A method for transferring carbon nanotube aqueous dispersion to organic dispersion

Abstract

The present invention discloses a method for transposing a carbon nanotube aqueous phase dispersion into an organic phase dispersion. The method comprises: providing a carbon nanotube aqueous phase dispersion; mixing the carbon nanotube aqueous phase dispersion with a first solvent to obtain a first suspension; wherein the first solvent comprises a hydrophilic organic solvent; mixing the first suspension with a second solvent to form two stratified phases to obtain a second suspension; wherein the second solvent comprises a hydrophobic organic solvent; mixing the second suspension with a third solvent to obtain a third suspension; and dispersing the second suspension or the third suspension to obtain a carbon nanotube organic dispersion, thereby realizing solvent transposition of the carbon nanotubes and realizing solvent transposition of the carbon nanotube dispersion from the aqueous phase to the organic phase. The method provided by the present invention can transpose the carbon nanotube aqueous phase dispersion into the organic phase dispersion, and the transposition efficiency is 70%-95%.

Description

Technical Field

[0001] The invention belongs to the technical field of separation and purification, and in particular relates to a method for transferring a carbon nanotube aqueous phase dispersion liquid to an organic phase dispersion liquid. Background Art

[0002] Since carbon nanotubes have excellent optical and electrical properties, they are considered to be the most promising materials in nanoscience and technology. In recent years, the dispersion and separation technology of carbon nanotubes has developed rapidly, such as surfactant-coated aqueous systems, density gradient ultracentrifugation, ion exchange chromatography, gel chromatography column method, electrophoresis, two-phase aqueous separation system, etc. These methods can disperse or separate multi-walled carbon nanotubes or single-walled carbon nanotubes to a certain extent. At the same time, carbon nanotubes for different practical applications need to be dispersed in different solvents or dispersant systems. For example, the application of single-walled carbon nanotubes in the electronic field requires less polymer or dispersant, so that the Schottky barrier between the tubes and the resistance between the carbon tubes and the electrodes are reduced to enhance the application performance of single-walled carbon nanotubes in the electronic field. For example, narrow diameter chiral carbon tubes or semiconductors and metal tubes can be easily separated in the aqueous phase, but there are more surfactants on the surface of the carbon tubes and it is difficult to further separate them, which limits the application of carbon tube optoelectronics. For example, single-walled carbon nanotubes with higher purity or specific chirality dispersed in the organic phase can better meet the application of carbon nanotube optoelectronics. For example, multi-walled tubes have good electrical conductivity. A large amount of surfactant needs to be added to disperse multi-walled tubes in the water phase, which reduces the electrical conductivity of multi-walled tubes. For example, multi-walled tubes dispersed in the organic phase have good electrical conductivity. Therefore, if the current aqueous phase dispersant system can be replaced with an organic phase solution, it is expected to better broaden the application prospects of carbon nanotubes.

[0003] In order to achieve the replacement between carbon nanotube solution systems, the first goal is to remove the dispersant in the current solution as much as possible. For example, in the aqueous system, since the dispersant on the surface of the carbon tube is in a dynamic equilibrium with the solution, some researchers have tried to remove the surfactant by filtration and dialysis, but these methods will lead to the aggregation of carbon tubes, and the surface cleanliness of the collected carbon tubes is low. The second goal is to redisperse the carbon nanotubes in the solution in a new solvent under suitable dispersion conditions to meet its application in various fields. The current shortcomings are: first, the surfactant outside the carbon tube cannot be effectively removed; second, there are many agglomerations between carbon tubes.

[0004] There are very few technologies that can cover all of these aspects at the same time. Many studies have been conducted on the removal of surfactants from aqueous solutions, but there are few studies on the problem of carbon tube agglomeration. Jamie E. Rossi et al. collected single-walled carbon nanotubes through a filtration process. The surfactants can be effectively removed by combining organic solvent washing and high-temperature treatment. However, this will cause strong interaction forces between carbon tubes, making it difficult to achieve system transposition. Han Li and his collaborators enriched carbon tubes through filtration, and the process of water phase transposition to organic phase can be achieved through multiple ethanol washings. This cleaning process will aggravate the agglomeration of carbon tubes, and the transposition process will cause large losses and take a long time. Robert Niβler and his collaborators used a salt layer filtration method, which can not only effectively remove carbon tube surfactants, but also ensure that carbon tubes are reduced in agglomeration, and more effectively transfer carbon tubes from the organic phase to the aqueous phase. However, the salt layer filtration method is no longer applicable when transferring from the aqueous phase to the organic phase. However, the above method still has many disadvantages. On the one hand, the time consumption of the filtration process will be sharply extended with the increase in the number of carbon tubes, making it difficult to achieve large-scale application; on the other hand, the filtration and cleaning process will bring about the agglomeration problem of carbon tubes, and redispersion will lead to a high proportion of carbon tube loss and require a lot of time and energy. Summary of the invention

