Method for transferring a carbon nanotube aqueous dispersion into an organic phase dispersion

Abstract

The present application discloses a method for converting a carbon nanotube aqueous dispersion into an organic dispersion. The method includes the steps of: providing a carbon nanotube aqueous dispersion; mixing the carbon nanotube aqueous dispersion with a first solvent containing a hydrophilic organic solvent to obtain a first suspension; mixing the first suspension with a second solvent containing a hydrophobic organic solvent to form two layered phases to obtain a second suspension; mixing the second suspension with a third solvent to obtain a third suspension; dispersing the second suspension or the third suspension to obtain a carbon nanotube organic dispersion, achieving solvent transfer of the carbon nanotubes, and achieving solvent transfer from the aqueous phase to the organic phase of the carbon nanotube dispersion. The method provided by the present application can convert a carbon nanotube aqueous dispersion into an organic dispersion, with a transfer efficiency of 70% to 95%.

Description

[Technical field]

[0001] (Related Applications) This application claims priority to a Chinese patent application filed on November 29, 2022, with application number 202211511672.X and title "Method for transferring carbon nanotube aqueous phase dispersion into organic phase dispersion."

[0002] (Technical field) The present application belongs to the technical field of separation and purification, and specifically relates to a method for transferring a carbon nanotube aqueous phase dispersion into an organic phase dispersion. [Background technology]

[0003] Carbon nanotubes are considered to be the most promising material in nanoscience and technology due to their excellent optical and electrical properties. In recent years, the development of carbon nanotube dispersion and separation technologies that can disperse or separate multi-walled or single-walled carbon nanotubes to some extent has progressed rapidly, such as surfactant-coated aqueous phase systems: density gradient ultracentrifugation, ion exchange chromatography, gel chromatography columns, electrophoresis, and two-phase aqueous phase separation systems. At the same time, carbon nanotubes for different applications need to be dispersed in different solvents or dispersion media. For example, in the application of single-walled carbon nanotubes in the electronics field, it is necessary to reduce the amount of polymers and dispersants so that the Schottky barrier between the tubes and the resistance between the carbon tubes and the electrodes are small in order to improve the performance of single-walled carbon nanotubes in the electronics field. For example, small-diameter chiral carbon tubes, semiconductors, and metal tubes can be easily separated from the aqueous phase, but the surface of carbon tubes is highly surfactant-containing, making separation difficult, which limits their use in optoelectronics. Single-walled carbon nanotubes with higher purity and specific chirality, such as those dispersed in an organic phase, can better meet the application of carbon nanotube optoelectronics. If the multi-walled tubes have good electrical conductivity, it is necessary to add a large number of surfactants to disperse the multi-walled tubes in an aqueous phase, which reduces the electrical conductivity of the multi-walled tubes. For example, multi-walled tubes dispersed in an organic phase have good electrical conductivity. Therefore, in the current system of aqueous phase dispersion, it is expected to be replaced by an organic phase solution, which will better broaden the application prospects of carbon nanotubes.

[0004] To achieve the substitution between carbon nanotube-solution systems, the first goal is to remove as much of the dispersant as possible from the current solution. For example, in aqueous systems where the dispersant on the surface of the carbon tubes is in dynamic equilibrium with the solution, some researchers have tried to remove the surfactant by filtration or dialysis, but these methods cause the carbon tubes to aggregate, and tubes with poor surface cleanliness gather together. The next goal is to redisperse the carbon nanotubes in the solution by using a new solvent and appropriate dispersion conditions to meet the needs of various applications. The current drawbacks are, firstly, that the surfactant on the outside of the carbon tubes cannot be effectively removed, and, secondly, that there are many aggregates between the carbon tubes.

[0005] Few current techniques encompass all these aspects simultaneously. Although many aspects of surfactant removal from aqueous solutions have been studied, the problem of aggregation between carbon tubes has not been studied much. Jamie E. Rossi et al. reported that by collecting single-walled carbon nanotubes through a filtration process and undergoing a combination of organic solvent rinsing and high-temperature treatment steps, the surfactant can be effectively removed, but at the same time, there appears to be a strong interaction force between the carbon tubes, making the system transposition more difficult to achieve; Han Li and co-workers were able to concentrate the carbon tubes through filtration and transpose the aqueous phase to the organic phase through multiple rinsing with ethanol, but the washing process strengthened the aggregation between the carbon tubes, making the transposition process more lossy and time-consuming; Robert Nisler and co-workers used salt layer filtration method to secure carbon tubes from organic phase to aqueous phase, which can not only effectively remove surfactants on carbon tubes, but also reduce the agglomeration of carbon tubes, but also more effective carbon tubes. However, the salt layer filtration method of aqueous phase to organic phase is no longer applicable. However, the above method still has many shortcomings. On the one hand, with the increase in the number of carbon tubes, the time consumption of the filtration process is greatly extended, making it difficult to realize scale-up application. On the other hand, the filtration and washing process will bring about the problem of agglomeration of carbon tubes, and redispersion will result in a high rate of carbon tube loss, which requires a lot of time and energy. Summary of the Invention [Problem to be solved by the invention]

