TW201321300A - Metal nanostructure and preparation thereof - Google Patents

Abstract

Nanoporous polystyrene matrix can be fabricated from the self-assembly of degradable block copolymer, polystyrene-b-poly(L-lactide) (PS-PLLA), followed by the hydrolysis of PLLA blocks. Metal is deposited in nanopores of the PS matrix using the nanoporous PS as a template via electroless plating. After subsequent UV degradation of the PS matrix, metal in the nanopores remains, yielding a metal nanostructure. The metal nanostructure may be a gyroid nanostructure, helical nanostructure or columnar nanostructure.

Description

Metal nano structure and preparation method thereof

The present invention relates to a metal nanostructure comprising a metal nanostructure block which does not depend on a support and which itself can be self-standing, and a large area formed on a substrate, for example 0.5 cm x 0.5 cm The above metal nanostructure film. The metal can be nickel, gold, silver, copper or other metals. The metal nanostructure can be applied to supercapacitors, high energy density battery packs, hydrogen storage containers, electromagnetic composites, surface-enhanced Raman spectroscopy, antimicrobial scaffolding, filtration and desalting, and lightweight Structures, heat sinks, ultrahigh electromagnets, and magnetic media.

U.S. Patent No. 7,135,523 B2 discloses a method for making a series of nanoscale microstructures comprising a helical microstructure and a cylindrical microstructure. The method comprises the steps of: (1) forming a palm-shaped block copolymer comprising a plurality of palmar first polymer segments and a second polymer segment, wherein the palmar first polymer segments have a To a volume fraction of 49%; (2) causing phase separation of the palm block copolymer. In a preferred embodiment, the palm block copolymer is a poly(styrene)-poly(L-lactic acid) (PS-PLLA) palm block copolymer, and the copolymerization method is a living copolymerization method. And comprising the steps of: (a) mixing styrene with BPO and 4-OH-TEMPO to form a polystyrene terminated with 4-hydroxy-TEMPO-; and (2) making the 4-hydroxy-TEMPO- The terminal polystyrene and [(η ₃ -EDBP)Li ₂ ] ₂ [(η ₃ -"Bu)Li(0.5Et ₂ O)] ₂ and L-lactic acid are in an organic solvent, preferably CH ₂ Cl ₂ , mixed to form the poly(styrene)-poly(L-lactic acid) palm block copolymer. Transmission electron microscopy (TEM) and small angle scattering X-ray (SAXS) studies show that when the poly(L-lactic acid When the volume fraction is about 35 to 37%, a nano-scale helical microstructure having a pitch of 43.8 nm and a diameter of 34.4 nm is observed.

U.S. Patent Application No. 2004/0265548 A discloses a nanopattern template used in the manufacture of a nanoscale structure. The nano pattern template comprises a nano film structure having a periodic arrangement and a porous form, the nanoporous film being made by a method comprising the steps of: (a) preparing by a block copolymerization method comprising the first And a block copolymer of the second polymer segment, the first and second polymer segments being mutually incompatible; (b) a condition for enabling the first polymer segment to form a periodic alignment pattern Forming a film underneath; and (c) selectively degrading the first polymer segment such that the film forms a nanoporous material having a periodic arrangement. In a preferred embodiment, the block copolymer is a poly(styrene) -b -poly(L-lactic acid) (PS-PLLA) palm block copolymer, the first polymer being poly(L- Lactic acid), and the second polymer is polystyrene. The experimental results show that the first polymer segments can form a hexagonal closest packed cylindrical shape perpendicular to the direction of the film surface. After the first polymer segment is selectively degraded by hydrolysis, a film having a nanometer-sized hexagonal closest packed nano-scale cylindrical channel is obtained by controlling the molecular weight and volume fraction of the first polymer. The size and spacing of the apertures can be controlled.

U.S. Patent Application No. 2006/0124467 A discloses a metal nanodot array and a method of manufacturing the same. The film of the block copolymer is desorbed onto a conductive substrate. The block copolymer comprises a first polymer and a second polymer segment, wherein the first polymer segments have a periodic regular arrangement. The first polymer segments are selectively degraded to form a nanopattern template comprising periodically aligned nanochannels. Metal is deposited by plating in a nanochannel that exposes the conductive substrate, thereby forming an array of metal nanodots.