[0005] The main purpose of the present invention is to provide a method for transferring a carbon nanotube aqueous phase dispersion into an organic phase dispersion to overcome the shortcomings of the prior art.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0007] The embodiment of the present invention provides a method for transferring a carbon nanotube aqueous phase dispersion into an organic phase dispersion, which comprises:

[0008] Providing a carbon nanotube aqueous dispersion;

[0009] Mixing the carbon nanotube aqueous dispersion with a first solvent to obtain a first suspension; wherein the first solvent comprises a hydrophilic organic solvent;

[0010] The first suspension and the second solvent are mixed to form two phases, thereby obtaining a second suspension; wherein the second solvent comprises a hydrophobic organic solvent;

[0011] mixing the second suspension and a third solvent to obtain a third suspension;

[0012] Furthermore, the second suspension or the third suspension is subjected to a dispersion treatment to obtain a carbon nanotube organic dispersion, thereby achieving solvent transposition of the carbon nanotube dispersion from an aqueous phase to an organic phase.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] (1) The present invention can ensure high cleanliness of carbon nanotubes through the extraction process and solvent conversion process, and at the same time transfer the carbon nanotube dispersion from the aqueous phase to the organic phase with a transfer efficiency of 70%-95%;

[0015] (2) If the polymer transferred in the organic phase has certain semiconductor or narrow chiral separation properties, the semiconductor or single chiral purity of the carbon nanotubes in the original aqueous phase will be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 is a schematic flow diagram of a method for transferring a carbon nanotube aqueous phase dispersion into an organic phase dispersion in a typical embodiment of the present invention;

[0018] Figure 2 is a comparison chart of the XPS test results in Example 1;

[0019] Figure 3 It is a schematic diagram of the process of transferring the DOC-dispersed HiPCO tube from the aqueous phase to the organic phase in Example 1 of the present invention;

[0020] Figure 4 It is a schematic diagram 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 invention;

[0021] Figure 5 Schematic diagram of the process of transferring the double-walled carbon nanotubes dispersed in lauryl alcohol and oleyl alcohol from the aqueous phase to the organic phase in Example 3 of the present invention

[0022] Figure 6 is a schematic diagram of the process of transferring the metallic carbon nanotube dispersion from the aqueous phase to the organic phase in Example 4 of the present invention;

[0023] Figure 7 is a schematic diagram of a process for transferring a semiconductor carbon nanotube dispersion from an aqueous phase to an organic phase to improve semiconductor purity in Example 5 of the present invention;

[0024] Figure 8 is a schematic diagram 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 invention;

[0025] Fig. 9 It is a schematic diagram of the process of transferring the chiral carbon nanotube dispersion from the aqueous phase to the organic phase to achieve chiral separation in Example 7 of the present invention. DETAILED DESCRIPTION

[0026] In view of the defects of the prior art, the inventors of this case have proposed the technical solution of the present invention after long-term research and extensive practice. It mainly realizes the smooth and efficient completion of the transposition process through a series of transposition methods of carbon nanotube aqueous phase dispersion → extraction method to remove surfactant → solvent replacement → organic phase dispersion.

[0027] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Specifically, as one aspect of the technical solution of the present invention, a method for transferring a carbon nanotube aqueous dispersion into an organic dispersion comprises:

[0029] Providing a carbon nanotube aqueous dispersion;

[0030] Mixing the carbon nanotube aqueous dispersion with a first solvent to obtain a first suspension; wherein the first solvent comprises a hydrophilic organic solvent;

[0031] The first suspension and the second solvent are mixed to form two phases, thereby obtaining a second suspension; wherein the second solvent comprises a hydrophobic organic solvent;

[0032] mixing the second suspension and a third solvent to obtain a third suspension;

[0033] Furthermore, the second suspension or the third suspension is subjected to a dispersion treatment to obtain a carbon nanotube organic dispersion, thereby achieving solvent transposition of the carbon nanotube dispersion from an aqueous phase to an organic phase.