[0006] The main objective of the present application is to provide a method for transferring carbon nanotube aqueous phase dispersions to organic phase dispersions to overcome the deficiencies of the prior art. [Means for solving the problem]

[0007] In order to achieve the above objectives of the invention, the present application adopts the following technical solutions:

[0008] An embodiment of the present application provides a method for converting a carbon nanotube aqueous phase dispersion into an organic phase dispersion, the method comprising: Providing an aqueous dispersion of carbon nanotubes; A step of mixing the carbon nanotube aqueous phase dispersion liquid and a first solvent containing a hydrophilic organic solvent to obtain a first suspension; mixing the first suspension with a second solvent containing a hydrophobic organic solvent to form two layered phases to obtain a second suspension; mixing the second suspension and a third solvent together to obtain a third suspension; The method includes a step of dispersing the second suspension or the third suspension to obtain an organic dispersion of carbon nanotubes, and achieving solvent transfer from the aqueous phase of the carbon nanotube dispersion to the organic phase. Effect of the Invention

[0009] Compared with the prior art, the present application has the following beneficial effects: (1) The present application ensures high purity of carbon nanotubes through the extraction process and the solvent conversion process, while simultaneously transferring the carbon nanotube dispersion from the aqueous phase to the organic phase with a transfer efficiency of 70% to 95%. (2) The method provided by the present application can significantly improve the semiconductivity or monochiral purity of carbon nanotubes in the original aqueous phase when the polymer transferred to the organic phase has certain semiconductivity or narrow chiral separation properties. [Brief description of the drawings]

[0010] In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following briefly describes the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these accompanying drawings without creative labor.

[0011] [Figure 1]1 is a schematic flow chart of a method for converting a carbon nanotube aqueous phase dispersion into an organic phase dispersion in an exemplary embodiment of the present application. [Diagram 2] FIG. 2 is a comparison diagram of XPS test results in Example 1. [Diagram 3] 1 is a schematic flow chart of the process of transferring a HiPCO tube dispersed with DOC from an aqueous phase to an organic phase in Example 1 of the present application. [Figure 4] 1 is a schematic flow chart of the process of transferring TUBALL carbon nanotubes dispersed in Triton x-100 from an aqueous phase to an organic phase in Example 2 of the present application. [Diagram 5] 1 is a schematic flow chart showing a process for transferring a metallic carbon nanotube dispersion liquid from an aqueous phase to an organic phase in Example 4 of the present application. [Figure 6] 1 is a schematic flow chart of a process for improving semiconductor purity by transferring a semiconductor carbon nanotube dispersion from an aqueous phase to an organic phase in Example 5 of the present application. [Figure 7] 1 is a schematic flow chart of a process for transferring a chiral carbon nanotube dispersion from an aqueous phase to an organic phase to achieve chiral separation in Example 6 of the present application. [Figure 8] 1 is a schematic flow chart showing how chiral carbon nanotube dispersion liquid in Example 7 of the present application is transferred from an aqueous phase to an organic phase to achieve chiral separation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In view of the deficiencies of the prior art, the inventor of the present invention, after a long period of research and much practice, has been able to propose the technical solution of the present application, which mainly goes through a series of transition methods: carbon nanotube aqueous phase dispersion → removal of surfactant by extraction method → ​​solvent replacement → organic phase dispersion, thereby achieving smooth and efficient completion of the transition process.

[0013] The technical solutions of the present application will be described below clearly and completely, but obviously, the described embodiments are only some of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative labor are all included in the protection scope of the present application.

[0014] Specifically, in one aspect of the technical solution of the present application, the method for transferring the carbon nanotube aqueous phase dispersion into an organic phase dispersion includes: Providing an aqueous dispersion of carbon nanotubes; A step of mixing the carbon nanotube aqueous phase dispersion liquid and a first solvent containing a hydrophilic organic solvent to obtain a first suspension; mixing the first suspension with a second solvent containing a hydrophobic organic solvent to form two layered phases to obtain a second suspension; mixing the second suspension and a third solvent together to obtain a third suspension; The method includes a step of dispersing the second suspension or the third suspension to obtain an organic dispersion of carbon nanotubes, and achieving solvent transfer from the aqueous phase of the carbon nanotube dispersion to the organic phase.

[0015] In some preferred embodiments, the carbon nanotubes contained in the carbon nanotube aqueous dispersion include, but are not limited to, one or a combination of two or more of single-walled carbon nanotubes, multi-walled carbon nanotubes, and separated carbon nanotubes.

[0016] In some preferred embodiments, the dispersant contained in the carbon nanotube aqueous phase dispersion includes, but is not limited to, an ionic surfactant and / or a non-ionic dispersant.

[0017] Further, the ionic surfactant includes, but is not limited to, any one or a combination of two or more of sodium deoxycholate, sodium cholate, sodium dodecyl sulfate, and sodium dodecylbenzenesulfonate.

[0018] Further, the non-ionic dispersant may include, but is not limited to, any one or a combination of two or more of Triton, lauryl alcohol and oleyl alcohol, Tween, cyclohexanol, nonylphenol, and single-stranded DNA.