Rong-Ming Ho et al., in the article entitled "Helical Nanocomposites from Chiral Block Copolymer Templates", J. AM. CHEM. SOC. 2009, 131, 1356-1357, discloses a block copolymer that combines decomposability. Three-dimensional array of spiral nanocomposites prepared by self-assembly and solution-gel chemistry. The self-assembly behavior of the PS-PLLA palm block copolymer is first performed to form a PS porous block having a nanopore via hydrolysis degradation of the PLLA segment. Using this block as a template, a solution-gel reaction was carried out in the template by the concept of a nanoreactor to produce a nanostructured composite having a helical structure. The SiO ₂ nanohelix was obtained after the PS template was degraded under UV exposure.

A method of making a nanomaterial using a block copolymer template is disclosed in U.S. Patent Application Serial No. 2011/0003,069. The block copolymer block is prepared by using a block copolymer obtained by polymerizing a plurality of monomers which are decomposable and non-decomposable, and after removing the decomposable portion, a block copolymer having a plurality of pores is obtained. Templates, these holes are arranged in a periodically arranged nanostructure. Combined with the concept of a nanoreactor, a composite material containing a nanostructure can be obtained by filling various filler materials such as ceramics, metals and polymers by means of a solution-gel method or electrochemical synthesis. After removing the polymer block copolymer template, a reversed-phase nanomaterial having a nanostructure can be obtained. This patent application does not disclose a specific preparation method for the metal nanostructure, nor does it have any examples.

The SiO ₂ spiral quaternary tetrahedron having an extremely low refractive index, for example, an equivalent refractive index as low as 1.1, is also disclosed in U.S. Patent Application Serial No. 13/005,637, filed on Jan. 13, 2011. The anti-reflective structure of the pentagonal trioctahedron is formed by spin coating and solvent annealing to form a thin layer of the PS-PLLA palm block copolymer, followed by the above hydrolysis, solution-gel procedure and Prepared by degradation of PS template.

The details of the disclosures in the aforementioned U.S. Patent and Patent Publications are incorporated herein by reference.

The present invention provides a metal nanostructure which may be nickel, gold, silver, copper or other metal. Preferably, the metal is nickel.

The present invention provides a metal nanostructure that is self standing. The self-standing metal nanostructure is a spiral gyro nanostructure, or a spiral nanostructure connected to each other. In one embodiment of the invention, a self-standing spiral twenty-tetrahedral nanostructure is prepared.

The present invention provides a metal nanostructure on a large area, such as 0.5 cm x 0.5 cm or more, on a substrate. The large-area metal nanostructure may be a gyroid nanostruture, a helical nanostructure, or a cylindrical nanostructure. Preferably, the large-area metal nanostructure is a helical twenty-tetrahedral nanostructure. The surface of the substrate in contact with the metal nanostructure may be a non-conductive surface or a conductive layer. Preferably, the large area metal nanostructure has a thickness of from about 100 nm to about 200 nm.

The invention also provides a method for preparing a metal nanostructure, which comprises an improved electroless plating method.

The invention also provides a device having the metal nanostructure of the invention, which is selected from the group consisting of a supercapacitor, a high energy density battery, a hydrogen storage container, an electromagnetic composite, a surface-enhanced Raman spectroscopy, Antimicrobial stents, filters, desalination devices, heat sinks, ultrahigh field electromagnets, and magnetic media.

The substrate suitable for use in the present invention is quartz, glass, polymer or semiconductor, and the surface thereof does not need to be coated with a conductive layer to form the metal nanostructure of the present invention on the surface via the improved electroless plating method of the present invention. . Preferably, the semiconductor substrate is a germanium wafer or a hafnium oxide substrate. Optionally, the glass substrate may also be an indium tin oxide (ITO) glass substrate or a carbon coated glass substrate.

A method suitable for preparing the metal nanostructure of the present invention comprises the following steps:

a) providing a nanometer porous template;

b) immersing the nanoporous template in a solution containing palladium ions;

c) removing the nanoporous template from the solution, and subsequently washing the nanoporous template with a cleaning solution;

d) immersing the washed nanoporous template in an electroless plating solution, so that the palladium ion in the nanopore of the nanoporous template is first reduced to palladium atoms, and thus the metal ion in the electroless plating solution is the palladium atom It is catalyzed and reduced to an elemental metal and filled into a nanopore of the nanoporous template, wherein the metal is nickel, gold, silver or copper.

