A method for manufacturing nanoscale channel fluidic devices based on carbon nanotube templates

Abstract

The present invention relates to a method for manufacturing a nano-scale channel fluidic device based on a carbon nanotube template, comprising three steps of manufacturing a PDMS micron channel substrate, manufacturing a carbon nanotube mold and manufacturing a PDMS nano-channel fluidic device. Carbon nanotubes are used to form carbon nanotubes with uniform distribution and consistent directions under the action of an alternating electric field and ultrasonic vibration, thereby providing a mold for the manufacture of nano-channels. Compared with the existing nano-channel manufacturing method, the present invention has the advantages of simple manufacturing process, convenient operation, lower cost, no need to rely on clean room equipment, and provides a reference for the preparation of 10-nanometer-scale channels, which is conducive to the application and promotion of nano-scale channels.

Description

Technical Field

[0001] The present invention relates to a method for preparing a nanoscale channel fluidic device, and in particular to a method for manufacturing a nanoscale channel fluidic device based on an ordered arrangement of carbon nanotube templates. Background Art

[0002] Two-dimensional nanochannels refer to closed channels with a width and depth of nanometers. Due to the unique properties of two-dimensional nanochannels, such as double electric dipole superposition, extremely high surface-to-volume ratio and quantum tunneling effect, nanochannels can achieve functions that micrometer and macro channels cannot achieve. For example, when the channel size is reduced to the nanoscale, the double electric dipole in the channel is superimposed. Usually, a large amount of positive charges accumulate in this layer, which makes it difficult for negative charges to pass through the nanochannel under the electric field. This makes the nanochannel have charge screening characteristics and can be used for protein screening and enrichment; the extremely high surface-to-volume ratio makes the nanochannel have extremely fast heating and heat dissipation characteristics, and the heating and cooling of samples in the channel can be balanced at the millisecond level, making the two-dimensional nanochannel have potential applications in catalysis and confined chemical reactions; the quantum tunneling effect of the two-dimensional nanochannel enables the particles to have the ability to penetrate the potential barrier. This characteristic makes the two-dimensional nanochannel have important application value in high-resolution sensors, especially wearable tactile sensors.

[0003] With the improvement of processing technology, fluidic devices with hundreds of nanometer channels can now be manufactured using traditional processing technologies, such as wet etching, electrospark machining, and even 3D printing methods. Compared with the large-sized nanochannels, fluidic devices with channels below 100 nanometers have a wider application prospect, especially fluidic devices with 10 nanometer channels, which have better chemical and physical properties and are ideal structures for supercapacitors, full-spectrum solar cells, and ultra-high electron mobility transistors. However, at present, 10-nanometer channels can only be manufactured using methods such as femtosecond laser, deep reactive ion etching, electron beam lithography, and atomic force microscopy processing. These methods can manufacture nanochannels with higher precision, but they rely on clean rooms and professional equipment. The expensive equipment and consumables cost limits its practicality, resulting in various devices based on 10-nanometer channels being difficult to be widely used. Therefore, it is of great scientific significance and commercial value to design and develop a low-cost, clean-room-free, simple-equipment, and easy-to-operate method for manufacturing 10-nanometer channels. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template, comprising the following steps:

[0005] 1. PDMS micron channel substrate manufacturing

[0006] (1) PDMS (Polydimethylsiloxane) prepolymer and curing agent are mixed in proportion, stirred thoroughly and defoamed, poured onto a glass slide after defoaming, heated to cure the PDMS, and cut into PDMS substrates after cooling;

[0007] (2) etching a micron channel on the surface of the PDMS substrate, and forming two through holes at both ends of the micron channel as liquid reservoirs of the micron channel;

[0008] (3) ultrasonically cleaning the cut PDMS substrate, then rinsing it with deionized water, and drying it to finally form a PDMS micron channel substrate;