[0019] Furthermore, the carbon nanotube aqueous dispersion further contains water-soluble additives introduced in the carbon nanotube separation process, such as dextran, polyethylene glycol, polyacrylamide, polyethylene glycol diamine, and polyvinylpyrrolidone introduced in the double aqueous phase separation process, iodixanol or cesium chloride introduced in the gradient density centrifugation process, and a buffer solution (e.g., sodium chloride solution, sodium hypochlorite solution, sodium thiocyanate solution, etc.) introduced in the DNA separation process.

[0020] In some preferred embodiments, the method specifically includes thoroughly mixing the carbon nanotube aqueous dispersion with a first solvent and allowing it to stand for 1 to 30 minutes, so that at least the surfactant adsorption layer on the surface of the carbon nanotubes is destroyed under the action of the first solvent, and the carbon nanotubes are precipitated and suspended in the mixed solution.

[0021] In some preferred embodiments, the first solvent is an organic solvent that is miscible or partially miscible with water, including, but not limited to, any one, two or a combination of two or more of N,N-dimethylformamide, tetrahydrofuran, dimethylsulfoxide, N-methylpyrrolidone, dioxane, acetone, methyl ethyl ketone, butanone, ethanol, and acetonitrile.

[0022] In some preferred embodiments, the first suspension comprises the carbon nanotube aqueous phase dispersion and a first solvent.

[0023] Furthermore, the volume ratio of water to the first solvent in the first suspension is 1:1 to 1:6.

[0024] In some preferred embodiments, the method specifically includes thoroughly mixing the first suspension and a second solvent and allowing to stand for 1 to 15 minutes to form two phases, and suspending the carbon nanotubes in the second solvent to form the second suspension.

[0025] In some preferred embodiments, the second solvent includes, but is not limited to, any one or a combination of two or more of m-chlorotoluene, toluene, xylene, chlorobenzene, dichloromethane, trichloromethane, and trichloroethane.

[0026] In some preferred embodiments, the volume ratio of the first solvent to the second solvent is 1:0.5 to 1:6.

[0027] In some preferred embodiments, the method specifically includes adding a third solvent to the second suspension, mixing them together, standing to remove the upper transparent liquid, adding a third solvent, mixing and standing to remove the upper transparent liquid, and repeating the above operations 3 to 10 times to obtain the third suspension.

[0028] Furthermore, the volume ratio of the second suspension and the third solvent is 1:3 to 1:8.

[0029] In some preferred embodiments, the third suspension comprises carbon nanotubes and a third solvent, wherein the content of the second solvent in the third suspension is less than 1 (v / v)%.

[0030] In some preferred embodiments, the method specifically includes dispersing the second suspension or the third suspension under dispersant-free conditions to obtain an organic carbon nanotube dispersion, or mixing the second suspension or the third suspension with a dispersant and performing a dispersion process to obtain an organic carbon nanotube dispersion, wherein the dispersant includes an organic dispersant and / or a polymer dispersant.

[0031] In some preferred embodiments, the dispersion method includes, but is not limited to, any one of the following methods: shearing, ultrasonication, homogenizing, sanding, ball milling, high pressure jet, and the like.

[0032] In some preferred embodiments, when the carbon nanotube aqueous dispersion is obtained by dual aqueous phase technique separation, the carbon nanotube aqueous dispersion is first pretreated to remove water-soluble polymers in the carbon nanotube aqueous dispersion.

[0033] Specifically, when the carbon nanotube aqueous phase dispersion is obtained by dual aqueous phase separation, it contains a large amount of water-soluble polymers such as polyethylene glycol and dextran, and it is necessary to carry out a pretreatment to remove these water-soluble polymers before the phase inversion process.

[0034] Further, the water soluble polymer includes, but is not limited to, polyethylene glycol and / or dextran.

[0035] Furthermore, the pretreatment includes mixing a saturated salt solution with the carbon nanotube dispersion and centrifuging the mixture to obtain a coprecipitate of the carbon nanotubes and the surfactant, and then redispersing the coprecipitate of the carbon nanotubes and the surfactant in water to obtain an aqueous dispersion of carbon nanotubes that does not contain a water-soluble polymer.

[0036] Furthermore, the salt in the saturated salt solution includes, but is not limited to, any one or a combination of two or more of ammonium sulfate, sodium sulfate, magnesium sulfate, sodium chloride, and magnesium chloride.

