阅读说明：本技术 一种Cu-CNTs复合纳米导线及其制备方法和应用 (Cu-CNTs composite nano-wire and preparation method and application thereof ) 是由 宋旼 郭柏松 于 2021-09-14 设计创作，主要内容包括：本发明涉及一种Cu-CNTs复合纳米导线及其制备方法；属于电子元器件开发技术领域。所述Cu-CNTs复合纳米导线具有极大长径比,CNTs是芯部,CNTs表面被纳米Cu层均匀连续包覆。所述Cu-CNTs复合纳米导线的制备方法为：取商用CNTs经至少两次混合酸处理后,再用氯化亚锡溶液进行处理,接着再用银氨溶液进行处理,处理完成后再进行CNTs表面Cu层包覆。本发明所得产品可直接或间接应用于纳米尺度电路的构建。本发明材料结构设计合理,制备方法简单可控,所得产品性能优良,便于大规模工业化应用。(The invention relates to a Cu-CNTs composite nano-wire and a preparation method thereof; belongs to the technical field of electronic component development. The Cu-CNTs composite nano-wire has a great length-diameter ratio, CNTs are a core part, and the surface of the CNTs is uniformly and continuously coated by a nano Cu layer. The preparation method of the Cu-CNTs composite nano-wire comprises the following steps: and (2) treating commercial CNTs with mixed acid for at least two times, then treating with stannous chloride solution, then treating with silver ammonia solution, and then coating the surface Cu layer of the CNTs after the treatment is finished. The product obtained by the invention can be directly or indirectly applied to the construction of a nanoscale circuit. The material of the invention has reasonable structural design, simple and controllable preparation method, excellent performance of the obtained product and convenient large-scale industrial application.)

1. A Cu-CNTs composite nano wire is characterized in that: in the Cu-CNTs composite nano-wire, the surface of the CNTs is uniformly and continuously coated by a Cu layer.

2. The Cu-CNTs composite nanowire of claim 1, wherein: the thickness of a surface Cu layer in the Cu-CNTs composite nano wire is 20-40 nm; the diameter of a single Cu-CNTs composite nano wire is 30-100 nm; the aspect ratio is 200 or more.

3. A method for preparing Cu-CNTs composite nanowires as claimed in any of claims 1-2, comprising the following steps:

step one

Pretreating CNTs for at least 2 times by using mixed acid; washing the CNTs to be neutral after each pretreatment, drying, and then carrying out the next pretreatment; the mixed acid consists of concentrated sulfuric acid and concentrated nitric acid; obtaining the spare CNTs;

step two

Treating the spare CNTs obtained in the step one by using a stannous chloride solution, then treating by using a prepared mixed solution of silver nitrate and ammonia water, supplementing ultrasonic stirring in the treatment process, performing suction filtration after treatment at each stage is finished, washing to be neutral by using deionized water, and then performing suction filtration;

step three

Placing the CNTs treated in the second step into the mixed solution A, ultrasonically stirring for 4-6 minutes, then adjusting the pH value of the mixed solution A by means of sodium hydroxide, then placing the mixed solution A into a constant-temperature water bath box at 25-35 ℃, adding a certain amount of 3.4-3.7mol/L sodium hypophosphite solution into the mixed solution in a titration adding mode, simultaneously performing dropwise adding operation and mechanical stirring, performing suction filtration on the mixed solution after titration is completed, washing the mixed solution to be neutral by using deionized water, performing suction filtration, and drying;

the mixed solution A comprises the following components: 0.06-0.08mol/L sodium citrate, 0.05-0.07mol/L copper sulfate pentahydrate, 0.35-0.40mol/L boric acid and 0.004-0.006mol/L nickel sulfate.

4. The method for preparing Cu-CNTs composite nano-wire according to claim 3, characterized in that: in the first step, during the first acid treatment, the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid according to the volume ratio of 2.7: 1-3.2: 1; the concentration of the concentrated sulfuric acid is more than or equal to 98 percent, and the concentration of the concentrated nitric acid is more than or equal to 67 percent;

during the first acid treatment, the mass-volume ratio of the CNTs to the mixed acid solution is 1: 340-1: 360g/mL, the acid treatment time is 30-35min, and the acid treatment temperature is 78-82 ℃;

in the second and subsequent acid treatment, the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid according to the volume ratio of 1: 3-1: 4; the concentration of the concentrated sulfuric acid is more than or equal to 98 percent, and the concentration of the concentrated nitric acid is more than or equal to 67 percent; the mass-volume ratio of the CNTs to the acid mixed solution is 1: 450-1: 500g/mL, the acid treatment time is 2-5 h, and the acid treatment temperature is 88-92 ℃.