[0009] 2. Carbon Nanotube Mold Manufacturing

[0010] (1) Pour the carbon nanotubes into a DMF (Dimethyl Formamide) solution and stir with a magnetic stirrer to prepare a carbon nanotube solution with a concentration of 0.5% to 1.5%;

[0011] (2) treating the channel side of the PDMS micron channel substrate prepared in step 1 with oxygen plasma, and attaching the channel side of the treated PDMS micron channel substrate to a clean glass slide to form a closed micron channel; dripping carbon nanotube solutions into two liquid reservoirs respectively, and the solutions will automatically flow into the micron channel due to capillary action;

[0012] (3) placing the PDMS micron channel substrate in a glass culture dish, and placing the glass culture dish in an ultrasonic cleaning machine; connecting one of the liquid reservoirs of the PDMS micron channel substrate to the positive electrode of a DC power supply, and connecting the other liquid reservoir to the negative electrode of a DC power supply, applying a pulsed AC voltage of 2-3 V / cm, and the voltage frequency is between 5-10 Hz; turning on the ultrasonic cleaning machine and performing ultrasonic treatment, the power of ultrasonic cleaning is 30-40 watts, and the temperature is between 50-60 degrees Celsius; after DMF is completely evaporated, oriented and uniformly distributed carbon nanotubes can be formed in the micron channel, and finally a carbon nanotube mold is formed with the PDMS micron channel substrate;

[0013] 3. Fabrication of PDMS Nanochannel Fluidic Devices

[0014] (1) PDMS prepolymer and curing agent are mixed in proportion, stirred thoroughly and then defoamed, poured onto a carbon nanotube mold after defoaming, heated to cure the PDMS, and after curing, the PDMS is peeled off from the carbon nanotube mold, the shape of the carbon nanotube is copied, and cut to form a PDMS cover plate, at which point the surface of the PDMS cover plate has nanoscale channels of the same size as the carbon nanotubes;

[0015] (2) Prepare another PDMS substrate by referring to the method in step 1 (1), and etch a double U-shaped micron channel on the surface of the PDMS substrate, wherein the distance between the bottom edges of the two U-shaped micron channels is less than 20 microns, and etch two through holes at both ends of the micron channel to form a liquid reservoir of the micron channel;

[0016] (3) ultrasonically cleaning the cut PDMS substrate, then rinsing it with deionized water, and drying it to finally form a PDMS substrate;

[0017] (4) The channel-carrying side of the PDMS substrate and the PDMS cover plate is treated with oxygen plasma, and then bonded to each other after the treatment, and then baked to form a PDMS fluidic device with nanochannels.

[0018] In step 1 (1), the PDMS prepolymer and the curing agent are prepared in a weight ratio of 10:1; the defoaming treatment is carried out in a vacuum oven, and the process parameters are: vacuum degree 200-300 Pa, vacuuming time 20-30 minutes; heating curing process parameters are: temperature 85-90 degrees Celsius, heating time 40-50 minutes.

[0019] In step 1 (2), laser cutting is used to ablate the surface of the PDMS substrate to form a micron channel and a liquid reservoir. The micron channel is 80-100 microns wide, 10-20 microns deep, and 0.5-1.5 cm long. The laser cutting parameters of the micron channel are: ablation power of 10 watts and ablation speed of 2 cm / s. The diameter of the liquid reservoir is 2-3 mm. The laser cutting parameters of the liquid reservoir are: ablation power of 40 watts and ablation speed of 1 cm / s.

[0020] In step 1 (3), the cut PDMS substrate is ultrasonically cleaned using acetone and ethanol solutions, respectively, with an ultrasonic power of 50-60 watts and an ultrasonic time of 15-20 minutes; the drying process is: drying in an oven at 100-150 degrees Celsius for 30-40 minutes.

[0021] In step 2 (1), the purity of the DMF solution is 97%-100%; the stirring parameters of the magnetic stirrer are: rotation speed 20-30 rpm, stirring for 1-1.5 hours; the carbon nanotubes are carboxylated multi-walled carbon nanotubes with an outer diameter of 2-20 nanometers.