[0037] In some more specific embodiments, the method of converting the carbon nanotube aqueous phase dispersion into an organic phase dispersion (a schematic flow chart of which is shown in FIG. 1 ) comprises: Step 1: The carbon nanotube aqueous phase dispersion liquid and the first solvent are mixed together and allowed to stand for 1 to 30 minutes. Under the action of the first solvent, the surfactant adsorption layer on the carbon tube is destroyed, and the carbon tubes are precipitated and suspended in the solution within 2 to 20 minutes to obtain suspension I (i.e., the above-mentioned "first suspension", the solvent is water and the first solvent, and the suspended matter is carbon nanotubes); Step 2: Add the second solvent to the suspension I, mix them together and let them stand, the solution forms two phases within 1-15 min, the surfactant is extracted into the aqueous phase due to its hydrophilicity, and the carbon tubes are suspended in the organic phase solution due to its hydrophobicity to obtain the suspension II (i.e., the above-mentioned "second suspension", the solvent is the second solvent, and the suspended matter is the carbon nanotubes); Step 3: Add the third solvent to the suspension II, mix and stand, the carbon tubes gradually settle to the bottom of the solution, the carbon tubes are loose and not rapidly aggregated, remove the upper transparent liquid, add the third solvent, mix and stand, repeat this step 3 to 10 times to obtain the suspension III (i.e. the above-mentioned "third suspension", the solvent is the third solvent, and the suspended matter is the carbon nanotubes); Step 4: Suspension II or suspension III is subjected to a dispersion step to obtain an organic dispersion of carbon nanotubes.

[0038] The purpose of this application is to remove the carbon tube surfactant while reducing the aggregation between carbon nanotubes, so that the system phase inversion process is more convenient and efficient. This application provides a method for achieving system phase inversion from an aqueous phase to an organic system by an extraction separation method utilizing the hydrophobicity of carbon nanotubes and the hydrophilicity of surfactants. First, the carbon nanotube aqueous phase dispersion and a first solvent (e.g., N,N-dimethylformamide) are mixed together, the surfactant is dissolved in the first solvent, and the carbon nanotubes are suspended in the solution at the same time. Finally, a second solvent (e.g., m-chlorotoluene) is added, mixed uniformly, and allowed to stand, and the second solvent suspension of pure carbon nanotubes is collected from the bottom phase. Finally, the second solvent carbon nanotube suspension and a third solvent (e.g., xylene) are mixed together, and allowed to stand to remove the upper layer solution. This process is repeated 3 to 10 times to collect the third solvent carbon nanotube suspension. This method has the following advantages: (1) Through the extraction process and the solvent conversion process, the carbon nanotube dispersion is transferred from the aqueous phase to the organic phase with a transfer efficiency of 70% to 95% while ensuring high purity of the carbon nanotubes. (2) By adding a third solvent, the carbon nanotubes in the carbon nanotube second solvent dispersion are precipitated, and the process is repeated 3 to 10 times to remove more than 99% of the second solvent, and the solvent is basically converted into the third solvent. (3) By combining the salting out process and the extraction process, the fine-diameter carbon nanotube dispersion obtained by separating the double aqueous phase can be further separated into monochiral carbon nanotubes in a polymer system. (4) When the polymer transferred to the organic phase has a certain semiconducting property or narrow chiral separation property, the semiconducting property or monochiral purity of the carbon nanotubes in the original aqueous phase can be greatly improved.

[0039] The present application enables the transition process to be completed smoothly and efficiently through a series of transition methods including carbon nanotube aqueous phase dispersion → removal of surfactant by extraction method → ​​solvent replacement → organic phase dispersion.

[0040] In the present application, the carbon tubes in the second suspension of carbon tubes are precipitated by adding a third solvent, and this is repeated 3 to 10 times to remove 99% or more of the second solvent, essentially converting the solution into the third solvent.

[0041] The method provided in this application allows the carbon nanotube aqueous phase dispersion to be converted into an organic phase dispersion.

[0042] The technical solutions of the present application will be described in more detail below in conjunction with a number of preferred embodiments and the accompanying drawings. The present embodiments are implemented on the premise of the technical solutions of the invention, and provide detailed embodiments and specific operation steps, but the scope of protection of the present application is not limited to the following embodiments.

[0043] All experimental materials used in the following examples are commercially available from conventional biochemical reagent companies unless otherwise specified.

[0044] [Example 1] (1) HiPCO carbon tubes and sodium deoxycholate dispersant are mixed, and an aqueous phase dispersion is obtained through a dispersion process. A part of the aqueous phase dispersion is filtered to obtain a carbon tube membrane I. (2) The carbon nanotube aqueous dispersion obtained in step (1) and dimethyl sulfoxide are mixed together, and the mixture is left to stand for 15 minutes by a simple water bath ultrasonic method to obtain suspension I (wherein the volume ratio of water to dimethyl sulfoxide in suspension I is 1:3), and then chlorobenzene is added to suspension I (wherein the volume ratio of chlorobenzene to dimethyl sulfoxide is 1:2), and the mixture is thoroughly mixed and left to stand for 10 minutes, and the bottom phase is collected to obtain suspension II, and a part of suspension II is suction filtered to form carbon tube film II, and XPS tests are performed on the carbon tube films I and II, and the Na ion signal intensities are compared to determine that the surfactant is completely removed; (3) The suspension II obtained in step (2) and a 4-fold amount of toluene solution are thoroughly mixed in a separating funnel and allowed to stand, so that the carbon nanotubes are gradually suspended at the top of the solution. After removing the transparent liquid at the bottom, more toluene solution is added, and this is repeated four times to collect the suspension III; (4) The suspension III obtained in step (3) and F8T2 are mixed together, and an organic phase dispersion liquid in a HiPCO tube is obtained by an ultrasonic dispersion step.