5. The method for preparing Cu-CNTs composite nano-wire according to claim 3, characterized in that: in the second step, the mass-volume ratio of the CNTs to the stannous chloride solution is 1: 1000-1: 1200g/mL, the concentration of the stannous chloride solution is 0.08-0.12mol/L, the treatment time is 1-3 h, and the treatment temperature is room temperature;

in the second step, the mass-volume ratio of the CNTs to the silver nitrate is 1: 1000-1: 1200g/mL, and the concentration of the silver nitrate solution is 3 multiplied by 10^-5The preparation process of the mixed solution of silver nitrate and ammonia water comprises the following steps: dropwise adding an ammonia water solution with the mass fraction of 25-28% into the silver nitrate solution in a titration adding mode, continuously stirring until the brown color is clear and transparent, and stopping dropwise adding, wherein the treatment time is 0.5-1 h, and the treatment temperature is room temperature.

6. The method for preparing Cu-CNTs composite nano-wire according to claim 3, characterized in that:

the mass-volume ratio of the CNTs to the mixed solution A in the third step is about 1: 900-1: 1000g/mL, and the volume ratio of the sodium hypophosphite solution to the mixed solution A after the PH value is adjusted is about 1: 4.5-1: 5.5;

in the third step, the pH value of the mixed solution A is adjusted to 10-13 by virtue of sodium hydroxide;

in the third step, the adding speed of titration addition of the sodium hypophosphite is controlled to be 1.5-4.0 mL/min, preferably 2.0-3.5 mL/min, and more preferably 2.5-3.5 mL/min.

7. Use of a Cu-CNTs composite nanowire according to any of claims 1-2, characterized by: the Cu-CNTs composite nano-wire is directly and/or indirectly applied to construction of a nanoscale circuit.

Technical Field

The invention relates to a Cu-CNTs composite nano-wire and a preparation method thereof; belongs to the technical field of electronic component development.

Background

Micro/nano devices play an extremely important role in the fields of military industry, aerospace, civil facilities and the like, and the development of high-performance micro/nano devices is a high-tech control point which is currently preempted in various countries around the world. For micro/nano devices, nanowires are one of the key components for realizing their functionality and ensuring their service reliability and safety, and are often required to have high conductivity, high mechanical properties, mechanical flexibility, and easy soldering. Cu is a common material for the conventional wire and the micron-scale wire at present due to the characteristics of high electric conductivity, high heat conductivity, low price, easy welding and the like. However, Cu has not been used in the field of nanowires because Cu nanowires having a diameter of several tens of nanometers cannot be prepared by the existing industrial preparation technology. In addition, it can be expected that the nanowire prepared only with pure Cu cannot have mechanical properties required for practical industrial applications due to the low strength of pure Cu. In order to improve the strength of pure Cu without reducing the electrical conductivity and the thermal conductivity of the pure Cu, a feasible method is to compound the pure Cu with a reinforcing phase with high strength, high electrical conductivity and high thermal conductivity to prepare the composite nano-wire.

As a hot spot carbon nanomaterial in recent years, Carbon Nanotubes (CNTs) have been fully demonstrated by theoretical simulation and experiment to have extremely excellent overall properties. The elasticity of the CNTs is higher than 1TPa, the tensile strength is up to 100GPa, and the thermal conductivity is up to 3000Wm^-1K^-1Conductivity up to 2X 10⁷Sm^-1The carrying capacity is as high as 10¹³Am^-2. Due to such excellent combination of properties of CNTs, it has been used as a reinforcing phase in bulk Cu-based composites. Research results show that after the CNTs are compounded, the mechanical property of the Cu-based composite material can be obviously improved, and meanwhile, the Cu-based composite material can have high conductivity equivalent to that of pure Cu. In addition, the CNTs are tubular structures, have extremely high length-diameter ratio and are very convenient to be used as a construction template for preparing the Cu nano-wires. If the CNTs and the Cu are compounded into the Cu-CNTs composite conductor, the compounding effect of the CNTs can be exerted, the advantage complementation of the Cu and the CNTs is realized, and the industrial application value and the service reliability of the composite nano conductor are greatly improved. Thereby completely breaking through the technical bottleneck that the existing wire preparation technology is difficult to prepare the nano wire.

It should be noted that the current combination of Cu and CNTs is only limited to the field of preparing bulk Cu-based composite materials. For example, patent CN107460458A discloses a method for electroless copper plating of multi-walled carbon nanotubes, which requires short cutting of CNTs, reduces the aspect ratio of CNTs, and has a complicated process and a long flow path in order to provide a suitable reinforcing phase for bulk Cu-based composites. Meanwhile, the technology cannot prepare the Cu-CNTs nano composite wire with a great length-diameter ratio. The nano composite wires of Cu-CNTs with extremely large length-diameter ratio and the surfaces of CNTs coated by continuous nano Cu layers have not been reported so far.