[0022] In step 2 (2), the oxygen plasma treatment power is 20-30 watts, the vacuum degree is 70-100 Pa, and the treatment time is 20-30 seconds.

[0023] In step 3 (1), the PDMS prepolymer and the curing agent are prepared in a weight ratio of 10:1; the defoaming treatment is carried out in a vacuum oven, and the process parameters are: vacuum degree 100-150 Pa, vacuuming time 50-60 minutes; heating curing process parameters are: curing temperature 85-90 degrees Celsius, heating time 40-50 minutes.

[0024] In step 3 (2), laser cutting is used to ablate a double U-shaped micron channel and a liquid reservoir on the surface of the PDMS substrate. The micron channel width is 80-100 microns and the depth is 10-20 microns. The laser cutting parameters of the micron channel are: ablation power of 10 watts and ablation speed of 2 cm / s. The diameter of the liquid reservoir is 2-3 mm. The laser cutting parameters of the liquid reservoir are: ablation power of 40 watts and ablation speed of 1 cm / s.

[0025] In step three (3), the cut PDMS substrate is ultrasonically cleaned using acetone and ethanol solutions, respectively, with an ultrasonic power of 50-60 watts and an ultrasonic time of 15-20 minutes; the drying process is: drying in an oven at 100-150 degrees Celsius for 30-40 minutes.

[0026] In step three (4), the oxygen plasma treatment parameters are: power of 20-30 watts, vacuum degree of 70-100 Pa, and treatment time of 20-30 seconds; the baking parameters are: temperature of 200-250 degrees Celsius, and baking time of 0.5-1 minute.

[0027] Beneficial effects of the present invention:

[0028] The present invention utilizes carbon nanotubes to form a uniform and orderly arrangement of carbon nanotubes under ultrasound and alternating electric fields, and forms nanochannels after PDMS pouring. Compared with the existing nanochannel production method, the present invention has the advantages of simple manufacturing process, convenient operation, and lower cost. Nanoscale channels that meet the requirements can be prepared by precisely controlling various parameters without relying on clean room equipment. It provides a reference for the preparation of 10-nanometer scale channels, which is conducive to the application and promotion of nanoscale channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the PDMS micron channel substrate structure of the present invention;

[0030] Figure 2 This is a schematic diagram of the structure of the carbon nanotube mold of the present invention;

[0031] Figure 3 It is a schematic diagram of the PDMS substrate structure of the present invention.

[0032] 1. PDMS micron channel substrate 2. liquid reservoir 3. micron channel 4. carbon nanotube 5. carbon nanotube mold 6. U-shaped micron channel 7. PDMS substrate. DETAILED DESCRIPTION

[0033] See also Figure 1-3 As shown:

[0034] The present invention provides a method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template, comprising the following steps:

[0035] 1. Fabrication of PDMS micron channel substrate 1

[0036] (1) PDMS prepolymer and curing agent are prepared in a weight ratio of 10:1, poured into a disposable plastic cup, stirred thoroughly, and then placed in a vacuum oven for defoaming treatment. The defoaming process parameters are: vacuum degree 200-300 Pa, vacuuming time 20-30 minutes; after defoaming, pour it onto a glass slide (wrapped with transparent tape on all sides), heat to cure the PDMS, and the heating curing process parameters are: temperature 85-90 degrees Celsius, heating time 40-50 minutes; after cooling, peel the cured PDMS from the glass slide and cut it into 2 cm wide, 3 cm long, and 2-3 mm thick PDMS substrates;

[0037] (2) Using laser cutting, a micron channel 3 with a width of 80-100 μm, a depth of 10-20 μm, and a length of 1-1.5 cm is formed on the surface of the PDMS substrate. The laser cutting parameters of the micron channel 3 are: ablation power of 10 W, ablation speed of 2 cm / s; two through holes with a diameter of 2-3 mm are ablated at both ends of the micron channel by laser cutting to form a liquid reservoir 2 of the micron channel. The laser cutting parameters of the liquid reservoir 2 are: ablation power of 40 W, ablation speed of 1 cm / s;