[0045] A comparison of the XPS test results of this example is shown in FIG. 2, and a schematic flow chart of the process of transferring the DOC-dispersed HiPCO tube from the aqueous phase to the organic phase in this example is shown in FIG.

[0046] [Example 2] (1) TUBALL carbon nanotubes are mixed with Triton x-100 dispersant, and a carbon nanotube aqueous dispersion is obtained through a dispersion process. (2) The carbon nanotube aqueous dispersion obtained in step (1) and acetonitrile are mixed together, and after simple water bath ultrasonication, the mixture is left standing for 1 minute to obtain suspension I (wherein the volume ratio of water to acetonitrile in suspension I is 1:1), and then dichloromethane is added to suspension I (wherein the volume ratio of dichloromethane to acetonitrile is 0.5:1), mixed thoroughly, and left standing for 1 minute, and the bottom phase is collected to obtain suspension II; (3) The suspension II obtained in step (2) is thoroughly mixed with three times the amount of nitrobenzene solution in a separating funnel and allowed to stand, so that the carbon nanotubes are gradually suspended at the top of the solution. After removing the transparent liquid at the bottom, further nitrobenzene solution is added, and this is repeated three times to collect the suspension III; (4) The suspension III obtained in step (3) is subjected to an ultrasonic dispersion step to obtain a TUBALL carbon nanotube dispersant-free organic phase dispersion.

[0047] In this example, a schematic flow chart of the process for transferring Triton x-100 dispersed TUBALL carbon nanotubes from an aqueous phase to an organic phase is shown in FIG.

[0048] [Example 3] (1) Mixing double-walled carbon nanotubes with lauryl alcohol and oleyl alcohol dispersants, and dispersing the mixture to obtain a carbon nanotube aqueous dispersion; (2) The carbon nanotube aqueous dispersion obtained in step (1) and tetrahydrofuran are mixed together and left to stand for 15 minutes by a simple water bath ultrasonic method to obtain suspension I (wherein the volume ratio of water to tetrahydrofuran in suspension I is 1:3), and then trichloroethane is added to suspension I (wherein the volume ratio of trichloroethane to said tetrahydrofuran is 3:1), mixed thoroughly and left to stand for 10 minutes, and the bottom phase is collected to obtain suspension II; (3) The suspension II obtained in step (2) is subjected to a shearing and dispersion step to obtain a double-walled carbon nanotube dispersant-free organic phase dispersion.

[0049] [Example 4] (1) mixing metallic carbon nanotube raw material with sodium deoxycholate dispersant, and dispersing the mixture to obtain a carbon nanotube aqueous dispersion; (2) The carbon nanotube aqueous dispersion obtained in step (1) and N-methylpyrrolidone are mixed together, and after simple water bath ultrasonication, the mixture is left standing for 30 minutes to obtain suspension I (wherein the volume ratio of water to N-methylpyrrolidone in suspension I is 1:6), and then toluene is added to suspension I (wherein the volume ratio of toluene to said N-methylpyrrolidone is 6:1), mixed thoroughly, and left standing for 15 minutes, and the bottom phase is collected to obtain suspension II; (3) The suspension II obtained in step (2) and 8 times the amount of chloroform solution are thoroughly mixed in a separating funnel and allowed to stand, so that the carbon nanotubes are gradually suspended at the top of the solution. After removing the transparent liquid at the bottom, more chloroform is added, and this is repeated 10 times to collect the suspension III. (4) The suspension III obtained in the step (3) is subjected to a high pressure homogenizing dispersion step to obtain an organic dispersion of metallic single-walled carbon nanotubes.

[0050] In this example, a flow chart of the process for transferring metallic single-walled carbon nanotubes from the aqueous phase to the organic phase is shown in FIG.

[0051] [Example 5] (1) The semiconducting carbon nanotube solution obtained by the double aqueous phase separation (the absorption spectrum is shown in FIG. 6) is mixed with a saturated ammonium sulfate solution, and then centrifuged to collect a coprecipitate of carbon nanotubes and a surfactant at the bottom of the solution. (2) Redispersing the precipitate obtained in step (1) in deionized water to obtain a carbon nanotube aqueous dispersion; (3) The carbon nanotube aqueous dispersion obtained in step (2) and butanone are mixed together, and after simple water bath ultrasonication, the mixture is left standing for 15 minutes to obtain suspension I (wherein the volume ratio of water to butanone in suspension I is 1:3), and then xylene is added to suspension I (wherein the volume ratio of xylene to butanone is 3:1), mixed thoroughly, and left standing for 10 minutes, and the bottom phase is collected to obtain suspension II; (4) The suspension II obtained in step (3) and 4HP (organic dispersant) are mixed together and subjected to a sanding dispersion process to obtain a carbon nanotube organic phase dispersion liquid.

[0052] In this embodiment, a schematic flow chart of the transfer of the semiconducting carbon nanotube dispersion from the aqueous phase to the organic phase to achieve chiral separation is shown in Figure 6. The semiconducting carbon nanotube dispersion was transferred from the aqueous phase to the organic phase, and the semiconductor purity was improved from the original 76.32% to 99.9%.

