Method for preparing intrinsic carbon nanotube arrays based on degradable polymers and microfluidic channels

Abstract

The application discloses a method for preparing intrinsic carbon nanotube arrays based on degradable polymers and microfluidic channels. A conjugated polymer containing degradable groups is used to separate and prepare a high-purity semiconductor carbon nanotube solution, and based on the solution, a microfluidic two-phase limited self-assembly method is used to simultaneously prepare high-density carbon nanotube arrays on two substrates. Subsequently, a weak acid solvent is used to decompose the degradable polymer wrapped on the surface of the carbon nanotube into small molecules, and through subsequent cleaning, annealing and other processes, the degradable polymer is completely removed from the surface of the carbon nanotube, so that the intrinsic carbon nanotube arrays with high semiconductor purity, high density and no polymer wrapping on the surface are obtained. The method lays a material foundation for realizing the ultimate performance of the carbon nanotube, and is favorable for early application of carbon nanotube electronic technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of carbon nanotube electronics, and particularly to a method for preparing intrinsic semiconductor carbon nanotube arrays based on degradable polymers and microfluidic channels. BACKGROUND

[0002] Semiconductor carbon nanotubes (s-CNTs) have excellent electrical, thermal and mechanical properties, are compatible with traditional semiconductor processes, and have broad application prospects in the field of future electronics. However, there are still great challenges from theoretical and experimental research to industrial application, and the most critical bottleneck problem is the preparation of carbon nanotube materials. Currently, the batch-produced carbon nanotube materials are a mixture of metallic and semiconducting carbon nanotubes, and the metallic carbon nanotubes will cause the reduction of the device on-off ratio and the degradation of the device performance, so it is necessary to separate the two to obtain semiconducting carbon nanotube materials. In addition, semiconducting carbon nanotubes tend to arrange in a network shape when forming a film, and there are a large number of carbon tube-carbon tube junctions on the channel path, which inevitably reduces the on-state current of the device and leads to the reduction of circuit speed. To manufacture large-scale integrated circuits, the ideal carbon nanotube material is a high-density array of high-purity semiconducting carbon nanotubes deposited on the surface of the carbon nanotube without impurities, maintaining its intrinsic properties.

[0003] The existing methods for large-scale preparation of carbon nanotube arrays mainly include confined self-assembly method and two-dimensional nematic tangential flow self-organization method, which can realize the preparation of wafer-level carbon nanotube arrays. The confined self-assembly method enriches carbon nanotubes at the interface of two incompatible solvents, and forms an array on the substrate surface during the upward pulling process of the substrate. However, this method cannot confine carbon nanotubes in the direction perpendicular to the substrate, so it needs very slow pulling speed to ensure the orientation consistency of the carbon nanotube array. The two-dimensional nematic tangential flow self-assembly method uses the channel formed by two substrates to confine the flowing carbon nanotube solution in the upper layer, and enriches carbon nanotubes at the two-phase interface formed by the lower layer water and the upper layer carbon nanotube solution, to form an array on the substrate surface during the upward pulling process of the substrate. This method has a fast pulling speed of the substrate, but it consumes a lot of solution because the upper layer carbon nanotube solution is continuously flowing. Both of these two methods rely on high-purity semiconducting carbon nanotube solution.

[0004] In the preparation of semiconductor carbon nanotube solution, the conjugated polymer wrapping method has the advantages of high selectivity, high yield, less equipment, short process time, easy scale-up preparation, etc. and is widely used. The commonly used conjugated polymers at present include polyfluorene, polycarbazole and polythiophene and its derivatives, etc., but these polymers are difficult to remove from the surface of carbon nanotubes after the semiconductor carbon nanotubes are separated, especially when the carbon nanotubes are formed into a film on the substrate, which becomes an impurity on the surface of the carbon nanotubes and affects the performance of the device. Although there are reports of using degradable conjugated polymers to prepare semiconductor carbon nanotube solution, whether these carbon nanotube solutions can be used for the preparation of carbon nanotube array and whether the polymer wrapped on the surface of the carbon nanotube can be effectively removed after being formed into a film on the substrate has not been reported, which shows that the degradable conjugated polymer and the preparation of carbon nanotube array must be combined into an organic whole to be considered, so as to solve the problems faced by the current carbon nanotube electronic technology. SUMMARY