Disclosure of Invention

Aiming at the respective advantages and defects of the metal nanotubes and the CNTs and the preparation bottleneck of the current Cu nano conductor, the invention provides the preparation technology and the preparation method of the Cu-CNTs nano composite conductor which can be used for a nano-scale circuit, thereby meeting the requirements of semiconductor and chip industries on the nano conductor.

The invention creatively provides a new idea of preparing the Cu-CNTs nano composite wire with the extremely large length-diameter ratio by a self-assembly technology. Through the organic composition of Cu and CNTs, the high conductivity, high mechanical property and good mechanical flexibility required by a high-performance nano circuit on a nano wire can be perfectly realized, and the welding and production preparation are easy. The composite nano wire has a novel structure, has great potential application value in the fields of nano devices and chips, and is expected to play an important role in the development of the high-end communication field in China.

In the Cu-CNTs composite nano-wire, the surface of the CNTs is uniformly and continuously coated by a Cu layer.

According to the Cu-CNTs composite nano wire, the thickness of a copper layer in the Cu-CNTs composite nano wire is 20-40 nm; the diameter of a single Cu-CNTs composite nano wire is 30-100 nm; the aspect ratio is 200 or more.

The invention relates to a preparation method of a Cu-CNTs composite nano wire, which comprises the following steps:

step one

Pretreating CNTs for at least 2 times by using mixed acid; washing the CNTs to be neutral after each pretreatment, drying, and then carrying out the next pretreatment; the mixed acid consists of concentrated sulfuric acid and concentrated nitric acid; obtaining the spare CNTs;

step two

Treating the spare CNTs obtained in the step one by using a stannous chloride solution, then treating by using a prepared mixed solution of silver nitrate and ammonia water, supplementing ultrasonic stirring in the treatment process, performing suction filtration after treatment at each stage is finished, washing the CNTs to be neutral by using deionized water, and then performing suction filtration;

step three

Placing the CNTs treated in the second step into the mixed solution A, ultrasonically stirring for 4-6 minutes, then adjusting the pH value of the mixed solution A by means of sodium hydroxide, then placing the mixed solution A into a constant-temperature water bath tank at 25-35 ℃, adding a certain amount of 3.4-3.7mol/L sodium hypophosphite solution into the mixed solution in a titration adding mode, dropwise adding and mechanically stirring simultaneously, carrying out suction filtration on the mixed solution after titration is completed, washing the mixed solution to be neutral by using deionized water, and drying; when the sodium hypophosphite solution is dripped, the speed is controlled to be less than 4 mL/min;

the mixed solution A comprises the following components: 0.06-0.08mol/L sodium citrate (C)₆H₅Na₃O₇·2H₂O), 0.05-0.07mol/L copper sulfate pentahydrate (CuSO)₄·5H₂O), 0.350.40mol/L boric acid (H)₃BO₃) 0.004-0.006mol/L nickel sulfate (NiSO)₄·6H₂O)。

Preferably, in the first step of the preparation method of the Cu-CNTs composite nano wire, when acid treatment is carried out for the first time, mixed acid consists of concentrated sulfuric acid and concentrated nitric acid according to the volume ratio of 2.7: 1-3.2: 1; the concentration of the concentrated sulfuric acid is more than or equal to 98 percent, and the concentration of the concentrated nitric acid is more than or equal to 67 percent;

during the first acid treatment, the mass-volume ratio of the CNTs to the mixed acid solution is 1: 340-1: 360g/mL, the acid treatment time is 30-35min, and the acid treatment temperature is 78-82 ℃;

in the second and subsequent acid treatment, the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid according to the volume ratio of 1: 3-1: 4; the concentration of the concentrated sulfuric acid is more than or equal to 98 percent, and the concentration of the concentrated nitric acid is more than or equal to 67 percent; the mass-volume ratio of the CNTs to the acid mixed solution is 1: 450-1: 500g/mL, the acid treatment time is 2-5 h, and the acid treatment temperature is 88-92 ℃.

In the present invention, the first mixed acid treatment is mainly to remove impurities in the CNTs, and the second and subsequent acid treatments are mainly to graft enough functional groups on the surfaces of the CNTs. Thus, the amount of nitric acid used is increased in the second and subsequent acid treatments.

Preferably, in the second step of the preparation method of the Cu-CNTs composite nano wire, the mass-volume ratio of the CNTs to the stannous chloride solution is 1: 1000-1: 1200g/mL, the concentration of the stannous chloride solution is 0.08-0.12mol/L, the treatment time is 1-3 h, and the treatment temperature is room temperature.