Preferably, the method of the present invention further comprises the steps of: e) removing the nanoporous template of the elemental metal filled in step d) by using ultraviolet exposure, calcination, organic solvent, supercritical fluid or a combination thereof, leaving the The metal in the nanopore thus produces a metallic nanostructure.

If the nanoporous template of the aforementioned step a) is a self-standing nanoporous template, the step e) of the method of the invention will prepare a metal nanostructure which can stand on its own, that is, a massive metal na[iota] Rice structure. If the nanoporous template of the foregoing step a) is a film formed on the surface of a substrate, step e) of the method of the present invention will produce a large-area metal nanostructure layer attached to the surface of the substrate. By the same token, step d) of the method of the invention will produce a composite material comprising a metallic nanostructure and standing on its own, or a large-area composite layer comprising a metallic nanostructure and attached to the surface of a substrate.

The preparation of the metal nanostructure of the present invention is susceptible to failure due to blockage of the nanopores of the nanoporous template. For example, the stannous chloride used in the sensitizing process of the conventional electroless plating process forms a gel to block the nanopores; and if the distribution of palladium atoms attached to the pores is too dense, it will also be initially The reduced elemental metal is too dense to block the pores, causing the electroless plating reaction to be difficult to enter and affect the subsequent electroless plating process.

Another feature of the present invention is that the metal obtained by the conventional electroless plating formulation is amorphous, and it is required to pass through high temperature calcination to obtain a crystalline metal having better mechanical strength; however, the electroless plating of the method of the present invention utilizes "metal. The concept of nucleation growth causes the metal ions in the electroless plating solution to be reduced to the elemental state under the catalysis of palladium atoms. This elemental metal becomes the core, through the self-catalyzing process - the nascent element The metal itself is the catalytic point to cause subsequent metal ions to be reduced and stacked thereon to obtain a crystalline metal.

Preferably, the palladium ion-containing solution in step b) of the process of the invention has a palladium ion concentration of from 0.06 to 6.0 mg/ml. A solution containing 0.6 mg/ml palladium ions is used in an embodiment of the invention. Preferably, the palladium ion-containing solution further contains a surface tension modifier which promotes wetting of the template, such as a C1-C4 alcohol. Preferably, the palladium ion-containing solution further contains a dissolution promoter such as an acid which enhances dissolution of the palladium salt therein. In one embodiment of the invention, a mixture of 45 ml of ethanol and 5 ml of 1 N aqueous hydrochloric acid solution was used to dissolve 0.05 g of PdCl ₂ .

Preferably, the cleaning solution in step c) of the process of the invention is any solution which removes palladium ions from the outer surface of the nanoporous template, such as deionized water, alcohols, ethers, esters or mixtures thereof. A mixture of ethanol and water is used in an embodiment of the invention.

Preferably, the electroless plating solution in step d) of the process of the invention contains a reducing agent for reducing the palladium ions to palladium atoms. Suitable reducing agents include, but are not limited to, hydrazine, hydrazine hydroxide, formaldehyde, sodium borohydride, dimethylformamide, beta-D-glucose, ethylene glycol, sodium citrate, ascorbic acid, dimethyl碸, potassium hydrogen tartrate, methanol, ethanol, 1-propanol, 2-propanol, pyridine, poly(ethylene glycol), and ginseng (trimethyldecyloxy) decane or hydrogen.

Preferably, the nanoporous template in step a) of the method of the invention is a porous ceramic, a porous metal or a porous polymer. More preferably, the nanoporous template is a porous polymer selected from the group consisting of poly(styrene), poly(vinylpyridine) and poly(acrylonitrile), and poly(styrene) is preferred.