[0034] In some preferred embodiments, the carbon nanotubes contained in the carbon nanotube aqueous dispersion include any one of single-walled carbon nanotubes, multi-walled carbon nanotubes, and separated carbon nanotubes, or a combination of two or more thereof, but are not limited thereto.

[0035] In some preferred embodiments, the dispersant contained in the carbon nanotube aqueous dispersion includes an ionic surfactant and / or a non-ionic dispersant, but is not limited thereto.

[0036] Furthermore, the ionic surfactant includes any one or a combination of two or more of sodium deoxycholate, sodium cholate, sodium dodecyl sulfate, and sodium dodecylbenzenesulfonate, but is not limited thereto.

[0037] Furthermore, the nonionic dispersant includes any one or a combination of two or more of Triton, lauryl alcohol, oleyl alcohol, Tween, cyclohexanol, nonylphenol, and single-stranded DNA, but is not limited thereto.

[0038] Furthermore, the carbon nanotube aqueous dispersion also includes water-soluble additives introduced during the carbon nanotube separation process. The water-soluble additives include dextran, polyethylene glycol, polyacrylamide, polyethylene glycol diamine, and polyvinyl pyrrolidone introduced during the two-phase separation process; iodixanol or cesium chloride introduced during the gradient density centrifugation process; and buffer solutions (such as sodium chloride solution, sodium hypochlorite solution, sodium thiocyanate solution, etc.) introduced during the DNA separation process.

[0039] In some preferred embodiments, the method specifically includes: fully mixing the carbon nanotube aqueous dispersion with a first solvent and standing for 1 to 30 minutes, so that at least the active agent adsorption layer on the surface of the carbon nanotubes is destroyed by the first solvent, thereby allowing the carbon nanotubes to precipitate and suspend in the mixed solution.

[0040] In some preferred embodiments, the first solvent is an organic solvent that is miscible or partially miscible with water, including any one of N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, N-methylpyrrolidone, dioxane, acetone, methyl ethyl ketone, butanone, ethanol, and acetonitrile, or a combination of two or more thereof, and is not limited thereto.

[0041] In some preferred embodiments, the first suspension includes the carbon nanotube aqueous dispersion and a first solvent.

[0042] Furthermore, the volume ratio of water to the first solvent in the first suspension is 1:1 to 1:6.

[0043] In some preferred embodiments, the method specifically comprises: fully mixing the first suspension and the second solvent and standing for 1 to 15 minutes to form two phases, wherein the carbon nanotubes are suspended in the second solvent to form the second suspension.

[0044] In some preferred embodiments, the second solvent includes any one or a combination of two or more of m-chlorotoluene, toluene, xylene, chlorobenzene, dichloromethane, chloroform, and trichloroethane, and is not limited thereto.

[0045] In some preferred embodiments, the volume ratio of the first solvent to the second solvent is 1:0.5 to 1:6.

[0046] In some preferred embodiments, the method specifically comprises: adding a third solvent to the second suspension, mixing them together and letting them stand, removing the supernatant, then adding a third solvent again, mixing them together and letting them stand, repeating the above operation 3-10 times to obtain the third suspension.

[0047] Furthermore, the volume ratio of the second suspension to the third solvent is 1:3 to 1:8.

[0048] 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)%.

[0049] In some preferred embodiments, the method specifically includes: dispersing the second suspension or the third suspension in the absence of a dispersant to obtain a carbon nanotube organic dispersion; or, mixing the second suspension or the third suspension with a dispersant to obtain a carbon nanotube organic dispersion through a dispersion process; wherein the dispersant includes an organic dispersant and / or a polymer dispersant.

[0050] In some preferred embodiments, the dispersion treatment method includes any one of shearing, ultrasound, homogenization, sand milling, ball milling, high-pressure jet and the like, but is not limited thereto.