[0005] To solve the above problems, the present application proposes a method for preparing intrinsic carbon nanotube array based on degradable polymer and micro-channel, which specifically comprises the following steps:

[0006] Step one: based on degradable conjugated polymer and carbon nanotube raw material, a semiconductor carbon nanotube solution with a first phase organic solvent is prepared;

[0007] Step two: vertically immerse the opposite two substrates into the above semiconductor carbon nanotube solution prepared in step one to form a limited micro-channel between the two substrates, and then drop a second phase solvent incompatible with the above semiconductor carbon nanotube solution into the micro-channel;

[0008] Step three: carbon nanotube array is formed by self-assembly of carbon nanotube at the three-phase interface of the two substrates and the two-phase solution through upward pulling;

[0009] Step four: the above carbon nanotube array obtained in step three is cleaned in a weak acid solution, and is soaked and cleaned in the cleaning solvent and annealed to obtain an intrinsic carbon nanotube array.

[0010] In the embodiments of the present application, the molecular main chain structure of the above degradable conjugated polymer includes fluorene group or carbazole, benzene ring or aromatic heterocycle and imine bond C=N.

[0011] In the embodiments of the present application, the degradable conjugated polymer has a general formula (1):

[0012]

[0013] In the general formula (1), n is the number of repeating units of the polymer, and Ar1 and Ar2 are selected from one or more of the following aromatic structures:

[0014]

[0015] wherein one of Ar1 and Ar2 is Q1 or Q2, and the other is selected from Q1, Q2, Q3, Q4, Q5, Q6 or Q7, and R1 or R2 is C n H 2n+1 wherein 0≤n≤30, preferably 0≤n≤12.

[0016] In the embodiment of the present application, the mass ratio of the above-mentioned degradable conjugated polymer to the above-mentioned carbon nanotube raw material is 0.5:1-3:1, preferably 1:1.

[0017] In the embodiment of the present application, the above-mentioned first-phase organic solvent is selected from any one or more of dichloromethane, chloroform, dichloroethane, dichloropropane, trichloromethane and trichloroethane.

[0018] In the embodiment of the present application, the above-mentioned second-phase organic solvent contains a hydroxyl group and a double bond, and is immiscible with the carbon nanotube.

[0019] In the embodiment of the present application, the above-mentioned second-phase organic solvent is selected from any one or more of ethylene glycol, glycerol, 1,4-butanediol, 2-pentene-1,5-diol, 1,5-hexadiene-3,4-diol or 2,4-hexadiene-1,6-diol.

[0020] In the embodiment of the present application, the above-mentioned weakly acidic solution is prepared by adding a certain amount of acid into a toluene, tetrahydrofuran or chloroform organic solvent, and the above-mentioned acid is selected from any one or more of trifluoroacetic acid, triflic acid, acetic acid, hydrofluoric acid, hydrochloric acid, sulfuric acid or nitric acid.

[0021] In the embodiment of the present application, the above-mentioned cleaning solvent is selected from any one or more of toluene, xylene, DMF or THF.

[0022] In the embodiment of the present application, the above-mentioned annealing is vacuum annealing or atmosphere annealing.

[0023] The micro-channel confined self-assembly method provided by the present application utilizes the interface formed by the upper and lower phase solutions to enrich the carbon nanotubes, wherein the carbon nanotube solution is in the lower layer, but the micro-channel formed by narrowing the distance between the two substrates further limits the lateral movement of the interface carbon tubes, which is conducive to controlling the orientation of the carbon tubes in the process of high-speed pulling, and saves the carbon nanotube solution.

[0024] Simultaneously, this invention uses a designed biodegradable conjugated polymer to replace the non-biodegradable conjugated polymer, achieving not only the preparation of a high-purity semiconductor carbon nanotube solution, but also, using the prepared carbon nanotube solution, employing the invented microfluidic two-phase confined self-assembly method to simultaneously fabricate a high-semiconductor-purity, high-density carbon nanotube array on two opposing substrates. Based on the characteristics of the designed and used biodegradable conjugated polymer, a weakly acidic solvent is used to degrade the biodegradable conjugated polymer coated on the carbon nanotube surface into small molecules. Combined with subsequent cleaning and annealing processes, the polymer coating on the carbon nanotube surface is effectively removed, yielding an intrinsic carbon nanotube array. Attached Figure Description

[0025] The above and other objects, features and advantages of the present invention will become clearer from the following description of the technical solution of the present invention with reference to the accompanying drawings, in which:

[0026] Figure 1 This is a flowchart illustrating the steps involved in preparing intrinsic semiconductor carbon nanotubes according to an embodiment of the present invention.