A method suitable for preparing a self-standing polymer nanoporous template comprising providing a palm block copolymer having a first polymer segment and a second polymer segment, wherein the first The polymer is selected from the group consisting of poly(L-lactic acid) and poly(D-lactic acid), and the second polymer is selected from the group consisting of poly(styrene), poly(vinylpyridine) and poly(acrylonitrile). a group formed by adjusting a volume fraction of the first polymer segment to the palm block copolymer, the first polymer segment forming a series of repeating nano-hexagons therein - a cylindrical, spiral or helical tetrahedral structure; and selectively degrading the first polymer segment of the palm block copolymer to form a corresponding porous nanochannel, thus obtaining a series of repeating regular arrangements The second polymer segment of the nano-scale hexagonal closest packed cylindrical, spiral or helical tetrahedral channel. In addition, the first polymer may be selected from a non-pallicate but also degradable polymer, such as a group consisting of the first polymerizable free poly(lactic acid), poly(caprolactone), and the second The polymer is selected from the group consisting of poly(styrene), poly(vinylpyridine), and poly(acrylonitrile), wherein the volume of the first polymer segment to the non-palm block copolymer is adjusted Fraction, the first polymer segment may form a series of repeating nano-scale hexagonal-cylindrical or helical tetrahedral structures therein; and selectively degrade the first polymer chain of the non-palm block copolymer The segments are formed to form corresponding porous nanochannels, thus obtaining a second polymer segment having a series of nanoscale hexagonal closest packed cylinders or helical tetrahedral channels having a repetitively regular arrangement.

A method suitable for preparing a polymeric nanoporous template on a surface of a substrate comprises: coating a palm having a first polymer segment and a second polymer segment on a substrate modified with an organic material a layer of an organic solvent solution of the block copolymer; placing the coated substrate in an environment containing a vapor of a non-selective solvent to subject the resulting coating to solvent annealing to form a second polymerization having a bulk as a host a segment of the block, and a block copolymer film layer of the first polymer segment having a series of repeating nanostructures in the body; selectively degrading the first polymer segment to form a body of the film The corresponding nanochannel in the middle. Preferably, the coating is spin coating. Preferably, the organic solvent solution has a concentration of the block copolymer of from 1.5 to 10% by weight, more preferably about 3% by weight. The organic solvent is dichlorobenzene, chlorobenzene, dichloromethane, toluene or tetrahydrofuran, etc. Preferably, the organic solvent is dichlorobenzene. Preferably, the non-priority solvent is dichloromethane or chloroform. Preferably, the coating has a thickness of from about 100 nm to about 200 nm. Preferably, the nanochannel is a helical twenty-tetrahedral nanochannel.

Preferably, the organic material for modifying the surface of the substrate is a hydroxyl-terminated polystyrene, a hydroxyl-terminated poly(vinylpyridine) or a hydroxyl-terminated poly(acrylonitrile). And more preferably, it is a hydroxyl terminated polystyrene. Preferably, the hydroxyl terminated polystyrene has a molecular weight of from 5,000 to 10,000.

Preferably, the block copolymer is a poly(styrene)-poly(L-lactic acid) palm block copolymer, the first polymer segment is poly(L-lactic acid), and the second polymer The segment is polystyrene. Preferably, the first polymer segment in the block copolymer has a volume fraction of from 36% to 50%, more preferably about 40%.

Preferably, the first polymer segment is selectively degraded by hydrolysis.

Preferably, in step e) the second polymer segment main system is removed by using an organic solvent such as tetrahydrofuran (THF) or toluene.

Preferably, in step e) the nanoporous template is removed by exposure to ultraviolet light, such as a wavelength of 254 nm and an intensity of 3 mW/cm ² .

The poly(styrene)-poly(L-lactic acid) (PS-PLLA) palm block copolymer and a process for the preparation thereof are disclosed in U.S. Patent No. 7,135,523 B2, which form a nano-scale microstructure, which is of the nano-scale The microstructure includes a spiral microstructure and a cylindrical microstructure according to the volume fraction of PLLA. U.S. Patent Application No. 2004/0265548 A discloses a nanopattern template for use in the manufacture of nanoscale objects in which a spin-coated PS-PLLA layer on a substrate is hydrolyzed such that PLLA is removed. Periodically arranged nanoporous patterns. Rong-Ming Ho et al., in the article entitled "Helical Nanocomposites from Chiral Block Copolymer Templates", J. AM. CHEM. SOC. 2009, 131, 1356-1357, additionally discloses the disclosure of U.S. Patent No. 7,135,523 B2. The nano-scale microstructure of PS-PLLA was prepared by the solution-gel chemistry to prepare a three-dimensional array of helical nanocomposites to produce a SiO ₂ nanohelix structure. An anti-reflective structure of a SiO ₂ spiral icosahedron having an extremely low refractive index, such as an equivalent refractive index as low as 1.1, is disclosed in U.S. Patent Application Serial No. 13/005,637, filed on Jan. 13, 2011. . The anti-reflective structure is formed by spin coating and solvent annealing to form a PS-PLLA palm-shaped block copolymer layer, followed by hydrolysis to form a spiral tetrahedral channel, a solution-gel procedure and a degradation of a PS template. .