[0051] In some preferred embodiments, when the carbon nanotube aqueous dispersion is obtained by separation using a two-phase aqueous technology, the carbon nanotube aqueous dispersion is first pretreated to remove water-soluble polymers in the carbon nanotube aqueous dispersion.

[0052] Specifically, if the carbon nanotube aqueous dispersion is obtained by separation using a two-phase aqueous technology, it will contain a large amount of water-soluble polymers, including polyethylene glycol, dextran, etc., and pretreatment is required before the system transfer step to remove these water-soluble polymers.

[0053] Further, the water-soluble polymer includes polyethylene glycol and / or dextran, but is not limited thereto.

[0054] Furthermore, the pretreatment includes: mixing a saturated salt solution with a carbon nanotube dispersion and centrifuging 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 a carbon nanotube aqueous phase dispersion free of water-soluble polymers.

[0055] Furthermore, 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, but is not limited thereto.

[0056] In some more specific embodiments, the method of transferring the carbon nanotube aqueous dispersion to an organic dispersion (schematic flow chart as shown in FIG. Figure 1 shown) include:

[0057] Step 1: The carbon nanotube aqueous dispersion and the first solvent are mixed and allowed to stand for 1 to 30 minutes. Under the action of the first solvent, the carbon nanotube surfactant adsorption layer is destroyed, and the carbon nanotubes are precipitated and suspended in the solution within 2 to 20 minutes to obtain a suspension I (i.e., the aforementioned "first suspension", the solvents are water and the first solvent, and the suspension is carbon nanotubes);

[0058] Step 2: Add the second solvent to the suspension I, mix them and let them stand. The solution will form two phases within 1 to 15 minutes. The surfactant will be extracted into the aqueous phase due to its hydrophilicity, and the carbon nanotubes will be suspended in the organic phase solution due to its hydrophobicity, thereby obtaining a suspension II (i.e., the aforementioned "second suspension", the solvent is the second solvent, and the suspended matter is the carbon nanotubes);

[0059] Step 3: Add the third solvent to the suspension II, mix them together and let them stand. The carbon nanotubes will gradually settle to the bottom of the solution. At this time, the carbon nanotubes are in a loose and non-violent agglomeration state. Remove the upper clear liquid, add the third solvent again, mix them together and let them stand. Repeat this step 3-10 times to obtain the suspension III (i.e., the aforementioned "third suspension", the solvent is the third solvent, and the suspended matter is the carbon nanotubes).

[0060] Step 4: The suspension II or the suspension III is subjected to a dispersion process to obtain a carbon nanotube organic dispersion;

[0061] The purpose of the present invention is to remove carbon nanotube surfactants while reducing the agglomeration of carbon nanotubes, so that the system transposition process becomes convenient and efficient. The present invention provides a method for realizing the transposition of an aqueous phase system into an organic system by utilizing the hydrophobicity of carbon nanotubes and the hydrophilicity of surfactants through extraction and separation. First, a carbon nanotube aqueous phase dispersion is mixed with a first solvent (such as N,N-dimethylformamide) to dissolve the surfactant in the first solvent, and the carbon nanotubes are suspended in the solution. Finally, a second solvent (such as m-chlorotoluene) is added. After mixing and standing, a second solvent suspension of pure carbon nanotubes can be collected in the bottom phase; finally, the second solvent carbon nanotube suspension is mixed with a third solvent (such as xylene), and the upper layer solution is removed after standing. After 3 to 10 cycles, a third solvent carbon nanotube suspension can be collected. The advantages of this scheme are: (1) After the extraction process and the solvent conversion process, the high cleanliness of the carbon nanotubes is guaranteed, and at the same time, the transposition efficiency is 70%-95% to transfer the carbon nanotube dispersion from the aqueous phase to the organic phase. (2) The carbon nanotubes in the second solvent dispersion of carbon nanotubes can be precipitated by adding a third solvent, and more than 99% of the second solvent can be removed by 3 to 10 cycles, basically converting the solvent into the third solvent. (3) By combining the salting-out process with the extraction process, the narrow diameter carbon nanotube dispersion obtained by the two-phase separation can be further separated into single-chirality carbon nanotubes in the polymer system. (4) If the polymer transferred in the organic phase has certain semiconductor or narrow chirality separation properties, the semiconductor or single-chirality purity of the carbon nanotubes in the original aqueous phase will be significantly improved.