[0027] Figure 2 The NMR spectrum of the biodegradable conjugated polymer prepared in the embodiments of the present invention;

[0028] Figure 3 The molecular weight and distribution spectrum of the conjugated polymers prepared in the embodiments of the present invention;

[0029] Figure 4 The UV-Vis absorption spectra of the conjugated polymer prepared in the embodiments of the present invention before and after acid addition;

[0030] Figure 5 The absorption spectrum of the polymer P1 separating semiconductor carbon nanotube solution is shown in the embodiment of the present invention.

[0031] Figure 6 This is a SEM image of a semiconductor carbon nanotube array prepared using polymer P1 before the polymer coating is removed, as described in an embodiment of the present invention.

[0032] Figure 7 This is a SEM image of a semiconductor carbon nanotube array prepared using polymer P1 after removing the polymer coating, as described in an embodiment of the present invention.

[0033] Figure 8 This is a TEM image of a semiconductor carbon nanotube before the removal of its encapsulated polymer, as described in an embodiment of the invention.

[0034] Figure 9 This is a TEM image of a semiconductor carbon nanotube after the polymer coating process was removed, as described in an embodiment of the invention. Detailed Implementation

[0035] Embodiments of the present application will be described in detail below with reference to the drawings. In the drawings, like elements are denoted by like reference numerals, and various parts of the drawings are not drawn to scale. Also, certain known parts can not be shown.

[0036] As shown in Figure 1 The present embodiment proposes a method for preparing intrinsic carbon nanotube arrays based on degradable polymers and microfluidic channels, which specifically comprises the following steps:

[0037] Step one: dissolve the degradable conjugated polymer in toluene solution, then add carbon nanotube raw materials, and then perform ultrasonic crushing and centrifugation, wherein the ultrasonic crushing power is 50-300W, the time is 10-60min, the duty cycle is 20%-80%, the temperature is -50-40 degrees Celsius, the centrifugal force is 10000g-50000g, the time is 20min-120min, and the temperature is -10-30 degrees Celsius; the mass ratio of the degradable conjugated polymer to the carbon nanotube raw materials is 1:1, and in other embodiments, the mass ratio of the degradable conjugated polymer to the carbon nanotube raw materials can be in the range of 0.5:1-3:1. After centrifugation, 90% of the supernatant is taken to obtain a high-purity semiconductor carbon nanotube solution. Then, high-purity semiconductor carbon nanotube precipitates are obtained by rotary evaporation or long-time high-speed centrifugation, and are dissolved in a first-phase organic solvent to obtain a high-purity semiconductor carbon nanotube solution. In this embodiment, the first-phase organic solvent is dichloromethane, and in other embodiments, the first-phase organic solvent is any one or more of chloroform, dichloromethane, dichloroethane, dichloropropane, trichloromethane, and trichloroethane, which have high density and strong polarity, can deposit at the bottom when the two phases are layered, and can well dissolve the carbon nanotube solution.

[0038] In this embodiment, the degradable conjugated polymer includes fluorene groups or carbazole, benzene rings or aromatic heterocyclic rings, and imine bonds C=N in the molecular backbone structure of the degradable conjugated polymer.

[0039] In the embodiments of the present application, the degradable conjugated polymer has the general formula (1):

[0040]

[0041] In the general formula (1), n is the number of repeating units of the polymer, and Ar1 and Ar2 are selected from one or more of the following aromatic structures:

[0042]

[0043] wherein one of Ar1 and Ar2 is Q1 or Q2, and the other is selected from Q1, Q2, Q3, Q4, Q5, Q6, or Q7, and R1 or R2 is C n H 2n+1wherein 0≤n≤30, preferably 0≤n≤12.