[0038] (3) using acetone and ethanol solutions to ultrasonically clean the cut PDMS substrate, respectively, with the ultrasonic power of 50-60 watts and the ultrasonic time of 15-20 minutes; then rinsing with deionized water and drying in an oven at 100-150 degrees Celsius for 30-40 minutes, finally forming a PDMS micron channel substrate 1;

[0039] 2. Manufacturing of Carbon Nanotube Mold 5

[0040] (1) Pour carbon nanotubes into a DMF solution, and stir the mixture at a speed of 20-30 rpm for 1-1.5 hours using a magnetic stirrer to prepare a carbon nanotube solution with a concentration of 1%; the carbon nanotubes are carboxylated multi-walled carbon nanotubes with an outer diameter of 2-20 nanometers;

[0041] (2) treating the channel side of the PDMS micron channel substrate prepared in step 1 with oxygen plasma, wherein the oxygen plasma treatment power is 20-30 watts, the vacuum degree is 70-100 Pa, and the treatment time is 20-30 seconds; attaching the channel side of the treated PDMS micron channel substrate to a clean glass slide to form a closed micron channel; taking a 10 μl volume of carbon nanotube solution, dropping 5 μl of the carbon nanotube solution into each of the two liquid reservoirs, and the solution will automatically flow into the micron channel due to capillary action;

[0042] (3) Place the PDMS micron channel substrate in a glass culture dish, and place the glass culture dish in an ultrasonic cleaning machine; connect one of the liquid reservoirs of the PDMS micron channel substrate to the positive electrode of a DC power supply, and the other liquid reservoir to the negative electrode of a DC power supply, and apply a pulsed AC voltage of 2-3 V / cm, with a voltage frequency between 5-10 Hz. The frequency cannot be too high, otherwise the carbon nanotubes will be concentrated together; turn on the ultrasonic cleaning machine and perform ultrasonic treatment. The power of ultrasonic cleaning is 30-40 watts, and the temperature is between 50-60 degrees Celsius; under the pulsed AC voltage, the carbon nanotubes 4 are acted upon by the dielectrophoretic force and will be arranged longitudinally along the micron channel. At the same time, due to the ultrasonic effect, the carbon nanotubes 4 will be evenly distributed laterally in the micron channel; after DMF is completely evaporated, oriented and evenly distributed carbon nanotubes 4 can be formed in the micron channel, and finally form a carbon nanotube mold 5 with the PDMS micron channel substrate;

[0043] 3. Fabrication of PDMS Nanochannel Fluidic Devices

[0044] (1) PDMS prepolymer and curing agent are prepared in a weight ratio of 10:1, poured into a disposable plastic cup, stirred thoroughly, and then placed in a vacuum oven for defoaming treatment. The defoaming process parameters are: vacuum degree 100-150 Pa, vacuuming time 50-60 minutes; after defoaming, pour it onto a carbon nanotube mold (wrapped with transparent tape on all sides), heat to cure the PDMS, and the heating curing process parameters are: curing temperature 85-90 degrees Celsius, heating time 40-50 minutes; after curing, peel off the PDMS from the carbon nanotube mold, copy the shape of the carbon nanotube, and cut it with a knife to 2 cm wide, 3 cm long, and 2-3 mm thick to form a PDMS cover plate. At this time, the surface of the PDMS cover plate has nanoscale channels with the same size as the carbon nanotubes;