[0062] The present invention realizes a series of transposition methods of carbon nanotube aqueous phase dispersion → extraction method to remove surfactant → solvent replacement → organic phase dispersion, so as to realize smooth and efficient completion of the transposition process.

[0063] The present invention can add the third solvent to make the carbon tubes in the second carbon tube suspension settle, and remove more than 99% of the second solvent through 3 to 10 cycles to basically convert the solution into the third solvent.

[0064] The method provided by the invention can realize the transfer of carbon nanotube aqueous phase dispersion liquid into organic phase dispersion liquid.

[0065] The technical solution of the present invention is further described in detail below in conjunction with several preferred embodiments and drawings. This embodiment is implemented on the premise of the technical solution of the invention, and a detailed implementation method and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0066] Unless otherwise specified, the experimental materials used in the following examples can be purchased from conventional biochemical reagent companies.

[0067] Example 1

[0068] (1) HiPCO carbon tubes and sodium deoxycholate dispersant are mixed and dispersed to obtain an aqueous dispersion; a portion of the aqueous dispersion is filtered to obtain a carbon tube film I;

[0069] (2) The carbon nanotube aqueous dispersion obtained in step (1) is mixed with dimethyl sulfoxide, subjected to simple water bath sonication, and allowed to stand for 15 minutes to obtain a suspension I (wherein the volume ratio of water to dimethyl sulfoxide in the suspension I is 1:3); then chlorobenzene is added to the suspension I (wherein the volume ratio of chlorobenzene to the aforementioned dimethyl sulfoxide is 1:2), the mixture is fully mixed and allowed to stand for 10 minutes, and the lower phase is collected to obtain a suspension II; a portion of the suspension II is filtered to obtain a carbon nanotube film II, and the two batches of carbon nanotube films I and II are subjected to XPS testing. By comparing the Na ion signal intensity therein, it can be determined that the surfactant is completely removed;

[0070] (3) The suspension II obtained in step (2) is fully mixed with 4 times the amount of toluene solution in a separatory funnel, and the carbon nanotubes are gradually suspended to the top of the solution after standing. After removing the clear liquid at the bottom, further toluene solution is added; after 4 cycles, a suspension III can be collected;

[0071] (4) The suspension III obtained in step (3) is mixed with F8T2, and a HiPCO tube organic phase dispersion is obtained by ultrasonic dispersion.

[0072] The XPS test results of this embodiment are compared with Figure 2 As shown;

[0073] The schematic diagram of the process of transferring the DOC dispersed HiPCO tube from the aqueous phase to the organic phase in this embodiment is shown in FIG. Figure 3 shown.

[0074] Example 2

[0075] (1) mixing TUBALL carbon nanotubes with Triton X-100 dispersant and performing a dispersion process to obtain a carbon nanotube aqueous dispersion;

[0076] (2) The carbon nanotube aqueous dispersion obtained in step (1) was mixed with acetonitrile, subjected to simple water bath sonication, and allowed to stand for 1 min to obtain a suspension I (wherein the volume ratio of water to acetonitrile in the suspension I was 1:1); then dichloromethane was added to the suspension I (wherein the volume ratio of dichloromethane to the aforementioned acetonitrile was 0.5:1), mixed thoroughly, and allowed to stand for 1 min, and the lower phase was collected to obtain a suspension II;

[0077] (3) The suspension II obtained in step (2) is fully mixed with 3 times the amount of nitrobenzene solution in a separatory funnel, and the carbon nanotubes are gradually suspended to the top of the solution after standing. After removing the clear liquid at the bottom, further nitrobenzene solution is added; after 3 cycles, a suspension III can be collected;

[0078] (4) The suspension III obtained in step (3) is subjected to an ultrasonic dispersion process to obtain a TUBALL carbon nanotube dispersant-free organic phase dispersion.

[0079] In this embodiment, the schematic diagram of the process of transferring TUBALL carbon nanotubes dispersed in Triton X-100 from the aqueous phase to the organic phase is shown in FIG4 .