[0053] [Example 6] (1) The thin carbon nanotube solution obtained by double aqueous phase separation (the absorption spectrum is shown in FIG. 7) is mixed with a saturated sodium sulfate solution and then centrifuged to collect a coprecipitate of carbon nanotubes and surfactant at the bottom of the solution. (2) Redispersing the precipitate obtained in step (1) in deionized water to obtain a carbon nanotube aqueous dispersion; (3) The carbon nanotube aqueous dispersion obtained in step (2) and N,N-dimethylformamide (DMF) are mixed together, and after simple water bath ultrasonication, the mixture is left to stand for 15 minutes to obtain suspension I (wherein the volume ratio of water to DMF in suspension I is 1:3), and then m-chlorotoluene is added to suspension I (wherein the volume ratio of m-chlorotoluene to said DMF is 3:1), mixed thoroughly, and left to stand for 10 minutes, and the bottom phase is collected to obtain suspension II; (4) thoroughly mix the suspension II obtained in step (3) with 4 times the amount of toluene solution, leave the mixture to stand, remove the upper transparent liquid, add more toluene solution, and repeat this process 4 times to collect suspension III; (5) The suspension III obtained in step (4) and F8BT are mixed together, and the mixture is subjected to an ultrasonic dispersion process to obtain (9,5) SWCNTs with a purity of 88%, and the precipitate is collected.

[0054] In this embodiment, a schematic flow chart of how chiral separation is achieved by transferring a chiral carbon nanotube dispersion from an aqueous phase to an organic phase is shown in FIG.

[0055] [Example 7] (1) The thin carbon nanotube solution obtained by double aqueous phase separation (the absorption spectrum is shown in FIG. 8) is mixed with a saturated sodium chloride solution and then centrifuged to collect a coprecipitate of carbon nanotubes and surfactant at the bottom of the solution. (2) Redispersing the precipitate obtained in step (1) in deionized water to obtain a carbon nanotube aqueous dispersion; (3) The carbon nanotube aqueous dispersion obtained in step (2) and the N,N-dimethylformamide (DMF) solution are mixed together, and after simple water bath ultrasonication, the suspension I is left standing for 15 minutes (wherein the volume ratio of water to N,N-dimethylformamide in the suspension I is 1:3). Then, m-chlorotoluene is added to the suspension I (wherein the volume ratio of m-chlorotoluene to the N,N-dimethylformamide is 3:1), mixed thoroughly, and left standing for 10 minutes. The bottom phase is collected to obtain suspension II; (4) The suspension II obtained in step (3) is thoroughly mixed with 4 times the amount of xylene solution, and allowed to stand. The transparent liquid at the top is removed, and further xylene solution is added. This is repeated 4 times to collect a carbon nanotube xylene dispersion liquid. (5) The carbon nanotube xylene dispersion obtained in step (4) and PFO-BPy are mixed together, and the mixture is subjected to an ultrasonic dispersion process to obtain (11,3) SWCNTs with a purity of 91%, and the precipitate is collected.

[0056] In this embodiment, a schematic flow chart of the chiral carbon nanotube dispersion transferred from the aqueous phase to the organic phase to achieve chiral separation is shown in FIG.

[0057] [Comparative Example 1] The carbon tube aqueous dispersion was filtered to remove the solvent, and the filtrate was directly added to a solution of toluene and dispersant and ultrasonically dispersed. The redispersed carbon tube solution in the organic phase was very unstable, with many aggregates and precipitates, and more than 80% of the carbon nanotubes had disappeared in the dispersion after being left to stand or centrifuged.

[0058] [Comparative Example 2] The aqueous phase dispersion in the HiPCO tube was added directly to chlorobenzene and mixed, but the two phases did not mix completely and phase inversion of the solvent system could not be achieved.

[0059] [Comparative Example 3] (1) The aqueous phase dispersion in the HiPCO tube is added to N,N-dimethylformamide and ultrasonically dispersed to obtain suspension I. (2) The suspension I obtained in step (1) and chloroform are mixed together, uniformly mixed and allowed to stand, forming two phases, and the bottom phase is collected as suspension II. During the phase separation process, an emulsification phenomenon occurs, and it takes time to break the emulsion.

[0060] Furthermore, the inventors of the present application have also conducted tests on other raw materials, process operations, and process conditions described in the present specification with reference to the above examples, and have obtained relatively ideal results.

[0061] It should be understood that the technical solutions of the present application are not limited to the above specific embodiments, and all technical modifications made in accordance with the technical solutions of the present application without departing from the spirit and scope of the claims of the present application are included in the protection scope of the present application.

[0062] (Additional Note) (Appendix 1) Providing an aqueous dispersion of carbon nanotubes; A step of mixing the carbon nanotube aqueous phase dispersion liquid and a first solvent containing a hydrophilic organic solvent to obtain a first suspension; mixing the first suspension with a second solvent containing a hydrophobic organic solvent to form two layered phases to obtain a second suspension; mixing the second suspension and a third solvent together to obtain a third suspension; A method for transferring a carbon nanotube aqueous phase dispersion into an organic phase dispersion, comprising the steps of: dispersing the second suspension or the third suspension to obtain a carbon nanotube organic dispersion; and achieving solvent transfer from the aqueous phase of the carbon nanotube dispersion to the organic phase.

