Nanowire Networks

Abstract

The present invention refers to a method for preparing a network of nanowires, to a network of nanowires obtainable by said method, to a nonwoven material comprising the network, to an electrode comprising the network, to a pharmaceutical composition 10 comprising a network of nanowires, to the use of the network of nanowires, and to the use of the nonwoven material.

Description

[Technical Field]

[0001] The present invention relates to the synthesis of nanowire networks, and more particularly to a process for preparing said nanowire networks. [Background technology]

[0002] Networks composed of nanowires offer advantages over materials made from larger building blocks. Generally, nanowires are mechanically flexible due to their nanoscale dimensions and have reduced amounts of defects compared to bulk materials. They also exhibit diverse optoelectronic properties as a result of their small size and one-dimensional morphology. Consequently, some of the properties of nanowire networks depend on the properties of the nanowires. Thus, there is a need for advanced control over the crystalline quality, morphology, and size distribution of nanowires.

[0003] Heurlin, M. et al. (Nature volume 492, pages 90-94, 2012) disclose an aerosol-assisted nanowire growth method (aerotaxy method) in which size-selected catalytic Au aerosol particles induce the nucleation and growth of GaAs nanowires at a growth rate of approximately 1 micrometer per second. The effectiveness of the aerotaxy method has only been demonstrated for the synthesis of GaAs (GaAsNW), P-doped, Zn-doped, and Sn-doped GaAsNW nanowires, and InP nanoparticles (Magnusson, MH et al. Frontiers of Physics, 9(3), 398-418, 2014). International Patent Publication No. WO2013176619(A1) describes a vapor-phase nanowire synthesis method in which individual silicon nanowires are grown and then, in a subsequent step, sprayed through a spray nozzle and then deposited on a substrate to form a nanowire network. According to International Patent Publication No. WO2013176619(A1), the spraying and deposition steps may be performed immediately after nanowire synthesis or after storing the nanowires in a reservoir. However, the two-step method of synthesizing nanowire networks leads to nanowire shortening and therefore material degradation. Furthermore, the nanowires that form the network are not permanently entangled or connected and must be deposited on a supporting substrate to produce a free-standing material.

[0004] In summary, there is a need to develop a one-step method for synthesizing nanowire networks with good mechanical properties that overcomes the limitations of the prior art. Summary of the Invention

[0005] The present inventors have discovered a one-step method for fabricating free-standing networks of nanowires with good mechanical properties, e.g., good flexibility in bending, where the nanowires have a high aspect ratio. The discovery of free-standing networks of nanowires that are also flexible is a breakthrough because it allows for the manipulation of the nanowire network after fabrication as an engineering material, rather than as a powder or filler, which typically suffers from degradation and / or nanowire shortening during dispersion during processing. In addition, the inventors have realized that the method of the present invention allows for the mass and rapid fabrication of nanowire networks. This approach is of great importance for the wide variety of applications of nanowire networks in various technological fields because it overcomes the current limitations of the prior art.

[0006] The method of the present invention is based on aerosol technology and has the potential to be scaled up to produce large quantities of product while providing a high level of control over the process.

[0007] Thus, in a first aspect, the present invention provides: i. providing a first gas stream to a reaction vessel, a first gas flow comprising at least one precursor compound comprising at least one element selected from Si, Ge, Al, B, Cu, Zn, Cd, Al, Ga, In, As, Sb, Nb, Ni, Ti, Se, Ta, Pt, Mo, W, C, N, O, Co, Mn, Li, and Te; ii. providing a second gas stream comprising metallic catalyst particles to the reaction vessel and mixing the first and second gas streams in the reaction vessel to form a gas stream mixture; at least one precursor compound is present in the gas stream mixture at a mole fraction (xi) of at least 0.005; the temperature in the reaction vessel is in the range of 200 to 800°C, or at least 801°C; The present invention relates to a method for preparing a network of nanowires, in which at least one precursor compound decomposes under temperature in a reaction vessel and grows on metallic catalyst particles by vapor-liquid-solid (VLS) and / or chemical vapor deposition (CVD) methods to form a network of nanowires.

[0008] In a second aspect, the present invention is directed to a network of nanowires obtainable by a method as defined above, wherein the aspect ratio (length / diameter) of the nanowires of the network of nanowires is at least 130.

[0009] In a third aspect, the present invention is directed to a nonwoven material comprising a network of nanowires of the present invention.

[0010] Another aspect of the present invention is directed to an electrode comprising a network of nanowires of the present invention in any of the detailed embodiments of the present invention or a nonwoven material of the present invention, and optionally an electrical connection or current collector, preferably a conductive wire or current collector, wherein the electrical connection or current collector and the network of nanowires are electrically connected.

[0011] In a further aspect, the present invention is directed to the use of the nanowire networks of the present invention in electronic devices, micromechanical systems, optoelectronic devices, wearable devices, insulators, sensors, electrodes, catalysis, structural components, batteries, flexible devices, radiation absorbing materials, and transparent devices.

[0012] In a further aspect, the present invention is directed to the use of the nonwoven materials of the present invention in electronic devices, micromechanical systems, optoelectronic devices, wearable devices, insulators, sensors, electrodes, catalysis, structural components, batteries, flexible devices, radiation absorbing materials, and transparent devices.

[0013] In a further aspect, the present invention is directed to a pharmaceutical composition comprising the network of nanowires of the present invention or the nonwoven material of the present invention. [Brief explanation of the drawings]

[0014] [Figure 1] Figure 1 shows a sketch of a continuous synthesis system including: (1) a silicon precursor inlet; (2) an aerosol inlet for catalyst nanoparticles; (3) a mixing region for the silicon precursor and catalyst streams; (4) a silicon nanowire nucleation region; (5) a region for silicon nanowire elongation / growth and entanglement; and (6) a region for spinning, drawing, and / or collecting nonwoven materials (e.g., fibers) containing silicon nanowires. [Figure 2] FIG. 2 shows a transmission electron micrograph showing silicon nanowires. [Figure 3] FIG. 3 shows a scanning electron microscope photograph showing the silicon nanowire network obtained in the present invention. [Figure 4] FIG. 4 shows the free-standing network of silicon nanowires obtained in the present invention. [Figure 5] FIG. 5 shows a bent and deformed piece of the silicon nanowire network obtained in the present invention. [Figure 6] FIG. 6 shows the mechanical testing results of the nanowire networks. DETAILED DESCRIPTION OF THE INVENTION

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0016] The present invention is directed to methods for preparing nanowire networks, nanowire networks obtainable by said methods, nonwoven materials comprising nanowire networks, uses of the nanowire networks and nonwoven materials of the invention, and pharmaceutical compositions comprising the nanowire networks of the invention or the nonwoven materials of the invention.