[0080] Example 3

[0081] (1) mixing double-walled carbon nanotubes with a lauryl alcohol and oleyl alcohol dispersant to obtain a carbon nanotube aqueous dispersion through a dispersion process;

[0082] (2) The carbon nanotube aqueous dispersion obtained in step (1) was mixed with tetrahydrofuran, subjected to simple water bath ultrasound, and allowed to stand for 15 minutes to obtain a suspension I (wherein the volume ratio of water to tetrahydrofuran in the suspension I was 1:3); trichloroethane was then added to the suspension I (wherein the volume ratio of trichloroethane to the aforementioned tetrahydrofuran was 3:1), mixed thoroughly, and allowed to stand for 10 minutes, and the lower phase was collected to obtain a suspension II;

[0083] (3) The suspension II obtained in step (2) is subjected to a shear dispersion process to obtain a double-walled carbon nanotube dispersant-free organic phase dispersion.

[0084] In this embodiment, the process diagram of transferring the double-walled carbon nanotubes dispersed in lauryl alcohol and oleyl alcohol from the aqueous phase to the organic phase is shown in FIG. Figure 5 shown.

[0085] Example 4

[0086] (1) mixing a metallic carbon nanotube raw material with a sodium deoxycholate dispersant and subjecting the mixture to a dispersion process to obtain a carbon nanotube aqueous dispersion;

[0087] (2) The carbon nanotube aqueous dispersion obtained in step (1) was mixed with N-methylpyrrolidone, subjected to simple water bath ultrasound, and allowed to stand for 30 minutes to obtain a suspension I (wherein the volume ratio of water to N-methylpyrrolidone in the suspension I was 1:6); then toluene was added to the suspension I (wherein the volume ratio of toluene to the aforementioned N-methylpyrrolidone was 6:1), mixed thoroughly, and allowed to stand for 15 minutes, and the lower phase was collected to obtain a suspension II;

[0088] (3) The suspension II obtained in step (2) is fully mixed with 8 times the amount of chloroform solution in a separatory funnel, and the carbon nanotubes are gradually suspended to the top of the solution after standing. After removing the clear liquid at the bottom, chloroform is further added; after 10 cycles, a suspension III can be collected;

[0089] (4) The suspension III obtained in step (3) is subjected to a high-pressure homogenization dispersion process to obtain a metallic single-walled carbon nanotube organic dispersion.

[0090] In this embodiment, the process of transferring the metallic single-walled carbon nanotubes from the aqueous phase to the organic phase is as follows: Figure 6 shown.

[0091] Example 5

[0092] (1) The semiconducting carbon nanotube solution (absorption spectrum as shown in FIG. Figure 7 As shown) is mixed with a saturated ammonium sulfate solution, and then centrifuged to collect the carbon nanotubes and the surfactant co-precipitate at the bottom of the solution;

[0093] (2) redispersing the precipitate obtained in step (1) in deionized water to obtain a carbon nanotube aqueous dispersion;

[0094] (3) The carbon nanotube aqueous dispersion obtained in step (2) was mixed with butanone, subjected to simple water bath ultrasound, and allowed to stand for 15 minutes to obtain a suspension I (wherein the volume ratio of water to butanone in the suspension I was 1:3); then xylene was added to the suspension I (wherein the volume ratio of xylene to the aforementioned butanone was 3:1), mixed thoroughly, and allowed to stand for 10 minutes, and the lower phase was collected to obtain a suspension II;

[0095] (4) The suspension II obtained in step (3) is mixed with 4HP (organic dispersant), and a carbon nanotube organic phase dispersion is obtained by a sand milling dispersion process.

[0096] In this embodiment, the semiconductor carbon nanotube dispersion is transferred from the aqueous phase to the organic phase to achieve chiral separation. Figure 7 As shown, the semiconductor carbon nanotube dispersion is transferred from the aqueous phase to the organic phase, and the semiconductor purity is purified from the original 76.32% to 99.9%.