[0063] (Appendix 2) The method described in Appendix 1, characterized in that the carbon nanotubes contained in the carbon nanotube aqueous dispersion include one or a combination of two or more of single-walled carbon nanotubes, multi-walled carbon nanotubes, and carbon nanotubes obtained by separation.

[0064] (Appendix 3) The dispersant contained in the carbon nanotube aqueous phase dispersion includes an ionic surfactant and / or a non-ionic dispersant. Preferably, the ionic surfactant includes any one or a combination of two or more of sodium deoxycholate, sodium cholate, sodium dodecyl sulfate, and sodium dodecylbenzenesulfonate. Preferably, the non-ionic dispersant includes any one or a combination of two or more of Triton, lauryl alcohol and oleyl alcohol, Tween, cyclohexanol, nonylphenol, and single-stranded DNA. And / or the method described in Appendix 1, characterized in that the carbon nanotube aqueous dispersion further contains a water-soluble additive introduced by a carbon nanotube separation process.

[0065] (Appendix 4) The method according to claim 1, characterized in that the carbon nanotube aqueous phase dispersion liquid and the first solvent are thoroughly mixed and allowed to stand for 1 to 30 minutes, whereby at least the surfactant adsorption layer on the carbon nanotube surface is destroyed under the action of the first solvent, and the carbon nanotubes are precipitated and suspended in the mixed solution.

[0066] (Appendix 5) The method according to claim 1, wherein the first solvent is an organic solvent that is miscible or partially miscible with water, and includes any one, two, or a combination of two or more of N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, N-methylpyrrolidone, dioxane, acetone, methyl ethyl ketone, butanone, ethanol, and acetonitrile.

[0067] (Appendix 6) The method according to claim 1, characterized in that the first suspension contains the carbon nanotube aqueous phase dispersion and a first solvent, and preferably, the volume ratio of water to first solvent in the first suspension is 1:1 to 1:6.

[0068] (Appendix 7) The method according to claim 1, further comprising a step of thoroughly mixing the first suspension and the second solvent and allowing the mixture to stand for 1 to 15 minutes to form two phases, wherein the carbon nanotubes are suspended in the second solvent to form the second suspension.

[0069] (Appendix 8) The second solvent includes any one or a combination of two or more of m-chlorotoluene, toluene, xylene, chlorobenzene, dichloromethane, trichloromethane, and trichloroethane; And / or, the volume ratio of the first solvent to the second solvent is 1:0.5 to 1:6.

[0070] (Appendix 9) The method according to claim 1, further comprising the steps of: adding a third solvent to the second suspension, mixing them together, allowing to stand, removing the upper transparent liquid, adding the third solvent, mixing, allowing to stand, and repeating the above steps 3 to 10 times to obtain the third suspension, preferably in a volume ratio of the second suspension to the third solvent of 1:3 to 1:8.

[0071] (Appendix 10) The third solvent is an organic solvent, and preferably, the organic solvent comprises any one or a combination of two or more of xylene, toluene, tetrahydrofuran, chlorobenzene, chloroform, and nitrobenzene; And / or the method described in Appendix 1, characterized in that the third suspension contains carbon nanotubes and a third solvent, and the content of the second solvent in the third suspension is less than 1 (v / v)%.

[0072] (Appendix 11) The method described in Appendix 1, characterized in that it includes a step of obtaining an organic dispersion of carbon nanotubes by dispersing and processing the second suspension or the third suspension under dispersant-free conditions, or a step of mixing the second suspension or the third suspension with a dispersant and dispersing to obtain an organic dispersion of carbon nanotubes, wherein the dispersant includes an organic dispersant and / or a polymer dispersant.

[0073] (Appendix 12) The method according to claim 1, characterized in that the dispersion treatment includes any one of a shear method, an ultrasonic method, a high-pressure homogenizing method, a sanding method, and a high-pressure jet method.

[0074] (Appendix 13) The method described in Appendix 1, characterized in that when obtaining the carbon nanotube aqueous phase dispersion by dual aqueous phase technique separation, the carbon nanotube aqueous phase dispersion is first pretreated to remove the water-soluble polymer in the carbon nanotube aqueous phase dispersion, and preferably the water-soluble polymer comprises polyethylene glycol and / or dextran.

[0075] (Appendix 14) The method described in Appendix 13, characterized in that the pretreatment includes mixing a saturated salt solution with a carbon nanotube dispersion and centrifuging the mixture to obtain a coprecipitate of carbon nanotubes and a surfactant, and then redispersing the coprecipitate of carbon nanotubes and a surfactant in water to obtain an aqueous dispersion of carbon nanotubes that does not contain a water-soluble polymer.

[0076] (Appendix 15) 15. The method of claim 14, wherein the salt in the saturated salt solution includes any one or a combination of two or more of ammonium sulfate, sodium sulfate, magnesium sulfate, sodium chloride, and magnesium chloride.