In the second step, the mass-volume ratio of the CNTs to the silver nitrate is 1: 1000-1: 1200g/mL, and the concentration of the silver nitrate solution is 3 multiplied by 10^-5The preparation process of the mixed solution of silver nitrate and ammonia water comprises the following steps: dropwise adding an ammonia water solution with the mass fraction of 25-28% into the silver nitrate solution in a titration adding mode, continuously stirring until the brown color is clear and transparent, and stopping dropwise adding, wherein the treatment time is 0.5-1 h, and the treatment temperature is room temperature.

Preferably, in the preparation method of the Cu-CNTs composite nano wire, the mass-volume ratio of the CNTs to the mixed solution A in the step III is about 1: 900-1: 1000g/mL, and the volume ratio of the sodium hypophosphite solution to the mixed solution A after the PH value is adjusted is about 1: 4.5-1: 5.5.

In the third step, the pH value of the mixed solution A is adjusted to 10-13, preferably 12-13 by sodium hydroxide.

In the third step, the adding speed of titration addition of the sodium hypophosphite is controlled to be 1.5-4.0 mL/min, preferably 2.0-3.5 mL/min, and more preferably 2.5-3.5 mL/min.

As a further preferable scheme, the preparation method of the Cu-CNTs composite nano-wire comprises the following steps:

1) preparing 100mL of mixed acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 3:1, placing 0.3g of CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 30 minutes at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by the deionized water until the solution is neutral;

2) preparing 150mL of mixed acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 1:3, placing the pretreated CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 5 hours at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by the deionized water until the solution is neutral;

3) 50mL of deionized water was taken and the oxidized CNTs were placed therein and sonicated for 30 minutes. Preparing 350mL of 0.1mol/L stannous chloride solution, placing the CNTs subjected to ultrasonic treatment in the stannous chloride solution for ultrasonic treatment for 1 hour, standing for 30 minutes, then performing suction filtration, washing with deionized water, and then performing suction filtration;

4) taking 50mL of deionized water, placing CNTs treated by stannous chloride in the deionized water for ultrasonic treatment for 30 minutes, preparing 350mL of 3 multiplied by 10^-5Dropwise adding 25% ammonia water solution into a silver nitrate solution in a titration adding mode, continuously stirring until brown color becomes clear and transparent, stopping dropwise adding, placing CNTs subjected to ultrasonic treatment into the solution, performing ultrasonic treatment for 30 minutes, standing for 30 minutes, performing suction filtration, and washing with deionized water until the solution is neutral;

5) preparing 270mL of mixed solution A, placing CNTs (carbon nanotubes) treated by mixed solution of ammonia water and silver nitrate into the mixed solution A, ultrasonically stirring for 5 minutes, titrating, adding a sodium hydroxide solution into the mixed solution A until the PH value is 12, and ultrasonically stirring for 5 minutes; placing the mixed solution A with the pH value adjusted in a 30 ℃ constant temperature water bath tank, dropwise adding 54mL of 3.6mol/L sodium hypophosphite solution into the mixed solution at the speed of 3.5mL/min in a titration adding mode, simultaneously performing dropwise adding and mechanical stirring, magnetically stirring the mixed solution for 30 minutes, performing suction filtration, washing with deionized water to be neutral, and fully drying to obtain the Cu-CNTs composite nano conductor with the surface of CNTs uniformly coated by the Cu layer; the mixed solution A comprises the following components: 0.07mol/L sodium citrate, 0.06mol/L copper sulfate pentahydrate, 0.37mol/L boric acid and 0.005mol/L nickel sulfate.

As a further preferable scheme, the preparation method of the Cu-CNTs composite nano-wire comprises the following steps:

1) preparing 100mL of an acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 3.2:1, placing 0.3g of CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 30 minutes at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by deionized water until the solution is neutral;

2) preparing 150mL of mixed acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 1:3, placing the pretreated CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 4 hours at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by the deionized water until the solution is neutral;

3) 50mL of deionized water was taken and the oxidized CNTs were placed therein and sonicated for 30 minutes. Preparing 350mL of 0.1mol/L stannous chloride solution, placing the CNTs subjected to ultrasonic treatment in the stannous chloride solution for ultrasonic treatment for 2 hours, standing for 30 minutes, then performing suction filtration, washing with deionized water, and then performing suction filtration;

4) taking 50mL of deionized water, placing CNTs treated by stannous chloride in the deionized water for ultrasonic treatment for 30 minutes, preparing 350mL of 3 multiplied by 10^-5Dropwise adding 25% ammonia water solution into a silver nitrate solution in a titration adding mode, continuously stirring until brown color becomes clear and transparent, stopping dropwise adding, placing CNTs subjected to ultrasonic treatment into the solution, performing ultrasonic treatment for 30 minutes, standing for 30 minutes, performing suction filtration, and washing with deionized water until the solution is neutral;

