A multilayer carbon nanotube array / polydimethylsiloxane composite material with both elasticity and high thermal conductivity

Abstract

The present invention relates to a multilayer elastic carbon nanotube array composite material, and the preparation method thereof is as follows: firstly, a quartz sheet is placed in a beaker containing ethanol and ultrasonicated for 30 minutes, then taken out, then rinsed with flowing ethanol and deionized water, dried and set aside, and then a carbon nanotube array is grown on the surface of the quartz sheet by chemical vapor deposition, and the orientation direction of the obtained carbon nanotube array is perpendicular to the plane direction of the metal sheet, and is evenly and densely distributed on the surface of the quartz sheet. The multilayer carbon nanotube array can be obtained by controlling the number of growths, and the carbon nanotube array obtained by subsequent multiple growths is neatly and evenly arranged; the growth height of the array can also be controlled by controlling the growth time. Finally, the multilayer carbon nanotube array is compounded with polydimethylsiloxane, and the obtained multilayer carbon nanotube array is tightly connected at the interface of multiple growth processes and forms a compressible rebound space, so that the composite material has excellent compression resilience and thermal conductivity.

Description

Technical Field

[0001] The invention relates to a multilayer carbon nanotube array / polydimethylsiloxane composite material having both elasticity and high thermal conductivity, belonging to the field of thermal conductive composite materials. Background Art

[0002] In recent years, science and technology have developed rapidly, and the production of electronic products has begun to develop in the direction of high frequency and integration. Along with this, the heat generation problem of highly integrated micro-electronic devices has come along. Therefore, thermal management technology has become a key issue restricting its development. The emergence of high performance and high integration of electronic equipment has led to a sharp increase in the heat generation per unit area of ​​electronic components. If the generated heat is not directed out in time, a large amount of heat retention and accumulation will cause damage to the electronic components, thereby greatly affecting the working performance and life of the electronic equipment. At the same time, the vibration extrusion accompanied by mechanical and electronic equipment during operation has also put forward new requirements for materials. Traditional thermal conductive materials have high density, large thermal expansion coefficient, and no elasticity. They are easily damaged and failed during the reciprocating extrusion process, and can no longer meet the needs of future development. Carbon nanotube arrays have ultra-high directional thermal conductivity, low density, chemical corrosion resistance, and low thermal expansion. They are the most promising thermal conductive materials in the future. However, the compression resilience and durability of carbon nanotube arrays are relatively poor. Therefore, how to prepare composite materials with both compression resilience and high thermal conductivity has become a research hotspot in the field of thermal conductivity at this stage. Summary of the invention

[0003] The object of the present invention is to provide a multilayer carbon nanotube array / polydimethylsiloxane composite material having both elasticity and high thermal conductivity, wherein the carbon nanotube arrays are tightly connected and have high directional thermal conductivity and compression rebound performance.

[0004] The present invention adopts the following technical solution:

[0005] The present invention relates to a method for preparing a multilayer carbon nanotube array / polydimethylsiloxane composite material, and the steps are as follows:

[0006] 1) Surface treatment of quartz sheet: The quartz sheet was immersed in ethanol for ultrasonic treatment to remove impurities remaining on the surface. Then, the surface of the sheet was rinsed with flowing ethanol and deionized water respectively, and dried for use.

[0007] 2) Growth of carbon nanotube array: Ferrocene is dissolved in xylene to prepare a catalyst carbon source solution with a concentration of 0.02-0.06 g / ml. The metal sheet obtained in step 1) is placed in a tube furnace and heated to 860°C. After reaching the set temperature, the catalyst carbon source solution is injected into the tube furnace through a micro-injection pump and kept warm for 10-60 minutes to grow the carbon nanotube array and obtain a quartz sheet with a single-layer carbon nanotube array on the surface.

[0008] 3) Secondary growth and multiple growth of carbon nanotube arrays: When the temperature of the tube furnace in step 2) drops below 700°C, restart the tube furnace heating device, and the subsequent steps are as in step 2). Finally, a quartz sheet with two or more layers of carbon nanotube arrays on the surface is obtained.

[0009] 4) Composite of multilayer carbon nanotube array and polydimethylsiloxane: The multilayer carbon nanotube array obtained in step 3) was etched and peeled off with hydrofluoric acid, and then freeze-dried after being immersed in water for 24 hours. It was then vacuum-impregnated in polydimethylsiloxane for multiple times and heated to obtain a multilayer carbon nanotube array / polydimethylsiloxane composite material.

[0010] Preferably, in step 2), the argon gas flow rate is 500-1000 sccm, and the hydrogen gas flow rate is 30-80 sccm.

[0011] Preferably, the heating rate in step 2) is 5 to 15° C. / min.