[0045] (2) Prepare another PDMS substrate by referring to the method in step 1 (1), and form a double U-shaped micron channel 6 on the surface of the PDMS substrate by laser cutting and ablation. The micron channel width is 80-100 μm, the depth is 10-20 μm, and the distance between the bottom edges of the two U-shaped micron channels 6 is less than 20 μm. The micron channel laser cutting parameters are: ablation power of 10 W, ablation speed of 2 cm / s; two through holes with a diameter of 2-3 mm are ablated at both ends of the micron channel by laser cutting to form a liquid reservoir of the micron channel. The liquid reservoir laser cutting parameters are: ablation power of 40 W, ablation speed of 1 cm / s;

[0046] (3) using acetone and ethanol solutions to ultrasonically clean the cut PDMS substrate, respectively, with the ultrasonic power of 50-60 watts and the ultrasonic time of 15-20 minutes; then rinsing with deionized water and drying in an oven at 100-150 degrees Celsius for 30-40 minutes, finally forming a PDMS substrate 7;

[0047] (4) The channel-carrying side of the PDMS substrate and the PDMS cover plate is subjected to oxygen plasma treatment, and the oxygen plasma treatment parameters are: power 20-30 watts, vacuum degree 70-100 Pa, and treatment time 20-30 seconds; after treatment, they are bonded, and the nanoscale channel on the PDMS cover plate corresponds to the bottom edge of the double U-shaped micron channel on the PDMS substrate 7, and is perpendicular to the bottom edge of the double U-shaped micron channel. After baking, a PDMS fluidic device with a nanochannel is formed, and the baking parameters are: temperature 200-250 degrees Celsius, and baking time 0.5-1 minute.

[0048] Both the PDMS prepolymer and the curing agent are commercially available products. The PDMS prepolymer and the curing agent in this embodiment are finished products produced by Dow Corning.

Claims

1. A method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template, characterized in that: The following steps are involved:

1. PDMS micron channel substrate manufacturing (1) PDMS prepolymer and curing agent are mixed in proportion, stirred thoroughly and defoamed, poured onto a glass slide after defoaming, heated to cure the PDMS, and cut into PDMS substrates after cooling; (2) etching a micron channel on the surface of the PDMS substrate, and forming two through holes at both ends of the micron channel as liquid reservoirs of the micron channel; (3) ultrasonically cleaning the cut PDMS substrate, then rinsing it with deionized water, and drying it to finally form a PDMS micron channel substrate; 2. Carbon Nanotube Mold Manufacturing (1) Pour carbon nanotubes into a DMF solution and stir with a magnetic stirrer to prepare a carbon nanotube solution with a concentration of 0.5% to 1.5%; (2) treating the channel side of the PDMS micron channel substrate prepared in step 1 with oxygen plasma, and attaching the channel side of the treated PDMS micron channel substrate to a clean glass slide to form a closed micron channel; dripping carbon nanotube solutions into two liquid reservoirs respectively, and the solutions will automatically flow into the micron channel due to capillary action; (3) Place the PDMS micron channel substrate in a glass culture dish, and place the glass culture dish in an ultrasonic cleaning machine; connect one of the liquid reservoirs of the PDMS micron channel substrate to the positive electrode of a DC power supply, and the other liquid reservoir to the negative electrode of a DC power supply, and apply a pulsed AC voltage of 2-3 V / cm, with a voltage frequency between 5-10 Hz; turn on the ultrasonic cleaning machine and perform ultrasonic treatment, with an ultrasonic cleaning power of 30-40 W and a temperature between 50-60 degrees Celsius; after DMF is completely evaporated, a carbon nanotube mold is formed; 3. Fabrication of PDMS Nanochannel Fluidic Devices (1) PDMS prepolymer and curing agent are mixed in proportion, fully stirred and defoamed, poured onto the carbon nanotube mold after defoaming, heated to cure the PDMS, and after curing, the PDMS is peeled off from the carbon nanotube mold and cut to form a PDMS cover plate; (2) Prepare another PDMS substrate by referring to the method in step 1 (1), and etch a double U-shaped micron channel on the surface of the PDMS substrate, wherein the distance between the bottom edges of the two U-shaped micron channels is less than 20 microns, and etch two through holes at both ends of the micron channel to form a liquid reservoir of the micron channel; (3) ultrasonically cleaning the cut PDMS substrate, then rinsing it with deionized water, and drying it to finally form a PDMS substrate; (4) The channel-carrying side of the PDMS substrate and the PDMS cover plate is treated with oxygen plasma, and then bonded to each other after the treatment, and then baked to form a PDMS fluidic device with nanochannels.