In the present invention, based on the above prior art, a chiral block copolymer is used to form a nanochannel having a different morphology as a nanoreactor, and at the same time, a novel modified electroless plating method has been developed successfully in the nai. A metal nanostructure is formed in the nanochannel of the rice reactor. The improved electroless plating method of the present invention eliminates the need for sensitization of conventional electroless plating (immersion in aqueous solution of stannous chloride), and combines activation (palladium atom-catalytic point generation) with electroless plating (reduction of metal ions). Completed in the same solution. The palladium (Pd) metal reduced in the pore first becomes the active point, and then the metal ion in the solution undergoes a reduction reaction at the active site to form a metal nucleus, and the metal ion in the solution is continuously sourced on the metal nucleus. Reduction to elemental metal, the process is a self-catalyzing process. Successful preparation of polymer/metal nanohybrids. In one embodiment of the present invention, a three-dimensional tomography technique of a transmission electron microscope can directly observe a templated nickel metal spiral quaternary nanostructure. A physical image of a polymer matrix. Subsequently, the polymer template can be removed by selecting an appropriate solvent, and the nickel metal spiral icosahedral nanostructure is completely retained to form a three-dimensional network metal having a high porosity (up to 62%), which is different from other nanoporous materials. A metallic material having a regularly arranged nanostructure. Through such a simple and easily industrialized electroless plating process, the inventors of the present invention can easily prepare polymer/metal nano-mixed materials of different compositions and structures, such as gold, silver, copper, etc. Metamaterials, green energy and chemical catalysis will have great potential for application.

The following examples are provided by way of example and are intended to be illustrative of the specific embodiments of the present invention. Purpose, as many modifications and variations will be apparent to those skilled in the art.

Example abbreviation:

L-LA: L-lactic acid

PS: Polystyrene

PLLA: Poly (L-lactic acid)

PS-PLLA BCP: poly(styrene)-poly(L-lactic acid) palm block copolymer

PDI: molecular weight distribution index

BCP: block copolymer

Synthesis of PS-PLLA BCP

The PS-PLLA BCP is prepared by a two-way polymerization sequence. We have previously described the synthesis of this PS-PLLA sample [Ho, RM; Chen, CK; Chiang, YW; Ko, BT; Lin, CC Adv. Mater. 2006, 18, 2355-2358]. The average molecular weight and molecular weight distribution (polydispersity) of the PS were measured by GPC. The polydispersity of the PS-PLLA was determined by GPC, and the number of L-LA repeating units was a function of the number of styrene repeating units and was determined by ¹ H NMR analysis. The average molecular weight of the PS and PLLA and the PDI of the PS-PLLA were 34000 g mol ^-1 , 27,000 g mol ^-1 and 1.26, respectively. Assuming that the densities of PS and PLLA are 1.02 and 1.248 g cm ^-3 , respectively, the volume fraction of PLLA is calculated to be f _PLLA ^v =0.39.

Sample preparation

The block sample of PS-PLLA BCP was prepared by allowing the 10 wt% dichloromethane solution of the aforementioned PS-PLLA BCP to be volatilized at room temperature to facilitate the self-assembly behavior of the copolymer, and placed at room temperature for 2 weeks before Dry in a vacuum oven at 65 ° C for 3 days. The dried sample was first heated to a maximum annealing temperature of 175 ° C and left for 3 minutes to remove the PLLA crystal residue formed during the preparation. Finally, quench to room temperature. After quenching from the ordered molten state of microphase separation at 175 ° C, the heat treated block copolymer was sliced using an ultra-microtome as a follow-up TEM observation. The results are shown in Figure 1a.

Hydrolysis of PLLA

The PLLA segment of the PS-PLLA copolymer was removed by hydrolysis by hydrolysis of the PLLA segment using a 0.5 M base solution as follows: 2 g of sodium hydroxide was dissolved in 40/60 (to A volumetric mixture of methanol/water. After 3 days of hydrolysis, the hydrolyzed sample was rinsed with a mixture of deionized water and methanol, followed by a stencil for subsequent electroless nickel plating.

