacetate, a polyviny
  • a polymer is present in a concentration of 5% or less, 2.5% or less, 1% or less, 0.5%) or less, or 0.1% or less, by weight of a composition.
  • a polymer can function as a stabilizer in a nanofluid of the present invention, for example, to provide enhanced flowability and/or to prevent agglomeration, sedimentation, and/or oxidation.
  • a nanofluid of the present invention comprises an anisotropic nanoparticle, a solvent and a polymer.
  • the present invention is directed to a fluid composition comprising: a liquid carrier comprising water and ethylene glycol, wherein the ethylene glycol is present in a concentration of 50% to 90% by volume of the liquid carrier; a polyvinylpyrrolidone polymer in a concentration of 1% by weight or less; and a plurality of particles comprising a metal selected from: gold, silver, and combinations thereof, wherein the particles are present in a concentration of 0.01% to 1% by weight, and wherein the particles have an anisotropic shape that includes at least one dimension of 10 nm to 100 nm, and at least one second dimension of 10 nm to 250 nm.
  • a nanofluid of the present invention comprises a nanofiber, a solvent and a polymer.
  • the present invention is directed to a fluid composition comprising: an aqueous liquid carrier, a polyvinylpyrrolidone polymer in a concentration of 1% by weight or less, and a plurality of nanofibers comprising a metal selected from: nickel, copper, zinc, iron, an oxide thereof, and combinations thereof, wherein the nanofibers have an average cross-sectional dimension of 100 nm to 500 nm and an average length of 1 ⁇ to 25 ⁇ .
  • the nanofluids and nanomaterials of the present invention exhibit wear resistance, dimensional stability, and chemical stability that makes them suitable for use in a wide range of environments. Additionally, the nanofluids of the present invention are robust and stable for an extended period of time. In some embodiments, a nanofluid of the present invention is stable for at least 200 hours, at least 300 hours, at least 400 hours, at least 500 hours, at least 600 hours, at least 700 hours, at least 800 hours, at least 900 hours, at least 1,000 hours, at least 1,200 hours, at least 1,500 hours, or at least 2,000 hours without agitation.
  • nanomaterials and nanofluids of the present invention are compatible with a variety of materials without inducing corrosion of the bulk and/or surface of a material.
  • a nanomaterials suspension and/or nanofluid of the present invention is compatible with 6061 aluminum, stainless steel, polycarbonate, silica, quartz, and the like.
  • the nanofluids of the present invention are suitable for application in cooling systems, solar energy conversion systems, photovoltaic systems, electrical systems, consumer electronics, industrial electronics, automobiles, military applications, space applications, and any other applications in which heat transfer fluids are required or desirable.
  • Properties of the fluid compositions of the present invention that can be optimized and/or controlled include, but are not limited to, composition, stoichiometry, viscosity, thermal conductivity, density, light absorption, electrical conductivity, chemical stability, and the like, and combinations thereof. Properties of the nanomaterials and fluid compositions of the present invention can be measured using analytical tools and methods known to persons of ordinary skill in the art.
  • a nanofluid of the present invention is robust and can be used in a wide variety of industrial applications without undergoing physical and/or chemical degradation or resulting in damage to equipment.
  • a nanofluid of the present invention has a lifetime of 5,000 hours or more, 10,000 hours or more, 15,000 hours or more, or 20,000 hours or more.
  • a nanofluid of the present invention can be used with a heat transfer apparatus comprising at least one opening having a diameter of 100 ⁇ or less, 50 ⁇ or less, 25 ⁇ or less, 10 ⁇ or less, or 5 ⁇ or less without sedimentation and/or clogging.
  • the present invention is also directed to an apparatus suitable for testing thermal conductivity of nanofluids.
  • an apparatus of the present invention enables prediction of nanofluid performance based on a nanomaterial and/or bulk material property.
  • the present invention enables the heat transfer and thermal conductivity properties for a nanofluid composition to be predicted based on the shape, surface area, surface area to volume ratio, surface area to mass ratio, composition and/or concentration of a nanomaterial present in a fluid, as well as properties such as the fluid composition, fluid density, fluid viscosity, and the like.
  • FIG. 1A provides a scanning electron microscope ("SEM") image, 100, of a collection of silver nanocubes, 101, and tetragnoal pyramids, 102, suitable for use with the present invention.
  • the silver nanocubes, 101 have a dimension of about 100 nm per side
  • the tetragnoal pyramids, 102 have a dimension of about 120 nm per side.
  • FIG. IB provides a SEM image, 110, of a collection of hollow silver-gold alloy nanocages, 111, suitable for use with the present invention.
  • the silver-gold alloy nanocages, 111 have at least one dimension of about 100 nm.
  • FIG. 1C provides a SEM image, 120, of a collection of silver nanobars, 121 and
  • the silver nanobars, 121 and 122 have dimensions of about 40 nm and about 160 nm, about 50 nm and about 90 nm, respectively.
  • the silver nanocubes, 123 have at least one dimension of about 60 nm.
  • FIG. ID provides a SEM image, 130, of a collection of silver “nanorice” particles, 131, suitable for use with the present invention.
  • the silver "nanorice” particles, 131 have a width of about 60 nm and a length of about 60 nm to about 180 nm.