[0097] Example 6

[0098] (1) The narrow diameter carbon nanotube solution obtained by two-phase separation (absorption spectrum as shown in FIG. Figure 8 As shown) is mixed with a saturated sodium sulfate solution, and then centrifuged to collect the carbon nanotubes and the surfactant co-precipitate at the bottom of the solution;

[0099] (2) redispersing the precipitate obtained in step (1) in deionized water to obtain a carbon nanotube aqueous dispersion;

[0100] (3) The carbon nanotube aqueous dispersion obtained in step (2) was mixed with N,N-dimethylformamide (DMF), subjected to simple water bath ultrasound, and allowed to stand for 15 minutes to obtain a suspension I (wherein the volume ratio of water to DMF in the suspension I was 1:3); then m-chlorotoluene was added to the suspension I (wherein the volume ratio of m-chlorotoluene to the aforementioned DMF was 3:1), mixed thoroughly, and allowed to stand for 10 minutes, and the lower phase was collected to obtain a suspension II;

[0101] (4) The suspension II obtained in step (3) is fully mixed with four times the amount of toluene solution, the supernatant is removed after standing, and the toluene solution is further added; after four cycles, the suspension III can be collected;

[0102] (5) mixing the suspension III obtained in step (4) with F8BT, obtaining (9,5) SWCNTs with a purity of 88% through an ultrasonic dispersion process, and collecting the precipitate;

[0103] In this embodiment, the chiral carbon nanotube dispersion is transferred from the aqueous phase to the organic phase to achieve chiral separation. Figure 8 shown.

[0104] Example 7

[0105] (1) The narrow diameter carbon nanotube solution obtained by two-phase separation (absorption spectrum as shown in FIG. Fig. 9 As shown) is mixed with a saturated sodium chloride solution, and then centrifuged to collect the carbon nanotubes and the surfactant co-precipitate at the bottom of the solution;

[0106] (2) redispersing the precipitate obtained in step (1) in deionized water to obtain a carbon nanotube aqueous dispersion;

[0107] (3) The carbon nanotube aqueous dispersion obtained in step (2) was mixed with the N,N-dimethylformamide (DMF) solution, subjected to simple water bath sonication, and allowed to stand for 15 minutes to obtain a suspension I (wherein the volume ratio of water to dimethyl sulfoxide in the suspension I was 1:3); then m-chlorotoluene was added to the suspension I (wherein the volume ratio of chlorobenzene to the aforementioned dimethyl sulfoxide was 3:1), the mixture was fully mixed and allowed to stand for 10 minutes, and the lower phase was collected to obtain a suspension II;

[0108] (4) The suspension II obtained in step (3) is fully mixed with four times the amount of xylene solution, after standing, the upper clear liquid is removed, and the xylene solution is further added; after four cycles, the carbon nanotube xylene dispersion can be collected;

[0109] (5) mixing the carbon nanotube xylene dispersion obtained in step (4) with PFO-BPy, obtaining (11,3) SWCNTs with a purity of 91% through an ultrasonic dispersion process, and collecting the precipitate;

[0110] In this embodiment, the chiral carbon nanotube dispersion is transferred from the aqueous phase to the organic phase to achieve chiral separation, as shown in Figure 9.

[0111] Comparative Example 1

[0112] The carbon tube aqueous dispersion is filtered to remove the solvent, and the filtrate is directly placed in a solution of toluene and dispersant for ultrasonic dispersion. The redispersed carbon tube solution in the organic phase is extremely unstable, and a large amount of flocculation and precipitation occurs; more than 80% of the carbon nanotubes are lost in the dispersion after standing or centrifugal treatment.

[0113] Comparative Example 2

[0114] The aqueous dispersion of the HiPCO tube was directly added to chlorobenzene for mixing. The two phases were completely immiscible and the solvent system transposition could not be completed.

[0115] Comparative Example 3

[0116] (1) Add the HiPCO tube aqueous dispersion into N,N-dimethylformamide for ultrasonic dispersion to obtain suspension I;

[0117] (2) The suspension I obtained in step (1) is mixed with chloroform, and after mixing and standing, two phases are formed, and the lower phase is the suspension II; emulsification will occur during the phase separation process, and demulsification takes a long time.

[0118] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0119] It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific implementation cases. Any technical deformation made according to the technical solution of the present invention without departing from the scope of protection of the purpose of the present invention and the claims shall fall within the protection scope of the present invention.