Improved electroless plating method

A nanoporous PS template having interconnected curved air channels is immersed in an activation solution and stirred at room temperature for 3-4 hours. The activation solution is ethanol (45 ml), HCl (1 N, 5 ml) and PdCl ₂ ( 0.05 g) of the mixture. After the excess Pd ²⁺ covering the surface of the impregnated sample is gently washed with an ethanol/water solution, the sample filled with Pd ²⁺ in the hole is immersed in a newly prepared Ni plating bath at room temperature. The reaction is carried out. In this Ni plating bath, 0.2 g of nickel chloride (NiCl ₂ ‧6H ₂ O) was dissolved in distilled water (20 ml), ethanol (5 ml), hydrazinium hydroxide (85%, 2 ml) And a solution of ammonia (2 ml). The Pd ²⁺ ions are reduced by the hydrazine hydroxide to form a Pd cluster, and the nucleation of the Pd cluster is thus initiated. It is worth noting that the concentration of the activation solution prepared in this example is relatively low, and in the case where excess Pd ²⁺ ions are also washed away on the surface of the sample, only a small amount of Pd clusters can be produce. Next, Ni ²⁺ is catalyzed at the position of the Pd cluster and begins to be reduced to Ni. Since the electroless plating of Ni is an automatic, continuous process, Ni will continue to be generated inside the PS template until the nanochannels are completely filled with Ni. Therefore, a Ni metal network having a nanometer scale and having a well-ordered dispersion in the PS template can be produced.

PS template removal

In order to manufacture the helical tetrahedral Ni nanostructure, the PS main body of the PS/Ni spiral icosahedral nanomixer is removed by washing with tetrahydrofuran (THF), and the procedure is carried out. Stir at room temperature and atmospheric conditions for 24 hours. Thus, a nanoporous helix tetrahedral Ni having a good order nanostructure is easily obtained.

result

Fig. 1a shows a transmission electron microscope (TEM) photograph of the heat-treated block copolymer PS-PLLA prepared in this example, in which the dark portion is a PS main body dyed with RuO ₄ and a light colored portion. The copies are PLLA microdomains. The [100] projection image of this PS-PLLA determines the formation of a helical gyroid phase. In addition, the formation of the helical tetrahedral phase was also observed when the X-ray (1D SAXS) was observed at a small angle of 1D (not shown in the figure), wherein the cross-region of the (211) _gyroid surface measured by the main reflection was also observed. The interdomain spacing is approximately 40.9 nm. The 1D SAXS curve of the PS template after PLLA hydrolysis (not shown) shows that the PS template has the same curved shape as PS-PLLA, and the cross-region spacing of the (211) _gyroid of the PS template determined by the main reflection is 39.8. Nm, which is about 2.6% smaller. The porosity and specific surface area of this nanoporous PS template were analyzed by a nitrogen adsorption experiment and a Brunauer-Emmett-Teller analyzer (BET) to obtain about 37% and 97 m ² g ^{-1 , respectively} .

Fig. 1b is a TEM photograph showing the [111] projection image of the PS/Ni spiral icosahedral nanomixer prepared in this example, which is not dyed. The projection image of Fig. 1b is similar to that of Fig. 1a but The contrast is reversed, the portion of the black region is Ni, and the portion of the white region is the PS template, which means that PLLA is completely removed after the hydrolysis process, and Ni is modified by electroless plating in the nanoporous PS template. The method was successfully synthesized.

Fig. 2a shows a 3D image reconstructed from the Ni nanostructure in the PS/Ni spiral icosahedral nanocomposite prepared in this example, which is reconstructed from a set of 2D image projections through different tilt angles. Figure 2a shows a spiral twenty-tetrahedral Ni with a double continuous network within the PS body. In addition, the 1D SAXS curve of this hybrid material (not shown) has a cross-region spacing (39.8 nm (d _{(211) G} )) identical to that of the porous PS template, indicating that the porous PS template still maintains its electroless plating process. Spiral tetrahedral morphology. Figure 2b shows a field emission SEM (FESEM) image of the Ni nanostructure prepared in this example, in which PS has been removed from the PS/Ni nanomix material. Fig. 3 shows a low-magnification FESEM image of the porous spiral tetrahedral Ni, from which it can be seen that a porous material having a large area and a continuous phase can be prepared, and the micropores have precisely controllable geometry. shape. The small image in the lower right corner of Fig. 3 is a photograph of this porous spiral hexahedral Ni block, from which it can be seen that this embodiment can prepare a bulk sample having a public grading scale, no crack and standing on its own. Further, it was further confirmed by Fourier infrared (FT-IR) spectroscopy (not shown) that PS was completely removed from the PS/Ni nanomixed material.