[0017] The nanowires of the nanowire networks of the present invention are high aspect ratio structures and may be made of solid material or may be hollow (have a tubular shape). In one embodiment, the nanowires are continuous structures (non-porous). In another embodiment, the nanowires form a network by joining together during their synthesis.

[0018] method In a first aspect, the present invention provides a method for producing a medicament for the treatment of a pulmonary arthritis, comprising: i. providing a first gas stream to a reaction vessel, a first gas flow comprising at least one precursor compound comprising at least one element selected from Si, Ge, Al, B, Cu, Zn, Cd, Al, Ga, In, As, Sb, Nb, Ni, Ti, Se, Ta, Pt, Mo, W, C, N, O, Co, Mn, Li, and Te; ii. providing a second gas stream comprising metallic catalyst particles to the reaction vessel and mixing the first and second gas streams in the reaction vessel to form a gas stream mixture; at least one precursor compound is present in the gas stream mixture at a mole fraction (xi) of at least 0.005; the temperature in the reaction vessel is in the range of 200 to 800°C, or at least 801°C; The present invention relates to a method for preparing a network of nanowires, in which at least one precursor compound decomposes under temperature in a reaction vessel and grows on metallic catalyst particles by vapor-liquid-solid (VLS) and / or chemical vapor deposition (CVD) methods to form a network of nanowires.

[0019] The method for preparing a network of nanowires may include the further step of converting the network of nanowires into a fiber, yarn, or fabric, which step is optionally carried out simultaneously with step (ii) of the method of the present invention.

[0020] In particular embodiments, the method for preparing a nanowire network includes the further step of recovering the nanowire network, particularly by spinning the nanowire network (as yarn or fabric) and winding it onto a bobbin.

[0021] In one embodiment, the process of the present invention is a continuous aggregation process.

[0022] Step (i) The method for preparing a nanowire network of the present invention comprises step (i) of providing a first gas stream to a reaction vessel, wherein the first gas stream comprises at least one precursor compound comprising at least one element selected from Si, Ge, Al, B, Cu, Zn, Cd, Al, Ga, In, As, Sb, Nb, Ni, Ti, Se, Ta, Pt, Cu, Mo, W, C, N, O, Co, Mn, Li, and Te.

[0023] In a detailed embodiment, the first gas flow further comprises H2. In a detailed embodiment, the first gas flow further comprises an inert gas, particularly N2.

[0024] precursor Step (i) of the method of the present invention provides a first gas stream to a reaction vessel, said first gas stream comprising at least one precursor compound. In particular embodiments, the at least one precursor compound is a compound that participates in a reaction (i.e., a chemical reaction) that produces the nanowire network of the present invention; for example, SiH4 is a precursor compound that may result in a Si nanowire network when used in the method of the present invention.

[0025] In particular embodiments, at least one precursor compound of the method of the present invention comprises at least one element selected from Si, Ge, Al, B, Cu, Zn, Cd, Al, Ga, In, As, Sb, Nb, Ni, Ti, Se, Ta, Pt, Cu, Mo, W, and Te, particularly Si, Ge, In, Ga, Se, and Te, more particularly Si and Ge, and even more particularly Si.

[0026] In particular embodiments, the at least one precursor compound is one precursor compound.

[0027] The at least one precursor compound may be in solid or liquid form (i.e., aerosolized in the first gas stream of the method of the present invention), or in gas form. In particular embodiments, the at least one precursor compound is in gas form.

[0028] In a detailed embodiment, at least one precursor compound of the method of the present invention is a metal hydride or an organometallic compound. Precursors of the present invention include (3-aminopropyl)triethoxysilane, N-sec-butyl(trimethylsilyl)amine, chloropentamethyldisilane, tetramethylsilane, silicon tetrabromide, silicon tetrachloride, tris(tert-butoxy)silanol, SiH4, tetramethylgermanium, triethylgermanium hydride, triphenylgermanium hydride, triphenylgermanium hydride, tetramethylgermanium, tributylgermanium hydride, triethylgermanium hydride, tris(tert-butoxy)silanol, tetramethylgermanium, triethylgermanium hydride, triphenylgermanium hydride, trimethylgermanium, tributylgermanium hydride, triethylgermanium hydride, tris(tert-butoxy)silanol, tetramethylgermanium, triethylgermanium hydride, tris(tert-butoxy)silanol ... Compounds such as phenylgermanium hydride, trimethylindium (TMin), trimethylindium (TEIN), trimethylgallium (TMG), triethylgallium (TEG), dimethyl selenide, tellurium tetrachloride, trimethylaluminum (TMAl), triethylaluminum (TEAl), NH3, AsH3, and PH3, in particular (3-aminopropyl)triethoxysilane, N-sec-butyl(trimethylsilyl)amine, chloropentamethyldisilane, tetramethylsilane, silicon tetrabromide, silanol, silicon tetrachloride, tris(tert-butoxy)silanol, SiH4, tetramethyl germanium, triethyl germanium hydrolide, triphenyl germanium hydride, triphenyl germanium hydride, tetramethyl germanium, tributyl germanium hydride, triethyl germanium hydride, trimethyl indium (TMin), trimethyl indium (TEIN), trimethyl gallium (TMG), triethyl gallium (TEG), dimethyl selenide, tellurium tetrachloride, etc. Lanthanide derivatives, more particularly (3-aminopropyl)triethoxysilane, N-sec-butyl(trimethylsilyl)amine, chloropentamethyldisilane, tetramethylsilane, silicon tetrabromide, silicon tetrachloride, tris(tert-butoxy)silanol, SiH4, tetramethylgermanium, triethylgermanium hydride, triphenylgermanium hydride, triphenylgermanium hydride, tetramethylgermanium, tributylgermanium hydride, triethylgermanium hydride,and derivatives such as triphenylgermanium hydride, more particularly SiH4, but are not limited to these.