[0044] In this embodiment, the above-mentioned degradable conjugated polymer can be prepared by the following method: preparing the degradable conjugated polymer by carrying out nucleophilic addition reaction of the fluorene diamine and bipyridine dialdehyde in an organic solvent.

[0045]

[0046] In order to ensure the conjugated structure of the main chain, the main chain structure containing fluorenyl and bipyridine is designed in this embodiment, and a meta imine bond is introduced into the main chain. The specific preparation method includes the following steps:

[0047] Under room temperature and nitrogen gas protection, 212.2 milligrams (1 mmol) of 2,2’-bipyridine-5,5’-diformaldehyde (M2) and 30 grams of toluene are added into a three-necked flask equipped with magnetic stirring, thermometer and condenser tube, and stirred until completely dissolved; in other embodiments, 2,2’-bipyridine-5,5’-diformaldehyde can also be added into dimethylbenzene, dimethylformamide, dichloromethane or chloroform for stirring and dissolving. 420.69 milligrams (1 mmol) of 2,7-diamino-9,9’-n-octylfluorene (M1) is added, and the initial solid content is 2wt%. After complete dissolution, 2 grams of anhydrous lithium chloride is added as a water absorbent. In other embodiments, the water absorbent can also be selected from anhydrous calcium chloride, sodium bicarbonate or molecular sieve.

[0048] In this embodiment, the molar ratio of M1 and M2 is 1:1. In other embodiments, the molar ratio of M1 and M2 is (0.95-1.02):1, and the initial solid content is 1%-10%.

[0049] After stirring the above-mentioned solution at room temperature for 12 hours, 3 milligrams of salicylaldehyde is added, and the temperature is raised to 110°C for refluxing for 4h. In other embodiments, the stirring time at room temperature can be 2-24h, and the heating and stirring time for the temperature raising and refluxing is 1-12h.

[0050] After the reaction is completed, the lithium chloride is removed by filtration with a filter membrane to obtain a yellow clear filtrate. After adding an equivalent amount of methanol into the filtrate and stirring and standing, recrystallization is carried out to make the yellow precipitate separate out. After filtration with a filter membrane and vacuum drying, a yellow powder is obtained, which is the degradable conjugated polymer P1. In other embodiments, the recrystallization can be carried out by rotary evaporation of the filtrate.

[0051] Degradation test: the above-mentioned P1 is dissolved in toluene to obtain a yellow solution. After adding 3% trifluoroacetic acid (TFA), the color of the solution rapidly becomes lighter to almost colorless, and the surface polymer decomposes.

[0052] Figure 2 is the nuclear magnetic resonance spectrum of P1, 1H NMR (300 MHz, Chloroform-d), 10.19 (s,

[0053] 1H), 8.88-8.85 (m, 1H), 8.65-8.62 (m, 1H), 8.38-8.35 (m, 1H), 8.05-8.03 (m, 2H), 7.79 -7.76 (m, 2H), 7.39-7.38 (m, 4H), 2.05-1.89 (m, 4H), 1.25-0.97 (m, 20H), 0.82 -0.78 (m, 10H); Figure 3 is the molecular weight and its distribution chart, wherein Mn = 27848 g / mol, Mw = 55121 g / mol, PDI = 2. From the above chart, it can be seen that the final preparation obtained a high molecular weight target polymer.

[0054] Figure 4 is the UV-visible light absorption spectrum of the toluene solution of the prepared polymer P1, the absorption spectrum of the solution after adding TFA for 1 min, and the absorption spectrum of the toluene solution of the two monomers M1 and M2 required for preparing P1. As can be seen from the chart, the P1 solution has an absorption peak at 430 nm, and after adding TFA, the absorption peak at this position disappears rapidly, and two absorption peaks appear near 300 nm and 320 nm, indicating that P1 has been degraded under acid washing conditions; the toluene solutions of M1 and M2 have absorption peaks at 300 nm and 320 nm, respectively, which can correspond to the two main decomposition products of P1, indicating that P1 has been degraded into monomers, and can be recovered after post-processing.