Claims

1. Providing an aqueous dispersion of carbon nanotubes; A step of mixing the carbon nanotube aqueous phase dispersion liquid and a first solvent containing a hydrophilic organic solvent to obtain a first suspension; mixing the first suspension with a second solvent containing a hydrophobic organic solvent to form two layered phases to obtain a second suspension; mixing the second suspension and a third solvent together to obtain a third suspension; A method for transferring a carbon nanotube aqueous phase dispersion into an organic phase dispersion, comprising the steps of: dispersing the second suspension or the third suspension to obtain a carbon nanotube organic dispersion; and achieving solvent transfer from the aqueous phase of the carbon nanotube dispersion to the organic phase.

2. The method according to claim 1, characterized in that the carbon nanotubes contained in the carbon nanotube aqueous dispersion include one or a combination of two or more of single-walled carbon nanotubes, multi-walled carbon nanotubes, and separated carbon nanotubes.

3. The dispersant contained in the carbon nanotube aqueous phase dispersion includes an ionic surfactant and / or a non-ionic dispersant. Preferably, the ionic surfactant includes any one or a combination of two or more of sodium deoxycholate, sodium cholate, sodium dodecyl sulfate, and sodium dodecylbenzenesulfonate. Preferably, the non-ionic dispersant includes any one or a combination of two or more of Triton, lauryl alcohol and oleyl alcohol, Tween, cyclohexanol, nonylphenol, and single-stranded DNA. The method according to claim 1, characterized in that the carbon nanotube aqueous dispersion further comprises a water-soluble additive introduced during a carbon nanotube separation process.

4. The method according to claim 1, characterized in that the carbon nanotube aqueous dispersion and the first solvent are thoroughly mixed and allowed to stand for 1 to 30 minutes, so that at least the surfactant adsorption layer on the carbon nanotube surface is destroyed under the action of the first solvent, and the carbon nanotubes are precipitated and suspended in the mixed solution.

5. 2. The method of claim 1, wherein the first solvent is an organic solvent that is miscible or partially miscible with water, and includes any one, two, or a combination of two or more of N,N-dimethylformamide, tetrahydrofuran, dimethylsulfoxide, N-methylpyrrolidone, dioxane, acetone, methyl ethyl ketone, butanone, ethanol, and acetonitrile.

6. The method according to claim 1, characterized in that the first suspension comprises the carbon nanotube aqueous phase dispersion and a first solvent, and preferably the volume ratio of water to the first solvent in the first suspension is 1:1 to 1:

6.

7. 2. The method of claim 1, further comprising the step of thoroughly mixing the first suspension and a second solvent and allowing the mixture to stand for 1-15 minutes to form two phases, wherein the carbon nanotubes are suspended in the second solvent to form the second suspension.

8. The second solvent includes any one or a combination of two or more of m-chlorotoluene, toluene, xylene, chlorobenzene, dichloromethane, trichloromethane, and trichloroethane; and / or the volume ratio of the first solvent to the second solvent is 1:0.5 to 1:

6.

9. 2. The method according to claim 1, comprising the steps of: adding a third solvent to the second suspension, mixing with each other, standing to remove the upper transparent liquid, adding a third solvent, mixing and standing to remove the upper transparent liquid, and repeating the above operations 3-10 times to obtain the third suspension, preferably, the volume ratio of the second suspension to the third solvent is 1:3-1:

8.

10. The third solvent is an organic solvent, and preferably, the organic solvent comprises any one or a combination of two or more of xylene, toluene, tetrahydrofuran, chlorobenzene, chloroform, and nitrobenzene; And / or the method according to claim 1, characterized in that the third suspension contains carbon nanotubes and a third solvent, and the content of the second solvent in the third suspension is less than 1 (v / v)%.

11. The method according to claim 1, characterized in that it includes a step of obtaining an organic dispersion of carbon nanotubes by dispersing and processing the second suspension or the third suspension under dispersant-free conditions, or a step of mixing the second suspension or the third suspension with a dispersant and dispersing to obtain an organic dispersion of carbon nanotubes, wherein the dispersant includes an organic dispersant and / or a polymer dispersant.

12. 2. The method of claim 1, wherein the dispersion treatment comprises one of a shearing method, an ultrasonic method, a high-pressure homogenizing method, a sanding method, and a high-pressure jet method.

13. The method according to claim 1, characterized in that when obtaining the carbon nanotube aqueous phase dispersion by dual aqueous phase technique separation, the carbon nanotube aqueous phase dispersion is first pretreated to remove the water-soluble polymer in the carbon nanotube aqueous phase dispersion, and preferably the water-soluble polymer comprises polyethylene glycol and / or dextran.

14. The method according to claim 13, characterized in that the pretreatment includes mixing a saturated salt solution with a carbon nanotube dispersion and centrifuging the mixture to obtain a co-precipitate of carbon nanotubes and a surfactant, and then redispersing the co-precipitate of carbon nanotubes and a surfactant in water to obtain an aqueous dispersion of carbon nanotubes that does not contain a water-soluble polymer.

15. 15. The method of claim 14, wherein the salt in the saturated salt solution comprises any one or a combination of two or more of ammonium sulfate, sodium sulfate, magnesium sulfate, sodium chloride, magnesium chloride.

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