2. The method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template according to claim 1, characterized in that: In step 1 (1), the PDMS prepolymer and the curing agent are prepared in a weight ratio of 10:1; the defoaming treatment is carried out in a vacuum oven, and the process parameters are: vacuum degree 200-300 Pa, vacuuming time 20-30 minutes; heating curing process parameters are: temperature 85-90 degrees Celsius, heating time 40-50 minutes.

3. The method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template according to claim 1, characterized in that: In step 1 (2), laser cutting is used to ablate the surface of the PDMS substrate to form a micron channel and a liquid reservoir. The micron channel is 80-100 microns wide, 10-20 microns deep, and 0.5-1.5 cm long. The laser cutting parameters of the micron channel are: ablation power of 10 watts and ablation speed of 2 cm / s. The diameter of the liquid reservoir is 2-3 mm. The laser cutting parameters of the liquid reservoir are: ablation power of 40 watts and ablation speed of 1 cm / s.

4. The method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template according to claim 1, characterized in that: In step 1 (3), the cut PDMS substrate is ultrasonically cleaned using acetone and ethanol solutions, respectively, with an ultrasonic power of 50-60 watts and an ultrasonic time of 15-20 minutes; the drying process is: drying in an oven at 100-150 degrees Celsius for 30-40 minutes.

5. The method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template according to claim 1, characterized in that: In step 2 (1), the purity of the DMF solution is 97%-100%; the stirring parameters of the magnetic stirrer are: rotation speed 20-30 rpm, stirring for 1-1.5 hours; the carbon nanotubes are carboxylated multi-walled carbon nanotubes with an outer diameter of 2-20 nanometers.

6. The method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template according to claim 1, characterized in that: In step 2 (2), the oxygen plasma treatment power is 20-30 watts, the vacuum degree is 70-100 Pa, and the treatment time is 20-30 seconds.

7. The method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template according to claim 1, characterized in that: In step 3 (1), the PDMS prepolymer and the curing agent are prepared in a weight ratio of 10:1; the defoaming treatment is carried out in a vacuum oven, and the process parameters are: vacuum degree 100-150 Pa, vacuuming time 50-60 minutes; heating curing process parameters are: curing temperature 85-90 degrees Celsius, heating time 40-50 minutes.

8. The method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template according to claim 1, characterized in that: In step three (2), laser cutting is used to ablate a double U-shaped micron channel and a liquid reservoir on the surface of the PDMS substrate. The micron channel width is 80-100 microns and the depth is 10-20 microns. The micron channel laser cutting parameters are: ablation power 10 watts and ablation speed 2 cm / s. The diameter of the liquid reservoir is 2-3 mm. The liquid reservoir laser cutting parameters are: ablation power 40 watts and ablation speed 1 cm / s.

9. The method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template according to claim 1, characterized in that: In step three (3), the cut PDMS substrate is ultrasonically cleaned using acetone and ethanol solutions, respectively, with an ultrasonic power of 50-60 watts and an ultrasonic time of 15-20 minutes; the drying process is: drying in an oven at 100-150 degrees Celsius for 30-40 minutes.

10. The method for manufacturing a nanoscale channel fluidic device based on a carbon nanotube template according to claim 1, characterized in that: In step three (4), the oxygen plasma treatment parameters are: power 20-30 watts, vacuum degree 70-100 Pa, treatment time 20-30 seconds; baking parameters are: temperature 200-250 degrees Celsius, baking time 0.5-1 minute.

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