  • FIG. IE provides a transmission electron microscope ("TEM") image, 140, of palladium nanoplates, 141 and 142, suitable for use with the present invention.
  • TEM transmission electron microscope
  • Some of the palladium nanoplates, 141 have a trigonal shape and a dimension of about 15 nm to about 50 nm.
  • Other of the palladium nanoplates, 142 have a circular or multifaceted shape and a diameter of about 20 nm to about 50 nm.
  • FIG. IF provides a TEM image, 150, of a collection of silver nanoplates, 151, suitable for use with the present invention.
  • the silver nanoplates, 151 have a multifaceted shape with a diameter of about 10 nm to about 40 nm.
  • FIG. 1G provides a SEM image, 160, of a collection of silver right bi-pyramids,
  • the silver right bi-pyramids, 161 have a dimension of about 100 nm to about 120 nm.
  • Alumina particles having an average particle size of 50 nm (20% by weight) were slowly added to the solution of water and ethylene glycol described in Comparative Example 7. The alumina particles were added while constantly stirring the solution with a magnetic stirrer. The thermal conductivity of the resulting mixture was measured at 0.46 W/mK, an improvement of 15% over the solution lacking the alumina particles.
  • Alumina particles having an average particle size of 50 nm (80% by weight) were slowly added to the solution of water and ethylene glycol described in Comparative Example 7. The alumina particles were added while constantly stirring the solution with a magnetic stirrer. The thermal conductivity of the resulting mixture was measured at 0.56 W/mK, an improvement of 40% over the solution lacking the alumina particles.
  • anisotropic nanoparticles of any of Examples 1-6, or a combination thereof can be mixed with water to provide an aqueous nanofluid.
  • anisotropic nanoparticles of any of Examples 1-6, or a combination thereof can be mixed with ethylene glycol to provide a non-aqueous nanofluid.
  • anisotropic nanoparticles of any of Examples 1-6, or a combination thereof can be mixed with a mixture of water and ethylene glycol to provide an aqueous nanofluid.
  • anisotropic nanoparticles of any of Examples 1-6, or a combination thereof can be mixed with diethylene glycol to provide a non-aqueous nanofluid.
  • anisotropic nanoparticles of any of Examples 1-6, or a combination thereof can be mixed with propylene glycol to provide a non-aqueous nanofluid.
  • the anisotropic nanoparticles of any of Examples 1-6, or a combination thereof, can be mixed with a silicone oil (available from, e.g., Acros Organics N.V., Fair Lawn, NJ) and/or a silicone grease (available from, e.g., Dow Corning, Midland, MI) to provide a non-aqueous nanofluid.
  • a silicone oil available from, e.g., Acros Organics N.V., Fair Lawn, NJ
  • a silicone grease available from, e.g., Dow Corning, Midland, MI
  • a mixture of silver and gold anisotropic nanoplates can be added to a mixture of water and ethylene glycol (50%-90% ethylene glycol in water, v/v) containing a polyvinylpyrrolidone polymer (1% by weight) to provide an aqueous nanofluid.
  • the silver nanoplates and the gold nanoplates can be present in the nanofluid composition in a total concentration of about 0.01% to about 1% by weight.
  • Fibers comprising a zinc salt (zinc nitrate) and a polymer (polyvinylpyrrolidone), 1 : 1 by weight, "Zn(nitrate)-PVP fibers" were electrospun by the following procedure.
  • a first solution comprising zinc nitrate (1.6 M) was prepared by vortex mixing zinc nitrate in deionized water until a clear solution was provided.
  • a second solution comprising polyvinylpyrrolidone was prepared by vortex mixing polyvinylpyrrolidone (about 0.45 g, having an average molecular weight of 1.5 million Da) in ethanol (about 3.8 mL) until a clear solution was provided.
  • the first and second solutions were then vortex mixed with each other to provide a precursor solution.
  • Zn(nitrate)-PVP fibers were prepared by flowing the precursor solution at a flow rate of about 0.1 mL/hr to about 0.3 mL/hr through a 23 gauge needle (a 21 to 29 gauge needle can be used) to which was applied a DC voltage of about 10 kV to about 30 kV.
  • a collector (a metal plate, either grounded or negatively biased with a DC voltage of about -1 kV to about -10 kV) was placed about 100 mm to about 200 mm from the needle tip.
  • Composite Zn(nitrate)-PVP fibers were collected using the collector.
  • the Zn(nitrate)-PVP fibers prepared in Example 11 were converted to metallic zinc fibers by heating the nanowires and substrate to 550° C in a reducing atmosphere (4% H 2 in N 2 ), at a ramp rate of about 2° C per minute, holding at 550° C for about 13 hours, and then cooling the fibers to room temperature (about 21° C) over about 4 hours to provide metallic zinc fibers. Subsequent exposure of the zinc metal fibers to air resulted in the formation of a zinc oxide layer on the surface of the metal fibers, thereby providing zinc metal fibers having a zinc oxide surface layer thereon.
  • the zinc metal fibers of Example ⁇ 2 can be broken into smaller pieces having a length of about 1 ⁇ to about 1 mm, and mixed with propylene glycol (or another solvent listed herein) to provide a non-aqueous fluid composition comprising a metallic fiber.

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Abstract

Cette invention concerne des nanofluides comprenant des nanomatériaux, des procédés pour les préparer, et des produits préparés par les procédés selon l'invention.
PCT/US2011/050929 2010-09-09 2011-09-09 Fluides caloporteurs comprenant des nanomatériaux et leurs procédés de préparation et d'utilisation WO2012033975A1 (fr)

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JPWO2014203831A1 (ja) * 2013-06-17 2017-02-23 バイオエポック株式会社 ラジエター添加剤およびその使用方法
CN107350468A (zh) * 2017-06-22 2017-11-17 中国科学院合肥物质科学研究院 一种三维多孔金‑银合金纳米材料及其制备方法与应用

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