[0029] In particular embodiments, at least one precursor compound is a metal hydride, particularly SiH4.

[0030] In particular embodiments, at least one precursor compound is an organometallic compound.

[0031] In detailed embodiments, the first gas flow includes two or more precursor compounds. Specifically, the first gas flow includes a first precursor compound and an additional precursor compound. In detailed embodiments, the additional precursor compound may be used as a dopant for the nanowire network (in a smaller amount than the primary precursor compound). The preferred dopant depends on the nanowire material being doped.

[0032] In particular embodiments, at least one precursor compound of the present invention is provided to the reaction vessel of the present invention at a flow rate of at least 0.01 mol / h, preferably at a flow rate of at least 0.05 mol / h, more preferably at least 0.10 mol / h, and even more preferably at a flow rate of about 0.03 mol / h.

[0033] Step (ii) The method for preparing a nanowire network of the present invention includes step (ii) of providing a second gas stream to a reaction vessel, said second gas stream containing metallic catalyst particles, and mixing the first and second gas streams in the reaction vessel to form a gas stream mixture.

[0034] In a particular embodiment, the second gas stream of the method of the present invention further comprises an inert gas, preferably N2.

[0035] In more particular embodiments, the second gas stream of the method of the present invention further comprises H2.

[0036] In particular embodiments, only one type of gas is used in the present invention. Specifically, the terms "first" and "second" refer to the number of streams used.

[0037] catalyst The method for preparing a network of nanowires of the present invention comprises step (ii) of providing a second gas stream containing metallic catalyst particles.

[0038] In a detailed embodiment, the metallic catalyst particles of the method of the present invention comprise one or more elements selected from Au, Ag, Cu, Fe, Ni, Ga, Co, Pt, In, and Al, particularly one or more elements selected from Au, Ni, Ag, and Cu, more particularly one or more elements selected from Au and Ag, and even more particularly Au. The metallic catalyst particles may consist of a single element or a combination (e.g., an alloy) of two or more elements. The metallic catalyst particles may be present in the second gas stream as solid particles or as liquid particles, preferably as solid particles.

[0039] In another detailed embodiment, the metallic catalyst particles of the method of the present invention further comprise one or more additional elements selected from the group 16 elements that control and / or promote nanowire growth, particularly selected from oxygen, sulfur, selenium, tellurium, and polonium, and more particularly selected from S, Se, Te, and O.

[0040] In particular embodiments, the metallic catalyst particles consist of an element selected from Au, Ag, Cu, Fe, Ni, Ga, Co, Pt, In, and Al, particularly an element selected from Au, Ag, and Cu, more particularly an element selected from Au and Ag, and even more particularly Au.

[0041] In a detailed embodiment, the metallic catalyst particles have an average diameter between 0.1 and 100 nm, preferably between 1 and 30 nm. The average diameter of the metallic catalyst particles of the present invention may be calculated from the average of values ​​obtained by measuring the diameter of more than 100 metallic catalyst particles using electron micrographs, or from size distributions obtained from different aerosol measurement techniques, such as differential electrostatic classification (DMA).

[0042] Additionally, the metallic catalyst particles may be provided without an electrical charge, or the metallic catalyst particles may be provided with an electrical charge.

[0043] The metallic catalyst particles may be provided to the reaction vessel in the form of an aerosol generated by an upstream aerosol generator. Alternatively, the metallic catalyst particles may be formed in situ by providing a precursor compound, preferably a gaseous precursor compound. In a preferred embodiment, the metallic catalyst particles are provided in the form of an aerosol.

[0044] In a detailed embodiment, the metallic catalyst particles are at least 1×10 -5 g / h, preferably at least 1 x 10 -4 g / h, more preferably at least 2 x 10 -4 g / h, more preferably at least 2.7 x 10 -4 g / h into the reactor.

[0045] Gas Stream Mixture In a detailed embodiment, the gas stream mixture of the method of the present invention is generated when the first and second gas streams contact in the reaction vessel. A mixing means may be used to mix the streams to form the gas stream mixture. If necessary, pressure and flow rates may be adjusted to ensure that the first and second streams are adequately mixed to form the gas stream mixture.

[0046] In a particular embodiment, the gas stream mixture circulates through the reaction vessel at a flow rate of at least 60 l / h, preferably at least 120 l / h.

[0047] In another detailed embodiment, the gas flow mixture has a residence time in the reaction vessel of less than 100 seconds, particularly between 0.1 and 80 seconds, more particularly between 1 and 60 seconds, even more particularly between 2 and 30 seconds, preferably between 4 and 16 seconds.

[0048] In addition to the gas stream mixture, one or more sheath streams may be introduced into the reaction vessel of the present invention, including, but not limited to, nitrogen, hydrogen, and noble gases such as helium and argon.

[0049] In the method of the present invention, at least one precursor compound is present in the gas stream mixture in a mole fraction (xi) of at least 0.005.

[0050] In particular embodiments, the at least one precursor compound is present in the gas stream mixture at a mole fraction of at least 0.006, particularly at least 0.01, more particularly at least 0.015, and even more particularly between 0.01 and 0.5, preferably about 0.02. In the context of the present invention, mole fraction is expressed as the amount of a component (in moles) divided by the total amount of all components (also expressed in moles).

[0051] In particular embodiments, at least one precursor compound of the present invention is at least 0.1×10 -4 Concentration in mol / l, specifically at least 1 × 10 -4 at a concentration of at least 1.5 × 10 mol / l -4 at a concentration of at least 2 × 10 mol / l, more precisely -4 It is present in the gas stream mixture at a concentration of mol / l.