5) preparing 270mL of mixed solution A, placing CNTs (carbon nanotubes) treated by mixed solution of ammonia water and silver nitrate into the mixed solution A, ultrasonically stirring for 5 minutes, titrating, adding a sodium hydroxide solution into the mixed solution A until the pH value is 12-13, and ultrasonically stirring for 5 minutes; placing the mixed solution A with the pH value adjusted in a 30 ℃ constant temperature water bath tank, dropwise adding 54mL of 3.6mol/L sodium hypophosphite solution into the mixed solution at the speed of 2.5mL/min in a titration adding mode, simultaneously performing dropwise adding and mechanical stirring, magnetically stirring the mixed solution for 30 minutes, performing suction filtration, washing with deionized water to be neutral, and fully drying to obtain the Cu-CNTs composite nano conductor with the surface of CNTs uniformly coated by the Cu layer; the mixed solution A comprises the following components: 0.07mol/L sodium citrate, 0.06mol/L copper sulfate pentahydrate, 0.37mol/L boric acid and 0.005mol/L nickel sulfate.

The Cu-CNTs composite nano-wire designed and prepared by the invention has better copper plating uniformity and continuity than the prior art, and the length of the product obtained by the invention is far longer than that of the product obtained by the prior art.

The Cu-CNTs nano composite wire with the large length-diameter ratio is prepared only through the synergistic effect of the working procedures and the working procedure parameters, and the Cu plating layer on the obtained Cu-CNTs nano composite wire is uniformly distributed.

The Cu-CNTs composite nano-wire designed and prepared by the invention is directly and/or indirectly applied to the construction of a nanoscale circuit.

Principles and advantages

Compared with the prior art which can not prepare the Cu nano-wire, the method for preparing the Cu-CNTs composite nano-wire by taking the CNTs as the construction template has the following advantages:

1) the CNTs have excellent comprehensive performance, the performance of the Cu nano-wire can be obviously improved by exploring the composite effect of the CNTs, and the performance and the service reliability of a nano device can be effectively improved.

2) The Cu-CNTs composite nano-wire is prepared by adopting a self-assembly process, the process is simple and easy to operate, the flow parameters are easy to control, the requirements of the preparation process on equipment and fields are lower, and the production cost is lower.

3) The prepared Cu-CNTs composite nano-wire can be directly applied to the construction of a nanoscale circuit and has extremely wide application prospect.

Drawings

FIG. 1 is a TEM image of the Cu-CNTs composite nanowire obtained in comparative example 1;

FIG. 2 is a TEM image of the Cu-CNTs composite nanowire obtained in comparative example 3;

FIG. 3 is a TEM image of the Cu-CNTs composite nanowire obtained in example 1;

FIG. 4 is a high power TEM image of Cu-CNTs nano composite wire obtained in example 2;

FIG. 5 is the XRD pattern of the Cu-CNTs nano-composite wire obtained in example 2.

As can be seen from the attached FIG. 1, only a small amount of nano Cu particles are formed on the surfaces of the CNTs, no continuous Cu layer is formed, and the quality of the composite wire is poor.

As can be seen from fig. 2, compared to fig. 1, in the CNTs table, a larger number of nano-Cu particles are formed, but a continuous Cu layer is not formed yet, and the quality of the composite wire is poor.

It can be seen from fig. 3 that the multi-walled carbon nanotubes are completely uniformly coated with copper, and the thickness of the coated copper layer is of the order of nanometers.

From fig. 4, it can be seen that the multi-walled carbon nanotube is completely and uniformly coated with copper, the surface is smooth and continuous, and the thickness of the coated copper layer is in the nanometer level.

It can be seen from fig. 5 that the composite nanowire has continuous and stable components, and the effect of the copper-coated multi-walled carbon nanotube is excellent.

The specific implementation mode is as follows:

the components of the mixed solution a used in examples 1 to 2 of the present invention and comparative examples 1 to 3 were: 0.07mol/L sodium citrate (C)₆H₅Na₃O₇·2H₂O), 0.06mol/L copper sulfate pentahydrate (CuSO)₄·5H₂O), 0.37mol/L boric acid (H)₃BO₃) 0.005mol/L Nickel sulfate (NiSO)₄·6H₂O)。

The concentration of concentrated sulfuric acid used in the examples of the present invention and the comparative examples was 98%, and the concentration of concentrated nitric acid used was 67%.