[0055] Step two: vertically immerse two opposite substrates into the semiconductor carbon nanotube solution prepared in step one, the concentration of carbon nanotubes is 20 μg / mL, and in other embodiments, the concentration of semiconductor carbon nanotubes is 10-50 μg / mL; drop the second phase solvent in the confined microchannel formed between the two opposite substrates, in this embodiment, the width of the microchannel is 1 mm, and in other embodiments, the channel width is 0.5-3 mm, and more preferably in the range of 1-3 mm; due to the interfacial effect, carbon tubes will be enriched at the two-phase interface, and the capillary effect of the channel is more conducive to the enrichment and arrangement of carbon nanotubes on the "pipe wall", that is, the substrate. The above-mentioned second phase organic solvent contains hydroxyl and double bond, and is immiscible with the carbon nanotube solution. In this embodiment, 1,4-butanediol is used as the second phase organic solvent, and in other embodiments, the second phase organic solvent can be selected from any one or more of glycerol, 1,4-butanediol, 2-pentene-1,5-diol, 1,5-hexadiene-3,4-diol or 2,4-hexadiene-1,6-diol.

[0056] Step three: carbon nanotubes are self-assembled into carbon nanotube arrays at the three-phase interface where the two substrates and the two-phase solution meet by pulling up the substrates at a pulling speed of 18 um / s, and in other embodiments, the pulling speed is 1 um / s-50 um / s; compared with the commonly used confined self-assembly method (DLSA), the micro-channel formed by the space between the two substrates in the embodiment reduces the influence of the disturbance of the liquid surface on the array arrangement during the pulling of the substrates, and the defects in the array can be more effectively reduced through temperature and interface field control; compared with the commonly used tangential flow self-assembly method (TaFISA), the method of the embodiment constructs an organic-organic solvent interface, and the carbon nanotube solution does not need to flow to make the carbon nanotubes enriched at the interface, thereby reducing the amount of solution used; in addition, the present application can simultaneously prepare two uniform carbon nanotube arrays, which are stable and efficient, and are conducive to the batch and large-scale preparation of array films.

[0057] Step four: the carbon nanotube array obtained in step three is cleaned in a weak acid solution, which can decompose the polymer wrapped on the surface into small molecules and destroy the conjugation effect of the polymer and the carbon nanotube, and then through the immersion cleaning and annealing of the cleaning solvent, the removal of the polymer on the surface of the carbon nanotube can be effectively realized, and an intrinsic carbon nanotube array is obtained. The above weak acid solution is prepared by adding a small amount of trifluoroacetic acid to toluene. In other embodiments, the above weak acid solution can be prepared by adding any one or more of triflic acid, acetic acid, hydrofluoric acid, hydrochloric acid, sulfuric acid or nitric acid to tetrahydrofuran or chloroform organic solvents. In the embodiment, the cleaning solvent is toluene, and the cleaning temperature is 100℃ / 1h, and in other embodiments, the cleaning solvent is any one or more of DMF, THF, N-methyl pyrrolidone, and the cleaning temperature is 50-110℃, and the cleaning time is 0.5-6h. The above annealing can be vacuum annealing or atmosphere annealing, and the annealing time is 0.5-2h.

[0058] Figure 5 is the ultraviolet-visible light absorption spectrum of the solution of the conjugated polymer separated from arc-discharge carbon nanotubes, from which it can be seen that there is no typical absorption peak of metallic carbon nanotubes M 11 in the carbon nanotube solution between 600-800nm, and there is a typical absorption peak of semiconductor carbon nanotubes S 22 in the carbon nanotube solution between 800-1200nm, indicating that the separated semiconductor carbon nanotube solution has very high semiconductor purity.

[0059] Figure 6 and Figure 7 are the SEM images of the semiconductor carbon nanotube array prepared by using the polymer P1 in the embodiment before and after the wrapped polymer is removed. Figure 8 and Figure 9is the TEM image before and after the removing polymer process of the semiconductor carbon nanotube. It can be seen that the carbon nanotube wall is wrapped by a large amount of polymer before adding acid, and the carbon nanotube wall is not wrapped by polymer and is clear after adding acid.