[0052] In a detailed embodiment, the gas stream mixture includes H2.

[0053] In one embodiment, the gas stream mixture of the present invention comprises: at least one precursor compound; - at least a sheath gas such as nitrogen, hydrogen and / or a noble gas; metallic catalyst particles; Includes:

[0054] In one embodiment, the gas stream mixture of the present invention comprises: at least one precursor compound; - at least a sheath gas such as nitrogen, hydrogen and / or a noble gas; metallic catalyst particles; It consists of:

[0055] In a preferred embodiment, the gas stream mixture of the present invention comprises: - precursor compounds such as SiH4; - sheath gases or gas mixtures such as nitrogen, hydrogen, noble gases, or combinations thereof; metallic catalyst particles such as gold particles; It consists of:

[0056] reaction vessel In a particular embodiment, the reaction vessel used in the process of the present invention is a gas reaction vessel, preferably a cylindrical reaction vessel, more preferably a ceramic or metallic cylindrical reaction vessel, even more preferably a stainless steel cylindrical reaction vessel such as a tube.

[0057] According to the method of the present invention, the first and second gas streams are mixed in a reaction vessel.

[0058] In particular embodiments, the temperature inside the reactor vessel is uniform, particularly uniform within 50 degrees along the reactor tube, more particularly uniform over 80 cm from the high temperature zone, particularly uniform between 30 and 50 cm of the high temperature zone.

[0059] In the process of the present invention, the temperature in the reaction vessel is at least 200°C, preferably at least 400°C, more preferably at least 500°C.

[0060] In a detailed embodiment, the temperature in the reaction vessel is in the range of 200-800°C or at least 801°C, at which the precursor compound is decomposable, preferably the temperature is in the range of 200-800°C or 801-3000°C, more preferably the temperature is in the range of 300-800°C or 801-2000°C.

[0061] In a detailed embodiment, the temperature in the reaction vessel is in the range of 200 to 800°C, preferably the temperature is in the range of 300 to 700°C, more preferably 400 to 650°C, and even more preferably about 600°C.

[0062] In a detailed embodiment, the pressure in the reaction vessel is between 500 mbar and 20,000 mbar (50,000 Pa and 2,000,000 Pa), preferably between 900 mbar and 3,000 mbar (90,000 Pa and 300,000 Pa).

[0063] In particular embodiments, the temperature within the reaction vessel is achieved by any suitable heating means known in the art, preferably by plasma, arc discharge, resistance heating, hot wire heating, torch heating, or flame heating means, more preferably by resistance heating, hot wire heating, torch heating, or flame heating means.

[0064] Growth of nanowire networks In the methods of the present invention, at least one precursor compound decomposes under temperature conditions in a reaction vessel and is grown on the metallic catalyst particles by a vapor-liquid-solid (VLS) process and / or a chemical vapor deposition (CVD) process to form a network of nanowires. In particular embodiments, the nanowires are grown while in the gas flow mixture (i.e., they are aerosolized). In particular embodiments, at least one precursor compound decomposes under temperature conditions in a reaction vessel and is grown on the metallic catalyst particles by a floating catalyst chemical vapor deposition (CVD) process to form a network of nanowires.

[0065] If necessary, one or more sheath flows may be introduced into the reaction vessel, particularly between the gas flow mixture and the wall of the reaction vessel.

[0066] By selecting the appropriate precursor compounds, gas flow, temperature, pressure, and metallic catalyst particles, nanowires can be grown axially or radially, or in a combination of these two growth modes; preferably, growth occurs in the axial direction, and more preferably, growth occurs in the 110 direction, particularly in the case of Si nanowires.

[0067] Nanowire growth may begin with catalytic decomposition of at least one precursor compound on the surface of metallic catalyst particles and nucleation of nanowires on the surface of the metallic catalyst particles. After nucleation, the nanowires may undergo directional growth to form elongated objects, i.e., nanowires. Growth may occur via vapor-liquid-solid (VLS) and / or chemical vapor deposition (CVD) processes. Concurrently, the nanowires reach a critical concentration and aggregate to form a nanowire network within the reactor. Thus, the method of the present invention is a continuous aggregation process. Preferably, a gas mixture carrying the metallic catalyst particles flows through the reactor, and the nanowire network flows throughout the length of the reactor. In one embodiment, the nanowire network comprises hollow nanowires, such as nanotubes. In one embodiment, the nanowire network comprises hollow and solid nanowires, such as nanotubes. In another embodiment, the nanowire network comprises hollow nanowires, such as nanotubes.

[0068] In the context of the present invention, the term chemical vapor deposition (CVD) is understood as a process in which one or more volatile precursor compounds react and / or decompose on a catalyst surface to produce one-dimensional structures, such as nanowires. The catalyst particles may be suspended in the gas phase and are generally referred to as suspended catalysts. The particles may be in a molten or solid state and may contain additional elements that control and / or promote nanowire growth, as described herein above. These additional elements may include group 16 elements, such as S, Se, Te, or oxygen. The precursors may also partially decompose on the reactor surface.

[0069] In a detailed embodiment, the method for preparing a network of nanowires of the present invention comprises preparing a nanowire network of at least 1×10 -7 Specifically, at least 1 × 10 -6 More specifically, at least 2 × 10 -6 The aerogelation is carried out under the following parameters:

[0070] In the context of the present invention, the expression "aerogelation parameter" is understood as the product of the average aspect ratio (length / diameter) of the nanowires and the volume concentration (vc (volume of nanowires / volume of reactor)).

[0071] In the context of the present invention, the expression "vapor-liquid-solid" (VLS) method is a mechanism for growing one-dimensional structures, e.g., nanowires, from chemical vapor deposition by direct adsorption of a gas (i.e., at least one precursor compound in the gas phase) onto liquid catalyst particles that can rapidly adsorb the vapor to supersaturation levels, from which crystal growth can occur from nucleation seeds at the gas-liquid-solid interface.