The porosity of the porous spiral tetrahedral Ni prepared in this example is about 62% as measured by nitrogen adsorption experiments, and its specific surface area per gram is 1467 m ² mol ^-1 (25 m ² g ^{-1 ).} ). The void-free pure Ni obtained by the same modified electroless plating has an intrinsic density of about 8.0 gcm ^-3 , so the density of the porous spiral tetrahedral Ni is about 3.05 gcm ^-3 (38% relative) density).

In order to examine the crystallization characteristics of the porous helix tetrahedron Ni, we performed electronic selective diffraction (SAED) and wide-angle X-ray diffraction (XRD) experiments. Figure 4 shows the SAED pattern and Figure 2c shows Its XRD curve. The diffraction ring in Figure 4 can be identified as having a face centered cubic (fcc) Ni polycrystal while also identifying trace amounts of NiO crystals. We speculate that this NiO should be produced when Ni is exposed to air and moisture. The XRD curve of Figure 2c shows the results consistent with the SAED results of Figure 4. All of the diffraction peaks in Figure 2c confirm that the material is fcc Ni, which has a lattice constant: a = 3.540 , JCPDS card number 4-856, respectively (111), (200), (220), (311) and (222). No other impurities, such as the characteristic peaks of NiO and Ni(OH) ₂ , were detected. From the above experimental results of SAED and XRD, it is shown that the Ni phase having a good order of crystalline form characteristics can be prepared in an atmospheric environment.

The porous helical tetrahedral Ni, which is known to the inventors of the present invention, and its own standing block structure are prepared for the first time. It will be apparent that when the nanoporous PS template of the present invention is formed on the surface of a substrate, the improved electroless plating method of the present invention can prepare a large area of PS/Ni on the surface of the substrate. A spiral quaternary tetrahedral nano-mixed material, followed by removal of the PS main body, can be used to obtain a helical tetrahedral Ni having a large area of coverage on the surface of the substrate. Because the improved electroless plating method of the present invention does not need to provide an applied current as in general electrochemical deposition, the method of the present invention does not require first depositing a conductive layer on the surface of the substrate to form a layer of PS/Ni spiral thereon. A tetrahedral nano-mixed material or a spiral tetrahedral Ni. Furthermore, the improved electroless plating method of the present invention can utilize various known electroless plating formulations to prepare nanostructures of different metals.

Figure 1a shows a transmission electron microscope (TEM) photograph of a heat treated block copolymer PS-PLLA prepared in accordance with an embodiment of the present invention.

Figure 1b is a TEM photograph showing a non-stained [111] projection image of a PS/Ni spiral icosahedral nanomixture prepared in accordance with an embodiment of the present invention.

2a shows a 3D image reconstructed from a Ni nanostructure in a PS/Ni spiral icosahedral nanocomposite prepared in an embodiment of the present invention, which is projected from a series of different tilt angles to project 2D image reconstruction. get.

Figure 2b shows a field emission scanning electron microscopy (FESEM) image of a Ni nanostructure prepared in accordance with an embodiment of the present invention.

Figure 2c shows a wide-angle X-ray diffraction (XRD) curve of a porous helical tetrahedral Ni prepared in accordance with an embodiment of the present invention.

3 shows a low-magnification FESEM image of a Ni nanostructure prepared in an embodiment of the present invention, and a small image in the lower right corner is a photograph of the porous spiral twenty-tetrahedral Ni block.

Figure 4 shows a selected area electronic diffraction (SAED) pattern of a porous spiral twenty tetrahedron Ni prepared in accordance with an embodiment of the present invention.