Comparative example 1

1) Preparing 100mL of an acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 3.2:1, placing 0.3g of CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 30 minutes at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by deionized water until the solution is neutral;

2) 50mL of deionized water was taken and the oxidized CNTs were placed therein and sonicated for 30 minutes. Preparing 350mL of 0.1mol/L stannous chloride solution, placing the CNTs subjected to ultrasonic treatment in the stannous chloride solution for ultrasonic treatment for 2 hours, standing for 30 minutes, then performing suction filtration, washing with deionized water, and then performing suction filtration;

3) taking 50mL of deionized water, placing CNTs treated by stannous chloride in the deionized water for ultrasonic treatment for 30 minutes, preparing 350mL of 3 multiplied by 10^-5Dripping the mass of the silver nitrate solution into the silver nitrate solution by adopting a titration adding modeContinuously stirring ammonia water solution with the fraction of 25% until the brown color becomes clear and transparent, stopping dripping, putting the multi-walled carbon nano-tube subjected to ultrasonic treatment into the solution, performing ultrasonic treatment for 30 minutes, standing for 30 minutes, performing suction filtration, and washing with deionized water until the solution is neutral;

4) preparing 270mL of mixed solution A, placing CNTs treated by mixed solution of ammonia water and silver nitrate into the mixed solution A, ultrasonically stirring for 5 minutes, titrating, adding a sodium hydroxide solution into the mixed solution A until the pH value is 10, and ultrasonically stirring for 5 minutes. And (3) placing the mixed solution A with the pH value adjusted in a 30-DEG C constant-temperature water bath tank, dropwise adding 54mL of 3.6mol/L sodium hypophosphite solution at the speed of 2.5mL/min in a titration adding mode (dropwise adding and mechanical stirring are carried out simultaneously), magnetically stirring the mixed solution for 30 minutes, then carrying out suction filtration, washing with deionized water to be neutral, and fully drying. Transmission electron microscope characterization shows that only a small number of nano Cu particles are formed on the partial surface of the CNTs (as shown in figure 1), and the quality of the Cu-CNTs composite nano wire is poor.

Comparative example 2

1) Preparing 100mL of an acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 3.2:1, placing 0.3g of CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 30 minutes at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by deionized water until the solution is neutral;

2) preparing 150mL of mixed acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 1:3, placing the pretreated CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 3 hours at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by the deionized water until the solution is neutral;

3) 50mL of deionized water was taken and the oxidized CNTs were placed therein and sonicated for 30 minutes. Preparing 350mL of 0.1mol/L stannous chloride solution, placing the CNTs subjected to ultrasonic treatment in the stannous chloride solution for ultrasonic treatment for 2 hours, standing for 30 minutes, then performing suction filtration, washing with deionized water, and then performing suction filtration;

4) taking 50mL of deionized water, placing CNTs treated by stannous chloride in the deionized water for ultrasonic treatment for 30 minutes, preparing 350mL of 3 multiplied by 10^-5A silver nitrate solution with the concentration of mol/L,dropwise adding an ammonia water solution with the mass fraction of 25% into a silver nitrate solution in a titration adding mode, continuously stirring until the brown color is clear and transparent, stopping dropwise adding, placing the multiwalled carbon nanotube subjected to ultrasonic treatment into the solution, performing ultrasonic treatment for 30 minutes, standing for 30 minutes, performing suction filtration, and washing with deionized water until the multiwalled carbon nanotube is neutral;

5) preparing 270mL of mixed solution A, placing CNTs treated by mixed solution of ammonia water and silver nitrate into the mixed solution A, ultrasonically stirring for 5 minutes, titrating, adding a sodium hydroxide solution into the mixed solution A until the pH value is 10, and ultrasonically stirring for 5 minutes. And (3) placing the mixed solution A with the pH value adjusted in a 30-DEG C constant-temperature water bath tank, dropwise adding 54mL of 3.6mol/L sodium hypophosphite solution at the speed of 2.5mL/min in a titration adding mode (dropwise adding and mechanical stirring are carried out simultaneously), magnetically stirring the mixed solution for 30 minutes, then carrying out suction filtration, washing with deionized water to be neutral, and fully drying. Transmission electron microscope characterization shows that the surface of the CNTs is not completely coated by the Cu layer, and the quality of the Cu-CNTs composite nano-wire is poor.

Comparative example 3

1) Preparing 100mL of an acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 2.7:1, placing 0.3g of CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 30 minutes at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by deionized water until the solution is neutral;

2) preparing 150mL of mixed acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 1:3, placing the pretreated CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 2 hours at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by the deionized water until the solution is neutral;

3) 50mL of deionized water was taken and the oxidized CNTs were placed therein and sonicated for 30 minutes. Preparing 350mL of 0.1mol/L stannous chloride solution, placing the CNTs subjected to ultrasonic treatment in the stannous chloride solution for ultrasonic treatment for 2 hours, standing for 30 minutes, then performing suction filtration, washing with deionized water, and then performing suction filtration;