[0072] In particular embodiments, the nanowire network of the present invention is formed while present in the gas flow mixture (in the reaction vessel), and in particular, a network of nanowires in which the nanowires are aggregated (i.e., the nanowires are joined, entangled, connected, or fused together) is obtained at the outlet of the reaction vessel of the present invention.

[0073] In particular embodiments, the nanowire networks of the present invention are produced as a continuous process. Alternatively, the nanowire networks may be produced individually. In preferred embodiments, the nanowire networks of the present invention are produced continuously.

[0074] In particular embodiments, the method further comprises collecting the nanowire network on a substrate, preferably the substrate is a filter, more preferably a vacuum filter. In even more particular embodiments, the method further comprises densifying the nanowire network, preferably by using a solvent or a mixture of solvents, more preferably an organic solvent or a mixture of organic solvents, even more preferably a solvent or a mixture of solvents containing an alcohol group, even more preferably by using isopropanol.

[0075] In particular embodiments, the nanowire networks of the present invention are produced at a rate of at least 0.01 g / h, preferably at a rate of at least 0.02 g / h, more preferably at a rate of at least 0.05 g / h, and even more preferably at a rate of about 0.1 g / h.

[0076] In another detailed embodiment, the nanowire network of the present invention is produced at a rate of 0.01 g / h to 10 g / h, preferably at a rate of 0.02 g / h to 5 g / h, more preferably at a rate of 0.05 g / h to 1 g / h, and even more preferably at a rate of 0.09 g / h to 1 g / h.

[0077] Nanowire Network One aspect of the present invention is directed to a network of nanowires obtainable by the method of the present invention in any of the detailed embodiments thereof, wherein the aspect ratio (length / diameter) of the nanowires of the network of nanowires is at least 130.

[0078] In a detailed embodiment, the nanowires of the nanowire network of the present invention form a mesh, and preferably the nanowires of the nanowire network are bonded, entangled, connected, fused, or interlocked with one another, preferably bonded, entangled, connected, or fused, and more preferably form junctions between them. In one embodiment, the mesh comprises aggregates of nanowires. In a detailed embodiment, the mesh is free-standing.

[0079] In a detailed embodiment, the nanowire network is free-standing. In the context of the present invention, the term "free-standing" refers to a structure that is not supported by another body or structure, e.g., a substrate. In one embodiment, the nanowire network does not include an additional phase, such as an additional matrix or binder. In an alternative embodiment, the nanowire network is present in the nanowires.

[0080] In particular embodiments, the nanowires of the networks of the invention are agglomerated, particularly strongly agglomerated, particularly they are strongly agglomerated by secondary forces such as van der Waals forces, permanent dipoles, hydrogen bonds, and / or covalent bonds, entanglements, and other forms of mechanical interlocking. By strongly agglomerated, in the context of the present invention, it is implied that the material forms a solid object and that the nanowires comprising the network cannot be easily dispersed without resorting to sonication, stirring, cutting, or similar methods.

[0081] In a particular embodiment, the network of nanowires of the present invention is a continuous network, which in the context of the present invention is understood as a non-discrete percolated network.

[0082] In a particular embodiment, the nanowire network of the present invention is an aerogel, i.e., a low density, preferably 10 -2 g / cm 3 less than, preferably 10 -3 g / cm 3 less than, more preferably 10 -4 g / cm 3 less than, more preferably 10 -5 g / cm 3 In particular embodiments, the nanowire networks of the present invention are solid materials with a density of at least 0.001 g / cm 3 , specifically at least 0.01 g / cm 3 It has a density of

[0083] In more particular embodiments, the nanowire networks of the present invention are densified, particularly by mechanical, solvent addition, electromagnetic, or similar methods.

[0084] In particular embodiments, the nanowires of the networks of the present invention have an average aspect ratio (length / diameter) of at least 10, preferably at least 100, more preferably at least 110, more preferably at least 120, even more preferably at least 130, even more preferably at least 135, even more preferably at least 140, more preferably at least 150, even more preferably at least 200.

[0085] In more particular embodiments, the nanowires of the networks of the invention have an average aspect ratio (length / diameter) between 1 and 1000, particularly between 100 and 800, and even more particularly between 120 and 700. The average aspect ratio of the nanowires of the networks of the invention may be calculated from the average of values ​​obtained by measuring the dimensions of a number of nanowires (e.g., more than 100) using electron microscopy.

[0086] In particular embodiments, the average length of the nanowires of the networks of the invention is at least 1 micron, particularly at least 2 microns, preferably at least 3, 4, or 5 microns, more preferably at least 10 microns. In particular embodiments, the average length of the nanowires of the networks of the invention is between 1 and 30 microns, preferably between 2 and 20 microns, more preferably between 3 and 15 microns. The average length of the nanowires of the networks of the invention may be calculated from the average of values ​​obtained by measuring the length of more than 100 nanowires using electron microscopy.

[0087] In particular embodiments, the nanowire networks of the present invention have a porosity of less than 99.9%, particularly less than 99%, more particularly less than 97%, and even more particularly less than about 96%.

[0088] In another detailed embodiment, the nanowire network of the present invention has a porosity of less than 90.0%.

[0089] In alternative embodiments, the nanowire networks of the present invention have a porosity of between 99.9% and 30%, particularly between 50% and 98%, more particularly between 60% and 97%, and even more particularly about 96%.

[0090] The porosity of a nanowire network has been measured using methods known in the art, for example, by optical and / or electron microscopy, typically by determining the volume of a sample and weighing it, and the porosity is then calculated by comparison with the theoretical density of a monolithic crystal of the same material as the nanowire, as known in the art.