[0012] Preferably, the heating rate in step 2) is 5 to 15° C. / min.

[0013] Preferably, in step 2), a medical syringe is used to inject the catalyst precursor solution into the tube furnace at a uniform rate of 10 to 30 ml / h under the action of a microinjection pump.

[0014] Preferably, the heating temperature in step 4) is 40-60°C.

[0015] The present invention in-situ grows a carbon nanotube array on the surface of a quartz sheet by chemical vapor deposition, and the obtained carbon nanotube has a diameter of 20 to 140 nm and a length of 100 to 300 μm. The orientation direction of the carbon nanotube is perpendicular to the plane direction of the quartz sheet and is evenly and densely distributed on the surface of the metal sheet. The multilayer carbon nanotube array is tightly connected at the interface of multiple growth processes and forms a compressible and resilient space, so that the composite material has both high thermal conductivity and compression resilience. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the multilayer carbon nanotube array / polydimethylsiloxane composite material of the present invention;

[0017] Figure 2 is a scanning electron microscope image of the multilayer carbon nanotube array of the present invention;

[0018] Figure 3 This is an electron microscope image of the multilayer carbon nanotube array / polydimethylsiloxane composite material of the present invention;

[0019] Figure 4 is a compression-rebound curve diagram of the multilayer carbon nanotube array / polydimethylsiloxane composite material of the present invention; DETAILED DESCRIPTION

[0020] Three embodiments of the present invention are provided below to further illustrate the present invention, but not to limit the scope of the present invention.

[0021] Example 1

[0022] 1) Surface treatment of quartz sheet: The quartz sheet was immersed in ethanol for ultrasonic treatment to remove impurities remaining on the surface. Then, the surface of the sheet was rinsed with flowing ethanol and deionized water respectively, and dried for use.

[0023] 2) Growth of carbon nanotube array: Ferrocene was dissolved in xylene to prepare a catalyst carbon source solution with a concentration of 0.06 g / ml. The metal sheet obtained in step 1) was placed in a tube furnace and heated to 860°C. After reaching the set temperature, the catalyst carbon source solution was injected into the tube furnace through a micro-injection pump and kept warm for 10 minutes to grow the carbon nanotube array and obtain a quartz sheet with a single-layer carbon nanotube array on the surface.

[0024] 3) Secondary growth and multiple growth of carbon nanotube arrays: When the temperature of the tube furnace in step 2) drops below 700°C, restart the tube furnace heating device, and the subsequent steps are as in step 2). Finally, a quartz sheet with two or more layers of carbon nanotube arrays on the surface is obtained.

[0025] 4) Composite of multilayer carbon nanotube array and polydimethylsiloxane: The multilayer carbon nanotube array obtained in step 3) was etched and peeled off with hydrofluoric acid, and then freeze-dried after being immersed in water for 24 hours. It was then vacuum-impregnated in polydimethylsiloxane for multiple times and heated and cured at 40°C to obtain a multilayer carbon nanotube array / polydimethylsiloxane composite material.

[0026] The length of a single-layer carbon nanotube measured by scanning electron microscopy is 100 μm. To illustrate the heat dissipation effect of the invented material, the obtained sheet was placed on a 100°C hot plate and a commercially available polyimide film was attached at the same time. The infrared thermal imager was used to detect that the surface temperature of the composite material was 3.1°C higher than that of the blank copper sheet, indicating that the sheet obtained by the invention has better heat dissipation.

[0027] Example 2

[0028] 1) Surface treatment of quartz sheet: The quartz sheet was immersed in ethanol for ultrasonic treatment to remove impurities remaining on the surface. Then, the surface of the sheet was rinsed with flowing ethanol and deionized water respectively, and dried for use.

[0029] 2) Growth of carbon nanotube array: Ferrocene was dissolved in xylene to prepare a catalyst carbon source solution with a concentration of 0.06 g / ml. The metal sheet obtained in step 1) was placed in a tube furnace and heated to 860°C. After reaching the set temperature, the catalyst carbon source solution was injected into the tube furnace through a micro-injection pump and kept warm for 30 minutes to grow the carbon nanotube array, and a quartz sheet with a single-layer carbon nanotube array on the surface was obtained.

[0030] 3) Secondary growth and multiple growth of carbon nanotube arrays: When the temperature of the tube furnace in step 2) drops below 700°C, restart the tube furnace heating device, and the subsequent steps are as in step 2). Finally, a quartz sheet with two or more layers of carbon nanotube arrays on the surface is obtained.

[0031] 4) Composite of multilayer carbon nanotube array and polydimethylsiloxane: The multilayer carbon nanotube array obtained in step 3) was etched and peeled off with hydrofluoric acid, and then freeze-dried after being immersed in water for 24 hours. It was then vacuum-impregnated in polydimethylsiloxane for multiple times and heated at 50°C for curing to obtain a multilayer carbon nanotube array / polydimethylsiloxane composite material.