Claims

1. A method for transferring a carbon nanotube aqueous dispersion into an organic dispersion, Features include: A carbon nanotube aqueous dispersion is provided; wherein the dispersant contained in the carbon nanotube aqueous dispersion comprises an ionic surfactant and / or a non-ionic dispersant; the ionic surfactant comprises any one of sodium deoxycholate, sodium cholate, sodium dodecyl sulfate, and sodium dodecylbenzenesulfonate, or a combination of two or more thereof; the non-ionic dispersant comprises any one of Triton, lauryl alcohol, oleyl alcohol, Tween, cyclohexanol, nonylphenol, and single-stranded DNA, or a combination of two or more thereof; The carbon nanotube aqueous dispersion and a first solvent are mixed together, so that at least the active agent adsorption layer on the surface of the carbon nanotubes is destroyed under the action of the first solvent, so that the carbon nanotubes are precipitated and suspended in the mixed solution to obtain a first suspension; wherein the first solvent includes a hydrophilic organic solvent; The first suspension and the second solvent are mixed to form two phases, thereby obtaining a second suspension; wherein the second solvent comprises a hydrophobic organic solvent; and the carbon nanotubes are suspended in the second solvent to form the second suspension; The second suspension and the third solvent are mixed to obtain a third suspension; wherein the third solvent is an organic solvent; the organic solvent includes any one of xylene, toluene, chloroform, and nitrobenzene, or a combination of two or more thereof; Furthermore, the second suspension or the third suspension is subjected to a dispersion treatment to obtain a carbon nanotube organic dispersion, thereby achieving solvent transposition of the carbon nanotube dispersion from an aqueous phase to an organic phase.

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

3. The method according to claim 1, Features: The carbon nanotube aqueous phase dispersion also includes a water-soluble additive introduced during the carbon nanotube separation process.

4. The method according to claim 1, Features include: The carbon nanotube aqueous dispersion and the first solvent are fully mixed and allowed to stand for 1 to 30 minutes.

5. The method according to claim 1, Features: The first solvent is an organic solvent that is miscible or partially miscible with water, including any one of N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, N-methylpyrrolidone, dioxane, acetone, methyl ethyl ketone, butanone, ethanol, and acetonitrile, or a combination of two or more thereof.

6. The method according to claim 1, Features: The first suspension includes the carbon nanotube aqueous dispersion and a first solvent; the volume ratio of water to the first solvent in the first suspension is 1:1-1:

6.

7. The method according to claim 1, Features include: The first suspension and the second solvent are fully mixed and allowed to stand for 1 to 15 minutes to form two phases.

8. The method according to claim 1, Features: The second solvent includes any one of meta-chlorotoluene, toluene, xylene, chlorobenzene, dichloromethane, chloroform, and trichloroethane, or a combination of two or more thereof.

9. The method according to claim 1, Features: The volume ratio of the first solvent to the second solvent is 1:0.5~1:

6.

10. The method according to claim 1, Features include: Add the third solvent to the second suspension, mix them together and let them stand, remove the supernatant, then add the third solvent again, mix them together and let them stand, repeat the above operation 3-10 times to obtain the third suspension; the volume ratio of the second suspension to the third solvent is 1:3-1:

8.

11. The method according to claim 1, Features: The third suspension includes carbon nanotubes and a third solvent, wherein the content of the second solvent in the third suspension is less than 1 (v / v) %.

12. The method according to claim 1, Features include: The second suspension or the third suspension is dispersed in the absence of a dispersant to obtain a carbon nanotube organic dispersion; or the second suspension or the third suspension is mixed with a dispersant to obtain a carbon nanotube organic dispersion through a dispersion process; wherein the dispersant includes an organic dispersant and / or a polymer dispersant.

13. The method according to claim 1, Features: The dispersion treatment method includes any one of shearing, ultrasound, high-pressure homogenization, sand milling, and high-pressure jet methods.

14. The method according to claim 1, Features: When the carbon nanotube aqueous dispersion is obtained by separation using a two-phase aqueous technology, the carbon nanotube aqueous dispersion is first pretreated to remove water-soluble polymers in the carbon nanotube aqueous dispersion; The water-soluble polymer includes polyethylene glycol and / or dextran.

15. The method according to claim 14, It is characterized in that The pretreatment comprises: mixing a saturated salt solution with a carbon nanotube dispersion and centrifuging 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 a carbon nanotube aqueous phase dispersion free of water-soluble polymers.

16. The method according to claim 15, Features The salt in the saturated salt solution includes any one of ammonium sulfate, sodium sulfate, magnesium sulfate, sodium chloride, and magnesium chloride, or a combination of two or more thereof.

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