[0091] In particular embodiments, the nanowires of the nanowire network of the present invention are made of GaAs, InP, GaP, Ga x In 1-x As y P 1-y , Al x Ga 1-x As y P 1-y , GaSb, Gax In 1-x As y Sb 1-y , GaN, InN, AlN, Al z Ga x In 1-x-z N, Si, SiC, Ge or Si x Ge 1-x , SiO x , TiO x , ZnO x , CdS, Ta x , MoS y , W.S. y , MoTe y , TaSe y , NbSe y , NiTe y , BN, Bi z Te y , BP, Cu, Pt, CoO x , MnO x , CuO x , Li x Mn y O, Li x Ni y Mn z O, Ni x wherein 0≦x≧1, 0≦y≧1, and 0≦z≧1, and preferably Si, SiC, Ge, or Si x Ge 1-x , and SiO x wherein 0≦x≧1, and more preferably Si, Ge or Si x Ge 1-x , and SiO x where 0≦x≧1, more preferably comprising Si or Ge, and even more preferably comprising Si. In particular embodiments, the nanowires of the nanowire network of the present invention further comprise a coating, preferably an inorganic coating or a carbon coating.

[0092] In another detailed embodiment, the nanowires of the nanowire network of the present invention are made of GaAs, InP, GaP, Ga x In 1-x As y P 1-y , Alx Ga 1-x As y P 1-y , GaSb, Ga x In 1-x As y Sb 1-y , GaN, InN, AlN, Al z Ga x In 1-x-z N, Si, SiC, Ge or Si x Ge 1-x , SiO x , TiO x , ZnO x , CdS, Ta x , MoS y , W.S. y , MoTe y , TaSe y , NbSe y , NiTe y , BN, Bi z Te y , BP, Cu, Pt, CoO x , MnO x , CuO x , Li x Mn y O, Li x Ni y Mn z O, and Ni x wherein 0≦x≧1, 0≦y≧1, and 0≦z≧1, and preferably Si, SiC, Ge, or Si x Ge 1-x , and SiO x where 0≦x≧1, and more preferably consisting of at least one material selected from Si and Ge, and even more preferably consisting of Si. In another detailed embodiment, the nanowires of the nanowire network of the present invention consist of at least one material selected from Si and Ge and a coating, preferably an inorganic or carbon material.

[0093] In particular embodiments, the nanowire networks of the present invention have a density of at least 0.01 g / cm 3 , specifically at least 0.05 g / cm 3of, more particularly at least 0.075 g / cm 3 of, more particularly at least 0.080 g / cm 3 Preferably at least 0.015 g / cm 3 of, more preferably at least 0.020 g / cm 3 , more preferably about 0.128 g / cm 3 It has a volume density of

[0094] In a detailed embodiment, the nanowire network of the present invention has a density of 0.01 g / cm 3 and 0.2 g / cm 3 Between, specifically 0.07g / cm 3 and 0.30 g / cm 3 The volume density of the nanowire networks of the present invention may be calculated from any experimental technique known in the art, in particular, it is determined from the area density and thickness of a sample of the nanowire network.

[0095] In particular embodiments, the nanowires of the nanowire networks of the present invention are entangled, preferably physically entangled.

[0096] In particular embodiments, the nanowire networks of the present invention are networks comprising nanowires. In particular embodiments, the nanowires forming the network can have the same or different properties. In more particular embodiments, the nanowires contained in the network have different compositions and / or aspect ratios.

[0097] In particular embodiments, the nanowires of the network of nanowires are hollow (i.e., they are nanotubes), and preferably they are nanotubes. In more particular embodiments, the hollow nanowires are made of Si, SiC, Ge, or Si. x Ge 1-x , and SiO x where 0≦x≧1, and more preferably made of at least one material selected from Si and Ge, and even more preferably made of Si.

[0098] In particular embodiments, the nanowire networks of the present invention further comprise metallic catalyst particles for use in the methods of the present invention.

[0099] In particular embodiments, the nanowires of the network of nanowires of the present invention further comprise a coating, in particular an inorganic coating or a carbon coating, more preferably a carbon coating.

[0100] In particular embodiments, the nanowire networks of the present invention further comprise a coating, particularly an inorganic coating or a carbon coating, more preferably a carbon coating.

[0101] In another detailed embodiment, the nanowire networks of the present invention can be chemically functionalized by a gas phase process, a liquid phase process, an annealing process, or an irradiation process. In a detailed embodiment, the chemical functionalization of the nanowires is carried out during the synthesis process or in an additional step.

[0102] In particular embodiments, the nanowires of the nanowire network of the present invention further comprise a labeling or marking element or compound, said labeling element or compound providing traceability of the nanowires. In particular embodiments, labeling or marking of the nanowires is carried out during the synthesis process or in an additional step after said synthesis.

[0103] In particular embodiments, the nanowires of the nanowire networks of the present invention are predominantly aligned.

[0104] In particular embodiments, the nanowires of the nanowire networks of the present invention are drawn, stretched, or subjected to electromagnetic or electrochemical methods to align the nanowires.

[0105] In particular embodiments, the nanowire networks of the present invention further comprise particles, preferably amorphous particles, more preferably amorphous spherical particles.

[0106] In particular embodiments, the nanowires of the nanowire networks of the present invention are crystalline.

[0107] In one embodiment, the nanowire network of the present invention comprises a crystalline phase and an amorphous phase, preferably the crystalline phase is present in at least 50 wt%, more preferably at least 75 wt%, and even more preferably at least 90 wt% of the total weight of the network, and even more preferably the crystalline phase comprises crystalline nanowires and the amorphous phase comprises amorphous particles, preferably amorphous spherical particles.

[0108] In one embodiment, the nanowire network of the present invention comprises at least 50 wt%, preferably at least 75 wt%, more preferably at least 90 wt% crystalline nanowires by total weight of the network.

[0109] In another detailed embodiment, the nanowire network of the present invention consists of nanowires.

[0110] In one embodiment, the nanowire networks of the present invention have an energy-to-break value of at least 0.05 J / g, preferably between 0.1 and 0.5 J / g, as measured by mechanical tensile testing of nanowire network samples using conventional mechanical testing equipment as known in the art.