[0032] The length of a single-layer carbon nanotube measured by scanning electron microscopy is 180 μm. To illustrate the heat dissipation effect of the invented material, the obtained sheet was placed on a 100°C hot plate and a commercially available polyimide film was attached at the same time. Using an infrared thermal imager, it was found that the surface temperature of the composite material was 4.7°C higher than that of the blank copper sheet, indicating that the sheet obtained by the invention has better heat dissipation.

[0033] Example 3

[0034] 1) Surface treatment of quartz sheet: The quartz sheet was immersed in ethanol for ultrasonic treatment to remove impurities remaining on the surface. Then, the surface of the sheet was rinsed with flowing ethanol and deionized water respectively, and dried for use.

[0035] 2) Growth of carbon nanotube array: Ferrocene was dissolved in xylene to prepare a catalyst carbon source solution with a concentration of 0.06 g / ml. The metal sheet obtained in step 1) was placed in a tube furnace and heated to 860°C. After reaching the set temperature, the catalyst carbon source solution was injected into the tube furnace through a micro-injection pump and kept warm for 60 minutes to grow the carbon nanotube array and obtain a quartz sheet with a single-layer carbon nanotube array on the surface.

[0036] 3) Secondary growth and multiple growth of carbon nanotube arrays: When the temperature of the tube furnace in step 2) drops below 700°C, restart the tube furnace heating device, and the subsequent steps are as in step 2). Finally, a quartz sheet with two or more layers of carbon nanotube arrays on the surface is obtained.

[0037] 4) Composite of multilayer carbon nanotube array and polydimethylsiloxane: The multilayer carbon nanotube array obtained in step 3) was etched and peeled off with hydrofluoric acid, and then freeze-dried after being immersed in water for 24 hours. It was then vacuum-impregnated in polydimethylsiloxane for multiple times and heated at 60°C for curing to obtain a multilayer carbon nanotube array / polydimethylsiloxane composite material.

[0038] The length of a single-layer carbon nanotube measured by scanning electron microscopy was 270 μm. To illustrate the heat dissipation effect of the invented material, the obtained sheet was placed on a 100°C hot plate and a commercially available polyimide film was attached at the same time. Using an infrared thermal imager, it was found that the surface temperature of the composite material was 5.9°C higher than that of the blank copper sheet, indicating that the sheet obtained by the invention has better heat dissipation.

Claims

1. A method for preparing a multilayer carbon nanotube array / polydimethylsiloxane composite material having both elasticity and high thermal conductivity, characterized in that: The preparation steps are as follows: 1) Surface treatment of quartz sheet: immerse the quartz sheet in ethanol for ultrasonic treatment to remove impurities remaining on the surface, then rinse the surface of the sheet with flowing ethanol and deionized water respectively, and dry it for later use; 2) Growth of carbon nanotube arrays: dissolving ferrocene in xylene to prepare a catalyst carbon source solution with a concentration of 0.02 to 0.06 g / ml; placing the quartz sheet obtained in step 1) in a tube furnace, heating it to 860° C., and after reaching the set temperature, injecting the catalyst carbon source solution into the tube furnace through a microinjection pump, and keeping the temperature for 10 to 60 minutes to grow the carbon nanotube array, and obtaining a quartz sheet with a single-layer carbon nanotube array on the surface; 3) Secondary growth and multiple growth of carbon nanotube arrays: After the temperature of the tube furnace in step 2) drops below 700°C, restart the tube furnace heating device, and the subsequent steps are the same as step 2), and finally obtain a quartz sheet with two or more layers of carbon nanotube arrays on the surface; 4) Composite of multilayer carbon nanotube array and polydimethylsiloxane: The multilayer carbon nanotube array obtained in step 3) was etched and peeled off with hydrofluoric acid, and then freeze-dried after being immersed in water for 24 hours. It was then vacuum-impregnated in polydimethylsiloxane for multiple times and heated to obtain a multilayer carbon nanotube array / polydimethylsiloxane composite material.

2. The method according to claim 1, characterized in that: Step 2) heating rate 5-15°C / min.

3. The method according to claim 1, characterized in that: Step 3) heating rate 5-15°C / min.

4. The method according to claim 1, wherein the carbon nanotubes The orientation direction is perpendicular to the plane direction of the quartz sheet, and the carbon nanotubes are evenly and densely distributed on the surface of the quartz sheet. The multi-layer carbon nanotube arrays are tightly connected to form a compressible and resilient space.

5. The method according to claim 1, characterized in that: The diameter of each layer of carbon nanotubes is between 20 and 140 nm, and the length is 100-300 μm.

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