[0060] The present application uses the designed degradable conjugated polymer to replace the commonly used conjugated polymer, not only realizes the preparation of high-purity semiconductor carbon nanotube solution, but also uses the prepared carbon nanotube solution to prepare high-semiconductor-purity and high-density carbon nanotube arrays on two substrates by using the invented micro-channel two-phase limited self-assembly method. Based on the characteristics of the designed and used degradable conjugated polymer, the degradable conjugated polymer wrapped on the surface of the carbon nanotube is degraded into small molecules by using a weak acid solvent, and the subsequent cleaning and annealing processes are combined to realize the effective removal of the polymer from the surface of the carbon nanotube, and obtain intrinsic carbon nanotube arrays.

[0061] The present application first breaks through the preparation chain from carbon nanotube raw materials to practical high-semiconductor-purity, high-density and polymer-free surface intrinsic carbon nanotube arrays, and lays a material foundation for the practicality of carbon-based electronic technology.

[0062] Although the present application has been described in detail in the foregoing general description, specific implementation, but on the basis of the present application, some modifications or improvements can be made, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application claimed.

Claims

1. A method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microfluidics, characterized in that, Includes the following steps: Step 1: Prepare a semiconductor carbon nanotube solution with the first phase organic solvent as the solvent based on biodegradable conjugated polymer and carbon nanotube raw materials; Step 2: Vertically immerse two opposing substrates into the semiconductor carbon nanotube solution prepared in Step 1 to form a confined microchannel between the two substrates. The width of the microchannel is 1-3 mm. Then, add a second-phase organic solvent that is immiscible with the semiconductor carbon nanotube solution to the microchannel. Step 3: By pulling upwards, carbon nanotubes self-assemble at the three-phase interface where the two substrates and the two-phase solution intersect to form a carbon nanotube array; Step 4: The carbon nanotube array obtained in Step 3 is cleaned in a weakly acidic solution, and then immersed in the cleaning solvent for cleaning and annealing to obtain an intrinsic carbon nanotube array.

2. The method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microchannels according to claim 1, characterized in that, The molecular backbone structure of the biodegradable conjugated polymer includes fluorenyl or carbazole, benzene ring or aromatic heterocycle, and imine bond C=N.

3. The method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microchannels according to claim 2, characterized in that, The biodegradable conjugated polymer has the general formula (1): In general formula (1), n ​​is the number of repeating units in the polymer, and Ar1 and Ar2 are selected from one or more of the following aromatic structures: In this system, one of Ar1 and Ar2 is Q1 or Q2, and the other is selected from Q1, Q2, Q3, Q4, Q5, Q6, or Q7. R1 or R2 is C. n H 2n+1 , where 0≤n≤30.

4. The method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microchannels according to claim 3, wherein R1 or R2 is C n H 2n+1 , 0≤n≤12.

5. The method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microchannels according to claim 1, characterized in that, The mass ratio of the biodegradable conjugated polymer to the carbon nanotube raw material is 0.5:1-3:

1.

6. The method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microchannels according to claim 5, wherein the mass ratio of the biodegradable conjugated polymer to the carbon nanotube raw material is 1:

1.

7. The method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microchannels according to claim 1, characterized in that, The first phase organic solvent is selected from any one or more of dichloromethane, chloroform, dichloroethane, dichloropropane, trichloromethane, and trichloroethane.

8. The method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microchannels according to claim 1, characterized in that, The second phase organic solvent contains hydroxyl groups and double bonds, and is immiscible with carbon nanotubes.

9. The method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microfluidics according to claim 1 or 8, characterized in that, The second phase organic solvent is selected from any one or more of ethylene glycol, glycerol, 1,4-butenediol, 2-penten-1,5-diol, 1,5-hexadien-3,4-diol, or 2,4-hexadien-1,6-diol.

10. The method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microchannels according to claim 1, characterized in that, The weakly acidic solution is prepared by adding a certain amount of acid to an organic solvent such as toluene, tetrahydrofuran, or chloroform. The acid is selected from any one or more of trifluoroacetic acid, trifluoromethanesulfonic acid, acetic acid, hydrofluoric acid, hydrochloric acid, sulfuric acid, or nitric acid.

11. The method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microchannels according to claim 1, wherein the cleaning solvent is selected from any one or more of toluene, xylene, DMF, THF, and N-methylpyrrolidone.

12. The method for preparing intrinsic carbon nanotube arrays based on biodegradable polymers and microchannels according to claim 1, wherein the annealing is vacuum annealing or atmosphere annealing.

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