Claims (27)

The utility model relates to a metal nanostructure which is above the public grade and can stand on its own, wherein the metal is nickel, gold, silver or copper, and the metal nanostructure which can stand on itself is a spiral quaternary nanostruture. , or a spiral nanostructure that is connected to each other. The metal nanostructure of claim 1, wherein the metal is nickel. The metal nanostructure of claim 1 or 2, wherein the nanostructure is a porous helical tetrahedral nanostructure. A metal nanostructure as claimed in claim 1 or 2 wherein the metal is crystalline. A metal nanostructure layer on a surface of a substrate having a coated area of up to 0.25 cm ² or more, wherein the metal is nickel, gold, silver or copper. The metal nanostructure layer of claim 5, wherein the metal is nickel. The metal nanostructure layer of claim 5 or 6, wherein the nanostructure is a porous spiral tetrahedral nanostructure. A metal nanostructure layer as claimed in claim 5 or 6, wherein the metal is in a crystalline state. The metal nanostructure layer of claim 5 or 6, wherein the nanostructure is a series of helical nanostructures having a periodic arrangement. The metal nanostructure layer of claim 5 or 6, wherein the nanostructure is a series of nanometer hexagonal closest packed cylindrical nanostructures with periodic arrangement. The metal nanostructure layer of claim 5, wherein the metal nanostructure layer has a thickness of from about 100 nm to about 200 nm. The metal nanostructure layer of claim 5, wherein the substrate is quartz, glass, polymer or semiconductor. The metal nanostructure layer of claim 5, wherein the surface is non-conductive. A device having a metal nanostructure, wherein the device is selected from the group consisting of a supercapacitor, a high energy density battery, a hydrogen storage container, an electromagnetic composite, a surface-enhanced Raman spectroscopy, an antimicrobial scaffold, and a filter , desalting device, heat sink, ultrahigh field electromagnets, and magnetic media; the metal is nickel, gold, silver or copper; the metal nanostructure is A a spiral hemitetrahedral nanostructure that can stand above the male grade, or a spiral nanostructure that is connected to each other, or B) a porous helix of 0.25 cm ² or more on the surface of a substrate A tetrahedral nanostructure, a series of periodically arranged helical nanostructures, or a series of periodically arranged hexagonal closest packed cylindrical nanostructures. A method for preparing a metal nanostructure, comprising the steps of: a) providing a nanoporous template; b) impregnating the nanoporous template with a solution containing palladium ions; c) removing the nanoporous from the solution a template, and washing the nanoporous template with a cleaning solution; d) immersing the washed nanoporous template in an electroless plating solution, so that the palladium ion in the nanopore of the nanoporous template is first reduced to a palladium atom, wherein the metal ion in the electroless plating solution is catalyzed by the palladium atom to be reduced to an elemental metal, and the nanopores of the nanoporous template are filled, wherein the metal is nickel, gold, silver or copper. The method of claim 15 further comprising the step of: e) removing the stepped d) nanoporous material of the filled elemental metal by using ultraviolet exposure, calcination, organic solvent, supercritical fluid or a combination thereof. The template leaves the metal in the nanopore and thus creates a metallic nanostructure. The method of claim 15, wherein the nanoporous template of step a) is a nanoporous template which is self-standing and has a porous helix tetrahedral nanochannel or a series of periodically arranged spirals. Nano channel. The method of claim 15, wherein the nanoporous template of step a) is a membrane layer formed on a surface of a substrate, and has a porous helix tetrahedral nanochannel, a series of periodic Arranged spiral nanochannels, or a series of periodically arranged hexagonal closest packed cylindrical nanochannels. The method of claim 17, wherein the nanoporous template of step a) has a porous helical tetrahedral nanochannel. The method of claim 18, wherein the nanoporous template of step a) has a porous helical tetrahedral nanochannel. The method of claim 15, wherein the palladium ion-containing solution in step b) has a palladium ion concentration of from 0.06 to 6.0 mg/ml. The method of claim 15, wherein the palladium ion-containing solution in step b) further comprises a surface tension modifier for enhancing wetting. The method of claim 22, wherein the surface tension modifier is a C1-C4 alcohol. The method of claim 22, wherein the palladium ion-containing solution of step b) further comprises a dissolution promoter which enhances dissolution of the palladium salt therein. The method of claim 24, wherein the dissolution promoter is an acid. The method of claim 14, wherein the electroless plating solution in step d) contains a reducing agent for reducing the palladium ions to palladium atoms. The method of claim 26, wherein the reducing agent is hydrazine, hydrazine hydroxide, formaldehyde, sodium borohydride, dimethylformamide, β-D-glucose, ethylene glycol, sodium citrate, ascorbic acid , dimethyl hydrazine, potassium hydrogen tartrate, methanol, ethanol, 1-propanol, 2-propanol, pyridine, poly(ethylene glycol), ginseng (trimethyldecyloxy) decane or hydrogen.