[0111] In one embodiment, the nanowire network of the present invention has a specific tensile strength greater than 0.5 MPa / SG, preferably greater than 0.8 MPa / SG, and more preferably greater than 1 MPa / SG. Specifically, specific tensile strength values ​​are in units of MPa / SG, where SG is g / cm. 3"Specific tensile strength" refers to the specific gravity, numerically equivalent to the density of the nanowire network, in units of . Specific tensile strength may be measured by any tensile testing technique known in the art, for example, by mechanical tensile measurement of a sample of the nanowire network using a Textechno Favimat tensile tester at a strain rate of 10% / min and preferably with a gauge length of 5 mm.

[0112] nonwoven materials Another aspect of the present invention is directed to a nonwoven material comprising a network of nanowires as defined in any of the detailed embodiments of the present invention, in which the nonwoven material of the present invention comprises one or more layers of the network of nanowires of the present invention.

[0113] In another detailed embodiment, the nonwoven material of the present invention is a nonwoven fabric, preferably a unidirectional nonwoven fabric.

[0114] In another detailed embodiment, the nanowires of the network of nanowires of the nonwoven material of the present invention are oriented in a single direction, preferably in a single parallel direction.

[0115] In another detailed embodiment, the nonwoven material of the present invention is a nonwoven fabric in which the nanowires of the network of nanowires are oriented in a single direction, preferably in a single parallel direction.

[0116] In another detailed embodiment, the nonwoven material of the present invention is spun.

[0117] In another detailed embodiment, the nonwoven materials of the present invention can be chemically functionalized by gas phase, liquid phase, annealing, or irradiation processes that modify the surface chemistry of the nanowires.

[0118] use Another aspect of the present invention is directed to the use of the nanowire networks of the present invention in electronic devices, micromechanical systems, optoelectronic devices, wearable devices, insulators, sensors, electrodes, catalysis, structural components, batteries, flexible devices, radiation absorbing materials, and transparent devices.

[0119] Another aspect of the present invention is directed to the use of the nonwoven materials of the present invention in electronic devices, micromechanical systems, optoelectronic devices, wearable devices, insulators, sensors, electrodes, catalysis, structural components, batteries, flexible devices, radiation absorbing materials, and transparent devices.

[0120] In one embodiment, the present invention is directed to the use of a network of nanowires of the present invention or a nonwoven material of the present invention in a battery, particularly in an electrode such as an anode or cathode, a separator, and / or a current collector of a battery.

[0121] In one embodiment, the present invention is directed to the use of a network of nanowires of the present invention or a nonwoven material of the present invention as an electrode, preferably as an anode in a lithium battery.

[0122] electrode Another aspect of the present invention is directed to an electrode comprising the inventive nanowire network or the inventive nonwoven material in any of the detailed embodiments of the present invention, and optionally an electrical connection or current collector, preferably comprising a conductive wire or current collector, wherein the electrical connection and the nanowire network are electrically connected. In one embodiment, the electrode comprises the inventive nanowire network. In more detailed embodiments, the electrode is an anode.

[0123] The present authors have realized that the mechanical properties imparted by the nanowire network obviate the use of reinforcing additives (e.g., polymeric binders) in the electrodes, enabling methods for processing or integrating such electrodes without the need for traditionally used solvents or other forms of dispersion.

[0124] Pharmaceutical Composition One aspect of the present invention is directed to a pharmaceutical composition comprising a network of nanowires according to any one of claims 10 to 25 or a nonwoven material according to claim 26, preferably as a pharmaceutically acceptable excipient. [Example]

[0125] The present invention is illustrated by the following examples, which are not intended to limit the scope of the invention in any way.

[0126] Example 1 Nanowire networks, including silicon (Si) nanowires, were produced by decomposing a Si precursor in the presence of catalytic nanoparticles suspended in the gas stream within the reactor.

[0127] The first gas stream delivered SiH precursor (2 g / h) to the reaction vessel in a flow of H (200 specific cubic centimeters / minute). Simultaneously, the second gas stream introduced a pre-synthesized catalytic gold nanoparticle aerosol into the reaction vessel in a flow of N (1 specific liter / minute) as the main carrier gas. The first and second streams were then mixed to form a gas flow mixture.

[0128] The SiH precursor was added in the gas stream mixture at a mole fraction of 0.02 (expressed as the amount of precursor in moles divided by the total amount of all components in the mixture also expressed in moles) and in the reaction vessel at a mole fraction of 2.4 × 10 -4 The reaction vessel used was a metal reaction tube in a tubular furnace.

[0129] As the gas flow mixture entered the high-temperature zone of the reactor (approximately 600 °C), the Si precursor decomposed and associated with the catalyst particles. Si nanowires grew rapidly within the reactor and were suspended in the gas flow. The average length of the nanowires was at least 4 microns. The average diameter and aspect ratio of the nanowires were obtained from numerous measurements performed by image analysis of scanning electron micrographs at high magnification. The length of the nanowires was calculated from the product of the diameter and the aspect ratio.

[0130] The nanowires entangled and interacted with each other within the reaction vessel to form a highly porous solid (a nanowire network), similar to a spider web or aerogel (see Figure 3), associated through the strong surface interactions between the nanowires. The residence time in the reaction zone was less than 40 seconds. The synthesized network material was recovered by spinning or drawing as a unidirectional nonwoven fabric.

[0131] The synthesized nanowire material network was free-standing (see Figure 4) and had sufficient mechanical stability to withstand handling under conditions relevant for further processing. As shown in Figure 5, the resulting material was flexible enough to withstand reversible bending to a radius of curvature of several millimeters (see Figure 5). The nanowire network had a molecular weight of 0.09 g / cm. 3 The nanowire network exhibited a low volume density of 1×10 and a porosity of approximately 96.0%. -1 produced at rates higher than g / h.

[0132] Mechanical testing of the nanowire networks was performed. Specifically, tensile tests were performed at a strain rate of 10% / min using a Tectechno Fabimat tensile tester. Sample dimensions were determined from optical micrographs of each sample. The width and thickness of the nanowire network samples were 0.6 mm and 25 microns, respectively. The volume density was then determined from the areal density and thickness of the samples. The areal density was determined by weighing a typical sample of the nanowire network, while the dimensions can be determined by direct observation using optical and / or electron microscopy.