4) taking 50mL of deionized water, placing CNTs treated by stannous chloride in the deionized water for ultrasonic treatment for 30 minutes, preparing 350mL of 3 multiplied by 10^-5mol/L ofDropwise adding an ammonia water solution with the mass fraction of 25% into a silver nitrate solution in a titration adding mode, continuously stirring until the brown color becomes clear and transparent, stopping dropwise adding, placing the multiwalled carbon nanotube subjected to ultrasonic treatment into the solution, performing ultrasonic treatment for 30 minutes, standing for 30 minutes, performing suction filtration, and washing with deionized water until the multiwalled carbon nanotube is neutral;

5) preparing 270mL of mixed solution A, placing CNTs treated by mixed solution of ammonia water and silver nitrate into the mixed solution A, ultrasonically stirring for 5 minutes, titrating, adding a sodium hydroxide solution into the mixed solution A until the pH value is 13, and ultrasonically stirring for 5 minutes. And (3) placing the mixed solution A with the pH value adjusted in a 30-DEG C constant-temperature water bath tank, dropwise adding 54mL of 3.6mol/L sodium hypophosphite solution at the speed of 1.5mL/min in a titration adding mode (dropwise adding and mechanical stirring are carried out simultaneously), magnetically stirring the mixed solution for 30 minutes, carrying out suction filtration, washing with deionized water to be neutral, and fully drying. Transmission electron microscope characterization shows that the number of nano Cu particles formed on the partial surface of the CNTs is significantly larger than that of the nano Cu particles formed in the comparative example 1, but a Cu-CNTs composite nano wire taking Cu-coated CNTs as a structural characteristic is not formed (as shown in FIG. 2).

Comparative example 4

1) Preparing 100mL of an acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 2.7:1, placing 0.3g of CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 30 minutes at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by deionized water until the solution is neutral;

2) preparing 150mL of mixed acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 1:3, placing the pretreated CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 3 hours at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by the deionized water until the solution is neutral;

3) 50mL of deionized water was taken and the oxidized CNTs were placed therein and sonicated for 30 minutes. Preparing 350mL of 0.1mol/L stannous chloride solution, placing the CNTs subjected to ultrasonic treatment in the stannous chloride solution for ultrasonic treatment for 2 hours, standing for 30 minutes, then performing suction filtration, washing with deionized water, and then performing suction filtration;

4) taking 50mL of deionized water, and then taking the deionized water,the CNTs treated by stannous chloride are placed in the mixture for ultrasonic treatment for 30 minutes, and 350mL, 3X 10 are prepared^-5Dropwise adding 25% ammonia water solution into the silver nitrate solution in a titration adding mode, continuously stirring until the brown color becomes clear and transparent, stopping dropwise adding, placing the multiwalled carbon nanotube subjected to ultrasonic treatment into the solution, performing ultrasonic treatment for 30 minutes, standing for 60 minutes, performing suction filtration, and washing with deionized water until the multiwalled carbon nanotube is neutral;

5) preparing 270mL of mixed solution A, placing CNTs treated by mixed solution of ammonia water and silver nitrate into the mixed solution A, ultrasonically stirring for 5 minutes, titrating, adding a sodium hydroxide solution into the mixed solution A until the pH value is 13, and ultrasonically stirring for 5 minutes. And (3) placing the mixed solution A with the pH value adjusted in a 30-DEG C constant-temperature water bath tank, dropwise adding 54mL of 3.6mol/L sodium hypophosphite solution at the speed of 4.5mL/min in a titration adding mode (dropwise adding and mechanical stirring are carried out simultaneously), magnetically stirring the mixed solution for 30 minutes, then carrying out suction filtration, washing with deionized water to be neutral, and fully drying. Transmission electron microscope characterization shows that only coarse Cu particles are formed on the surface of the CNTs part, the Cu particles are discontinuous, and the Cu-CNTs composite nano-wire is not formed.

Example 1

1) Preparing 100mL of mixed acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 3:1, placing 0.3g of CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 30 minutes at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by the deionized water until the solution is neutral;

2) preparing 150mL of mixed acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 1:3, placing the pretreated CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 5 hours at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by the deionized water until the solution is neutral;

3) 50mL of deionized water was taken and the oxidized CNTs were placed therein and sonicated for 30 minutes. Preparing 350mL of 0.1mol/L stannous chloride solution, placing the CNTs subjected to ultrasonic treatment in the stannous chloride solution for ultrasonic treatment for 1 hour, standing for 30 minutes, then performing suction filtration, washing with deionized water, and then performing suction filtration; (ii) a