[0133] Samples that broke at the gripper joint were discarded, leaving a total of 36 samples tested: 23 at a 5 mm gauge length, 5 at a 2 mm gauge length, and 8 at a 1 mm gauge length. No significant differences in tensile strength were observed at smaller gauge lengths. Data were corrected for machine compliance obtained from tensile testing of commercial polyaramid fibers. The stress-strain curves in the main text are for samples with a 5 mm gauge length. Tensile energy-to-break values ​​are shown in Table 1. The data shown in Table 1 were calculated from the best 10 measurements, which provide clear evidence of true fracture, as opposed to fracture induced by gripping defects introduced into the sample during processing. Density ratios were calculated assuming a maximum density corresponding to a hexagonally close-packed bundle of solid rods, each with the theoretical bulk density of this material. Specifically, specific tensile strength values ​​are in units of MPa / SG, where SG is g / cm. 3 This refers to the specific gravity, numerically equivalent to the density of the nanowire network, in units of . [Table 1]

[0134] Figure 6 shows the mechanical test results for rectangular fabrics of Si nanowire samples. Specifically, Figure 6 shows the stress-strain curves for samples with a 5 mm gauge length. These samples exhibited high fracture energy values ​​due to elastic-plastic deformation and correspondingly high ductility. The nanowire network exhibited a large ductility value of approximately 3%. Additionally, the fracture energy value normalized to density was 0.18 ± 0.1 Jg. -1 It was.

Claims

1. i. providing a first gas stream to a reaction vessel, the first gas flow comprising at least one precursor compound comprising at least an element selected from Si and Ge, the precursor compound being a metal hydride or an organometallic compound; ii. providing a second gas stream containing metallic catalyst particles consisting of one element selected from Au, Ag, Cu, Fe, Ni, Ga, Co, Pt, In, and Al into the reaction vessel, and mixing the first and second gas streams in the reaction vessel; at least one precursor compound, at least a sheath gas selected from nitrogen, hydrogen and / or a noble gas, forming a gas flow mixture consisting of: the at least one precursor compound is present in the gas stream mixture at a mole fraction (xi) of at least 0.01; the temperature in the reaction vessel is in the range of 200 to 800°C, or is at least 801°C; the at least one precursor compound decomposes under the temperature in the reaction vessel and grows on the metallic catalyst particles by vapor-liquid-solid (VLS) and / or chemical vapor deposition (CVD) to form a network of nanowires; A method for preparing a network of nanowires, wherein the nanowires of the network of nanowires are made from a solid material or are hollow.

2. The method of claim 1 , wherein the at least one precursor compound comprises Si.

3. 3. The method of claim 1, wherein the at least one precursor compound is a metal hydride.

4. The at least one precursor compound may be (3-aminopropyl)triethoxysilane, N-sec-butyl(trimethylsilyl)amine, chloropentamethyldisilane, tetramethylsilane, silicon tetrabromide, silicon tetrachloride, tris(tert-butoxy)silanol, SiH ４ 2. The method of claim 1, wherein the germanium hydride is selected from the group consisting of tetramethyl germanium, triethyl germanium hydride, triphenyl germanium hydride, triphenyl germanium hydride, and tributyl germanium hydride.

5. 5. The method according to claim 1, wherein the metallic catalyst particles consist of one element selected from Au, Ag, and Cu.

6. 6. The method of claim 1, wherein the metallic catalyst particles are gold particles.

7. The gas stream mixture is H ２ 7. The method of claim 1, comprising:

8. 8. The method of claim 1, wherein the network of nanowires is produced at a rate of at least 0.01 g / h.

9. 9. The method according to any one of claims 1 to 8, wherein the temperature in the reaction vessel is in the range of 300 to 800°C, or 801 to 3000°C.

10. 10. The method of claim 1, wherein the at least one precursor compound is present in the gas stream mixture at a molar fraction (xi) between 0.01 and 0.

5.

11. 11. A nanowire network obtainable by the method of any one of claims 1 to 10, wherein the nanowires of said nanowire network have an aspect ratio of at least 130, wherein said nanowire network has a porosity of 60-97%, wherein said nanowires of said nanowire network are made of solid material or are hollow, and wherein said nanowires comprise Si, SiC, Ge or Si x Ge 1-x and SiO x , where 0≦x≧1 and x is either greater than or equal to 0 or greater than or equal to 1.

12. The nanowire network of claim 11 , wherein the nanowire network is free-standing.

13. 13. The network of nanowires of claim 11 or 12, wherein the nanowires have an average aspect ratio of at least 150.

14. 14. The network of nanowires of claim 11, wherein the nanowires have an average length of at least 1 micron.

15. The nanowires are made of Si, SiC, Ge or Si ｘ Ge １－ｘ , and SiO ｘ 15. The nanowire network of claim 11, wherein 0≦x≧1, and x is either greater than or equal to 0, or greater than or equal to 1.

16. 16. The network of nanowires of claim 11, wherein the nanowires form a mesh.

17. The network has a density of at least 0.075 g / cm ３ 17. The network of nanowires of claim 11, having a volume density of

18. 18. The network of nanowires of claim 11, having an energy-to-break value of at least 0.05 J / g.

19. 19. The network of nanowires of any one of claims 11 to 18, wherein the nanowires are made of Si or Ge and the nanowires form a mesh.

20. 20. A nonwoven material comprising a network of nanowires as defined in any one of claims 11 to 19.

21. 21. An electrode comprising a network of nanowires according to any one of claims 11 to 19 or a nonwoven material according to claim 20.

22. Use of the network of nanowires of any one of claims 11 to 19 or the nonwoven material of claim 20 in electronic devices, micromechanical systems, optoelectronic devices, wearable devices, insulators, sensors, electrodes, catalytic reactions, structural components, batteries, flexible devices, radiation absorbing materials, and transparent devices.

23. 21. Use of the network of nanowires according to any one of claims 11 to 19 or the nonwoven material according to claim 20 in an electrode, separator and / or current collector of a battery.

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