4) Taking 50mL of deionized water, placing CNTs treated by stannous chloride in the deionized water for ultrasonic treatment for 30 minutes, preparing 350mL of 3 multiplied by 10^-5Dropwise adding 25% ammonia water solution into the silver nitrate solution in a titration adding mode, continuously stirring until the brown color becomes clear and transparent, stopping dropwise adding, placing the multiwalled carbon nanotube subjected to ultrasonic treatment into the solution, performing ultrasonic treatment for 30 minutes, standing for 30 minutes, performing suction filtration, and washing with deionized water until the multiwalled carbon nanotube is neutral;

5) preparing 270mL of mixed solution A, placing CNTs treated by mixed solution of ammonia water and silver nitrate into the mixed solution A, ultrasonically stirring for 5 minutes, titrating, adding a sodium hydroxide solution into the mixed solution A until the pH value is 12, and ultrasonically stirring for 5 minutes. And (3) placing the mixed solution A with the pH value adjusted in a 30-DEG C constant-temperature water bath box, dropwise adding 54mL of 3.6mol/L sodium hypophosphite solution into the mixed solution at the speed of 3.5mL/min in a titration adding mode (dropwise adding and mechanical stirring are carried out simultaneously), magnetically stirring the mixed solution for 30 minutes, carrying out suction filtration, washing with deionized water to be neutral, and fully drying. Transmission electron microscope characterization shows that the surface of the CNTs is uniformly coated by the Cu layer to form the Cu-CNTs composite nano-wire. The thickness of a continuous copper layer in the obtained Cu-CNTs composite nano wire is 20-40 nm; the diameter of a single Cu-CNTs composite nano wire is 30-50 nm; the aspect ratio is 200 or more.

The obtained Cu-CNTs composite nano-wire is directly and/or indirectly applied to the construction of a nanoscale circuit. Nanoscale circuits are formed, such as by soldering.

Example 2

1) Preparing 100mL of an acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 3.2:1, placing 0.3g of CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 30 minutes at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by deionized water until the solution is neutral;

2) preparing 150mL of mixed acid solution with the ratio of concentrated sulfuric acid to concentrated nitric acid being 1:3, placing the pretreated CNTs into the prepared mixed acid solution, performing ultrasonic treatment for 5 minutes, performing magnetic stirring for 4 hours at 90 ℃, then diluting by 3 times of deionized water, performing suction filtration, and washing by the deionized water until the solution is neutral;

3) 50mL of deionized water was taken and the oxidized CNTs were placed therein and sonicated for 30 minutes. Preparing 350mL of 0.1mol/L stannous chloride solution, placing the CNTs subjected to ultrasonic treatment in the stannous chloride solution for ultrasonic treatment for 2 hours, standing for 30 minutes, then performing suction filtration, washing with deionized water, and then performing suction filtration;

4) taking 50mL of deionized water, placing CNTs treated by stannous chloride in the deionized water for ultrasonic treatment for 30 minutes, preparing 350mL of 3 multiplied by 10^-5Dropwise adding 25% ammonia water solution into the silver nitrate solution in a titration adding mode, continuously stirring until the brown color becomes clear and transparent, stopping dropwise adding, placing the multiwalled carbon nanotube subjected to ultrasonic treatment into the solution, performing ultrasonic treatment for 30 minutes, standing for 30 minutes, performing suction filtration, and washing with deionized water until the multiwalled carbon nanotube is neutral;

5) preparing 270mL of mixed solution A, placing CNTs treated by mixed solution of ammonia water and silver nitrate into the mixed solution A, ultrasonically stirring for 5 minutes, titrating, adding a sodium hydroxide solution into the mixed solution A until the pH value is 12-13, and ultrasonically stirring for 5 minutes. And (3) placing the mixed solution A with the pH value adjusted in a 30-DEG C constant-temperature water bath box, dropwise adding 54mL of 3.6mol/L sodium hypophosphite solution into the mixed solution at the speed of 2.5mL/min in a titration adding mode (dropwise adding and mechanical stirring are carried out simultaneously), magnetically stirring the mixed solution for 30 minutes, carrying out suction filtration, washing with deionized water to be neutral, and fully drying. Transmission electron microscope characterization shows that the surface of the CNTs is uniformly coated by the Cu layer to form the Cu-CNTs composite nano-wire. The thickness of a copper layer in the obtained Cu-CNTs composite nano wire is 20-40 nm; the diameter of a single Cu-CNTs composite nano wire is 30-50 nm; the aspect ratio is 200 or more.

The obtained Cu-CNTs composite nano-wire is directly applied to the construction of a nanoscale circuit.

The above comparative examples and examples are only some specific examples for illustrating the present invention, and the present invention is not limited to the above comparative examples and examples. On the basis of the embodiment of the invention, scientific research and engineering technicians can make changes and adjustments of different forms such as reagent components, process parameters, procedures and the like, and the changes caused by the changes belong to the scope of authority protection of the invention.